Dissertations / Theses: 'Trypanosomiasis in animals'

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Smuts, Celia Margaretha. "Development of tools to improve the detection of Trypanoma evansi in Australia /." Murdoch University Digital Theses Program, 2009. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20090709.113425.

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Tchamo, Cesaltina da Conceicao Lopes Menete. "Evaluation of the pathogenicity in goats of Trypanosoma congolense from Matutuine, Mozambique." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-04212008-143822/.

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Schaten, Kathrin Maria. "One Health approach to measure the impact on wellbeing of selected infectious diseases in humans and animals in Zambia." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33198.

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This study describes the results of a cross-sectional survey conducted in Mambwe district in the Eastern Province in Zambia. It uses a One Health approach to assess the impact of veterinary, medical, environmental and social determinants on animal and human health and wellbeing. One Health is defined as a holistic and interdisciplinary approach that describes the complexities between people, animals, the environment and their health. Human wellbeing is defined in this thesis as 'a condition in which all members of society are able to determine and meet their needs and have a large range of choices to meet their potential' (Prescott-Allen, 2001). As a first step, eight focus group discussions with the inhabitants followed by key informant interviews with stakeholders in the area were conducted to give a primary impression and narrow down the problems in relation to animal and human health of the area in general. Following this, a randomized selection of 210 households was visited and in each household blood samples were taken from all humans and all animals belonging to five animal species, namely cattle, goats, sheep, pigs and dogs. A third of the households did not keep any of the animal species chosen for sampling, but their inclusion was important for the social analysis. In all of these 210 households a wellbeing questionnaire was administered and, for every human and animal sampled, a health questionnaire. The study area falls within the tsetse-infested region of Zambia. It has a high wildlife density reflecting the proximity of several national parks and is historically endemic for both human and animal African trypanosomiasis (HAT&AAT). Therefore humans and animals were tested for trypanosomiasis using internal transcribed spacer (ITS) polymerase chain reaction (PCR). Since it is important as a differential diagnosis, malaria was tested for by a rapid diagnostic test in the field from human blood. Sera from mature individuals from all animal species except pigs were tested in a field laboratory for brucellosis using the Rose Bengal test. Additionally, cattle and dogs were tested for five genera of tick-borne infections (TBI) including Anaplasma, Ehrlichia, Theileria, Babesia and Rickettsia using reverse line blot (RLB) in the laboratory at the University of Edinburgh (UoE). The blood samples for PCR and RLB analysis at UoE were stored on WhatmanTM FTA cards. A total of 1012 human samples were tested for HAT and none found positive. 1005 (seven people had been tested positive or treated against malaria shortly before the sampling) people tested for malaria showed an overall prevalence of 15% (95% CI 13.2-17.7). None of the 734 Rose Bengal tests showed up positive for brucellosis. The prevalence of AAT in 1275 samples tested was much lower compared to former samplings; in cattle 22% (95% CI 18-27.2), in goats 7% (95% CI 4.5-9.2), in pigs 6% (95% CI 3.2-9.4), in dogs 9% (95% CI 5.2-13.6) and no samples were found positive in sheep. The prevalence of TBIs is much more complex with many multiple infections. A total of 340 cattle and 195 dogs were tested. In cattle the number of samples positive for any microorganism was as follows; 92% (95% CI 88- 94.2). Overall there were fewer positive samples from dogs with 25% of animals infected (95% CI 19.2-31.8). The wellbeing and health questionnaires were designed to help to identify possible risk factors for the above-mentioned diseases and signs, such as fever, diarrhoea and seizures, indicative for several other diseases. The results of these surveys might also help to identify potential reasons for a lower or higher prevalence of trypanosomiasis and malaria found than expected from previous studies. Additionally, information on personal happiness, attitudes towards veterinary and medical services, medical treatments received, education, women's reproductive history, drug abuse, people's perceptions of changes in environment and agriculture, demography, poverty and migration were collected via the questionnaires alongside information on livestock demographics and fertility. One of the main conclusions is that both medical and veterinary health care systems suffer from a number of shortcomings. The distance to appropriate treatment and care facilities is far and the necessary drugs are often unavailable. Also, both the knowledge and technology for diagnosing selected diseases is not in place. This study suggests that neurocysticercosis (NCC) plays an important role in this area due to the high number of seizures reported in people, in whom treatment for epilepsy was unsuccessful. Samples taken from a few pigs indicated the presence of Taenia solium, the causal agent of NCC. Furthermore, many of the TBIs are of zoonotic nature and further investigations must be made to begin to assess the burden of these diseases in humans and animals. Environmental changes such as degradation of the vegetation are likely to have an influence on the prevalence of studied diseases and this aspect is being investigated further in other studies. Due to the nature of a cross-sectional study, only limited conclusions can be drawn on the causal relationships of disease prevalence, but the social analysis conducted in this study confirmed the interactions of selected factors related to health and wealth unique for this study area.

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Viol, Milena Araúz [UNESP]. "Detecção de reações cruzadas por Leishmania spp. e Trypanosoma spp. em cães pelo ensaio imunoenzimático indireto, pela reação de imunofluorescência indireta e reação em cadeia de polimerase." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/94717.

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Made available in DSpace on 2014-06-11T19:27:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-18Bitstream added on 2014-06-13T20:16:26Z : No. of bitstreams: 1 viol_ma_me_araca.pdf: 293015 bytes, checksum: bdc10c5bc3d8d20c951f2fc3b6dc7f4e (MD5)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo deste estudo foi detectar reações cruzadas por Leishmania spp. e Trypanossoma cruzi pelo Ensaio Imunoenzimático Indireto (ELISA), pela Reação de Imunofluorescência Indireta (RIFI) e pela Reação em Cadeia da Polimerase (PCR). Assim, foram colhidas 408 amostras sanguíneas de cães domiciliados no município de Araçatuba,SP, de ambos os sexos, de diversas raças e com idade a partir de seis meses. Em relação à Leishmania spp., pela RIFI, 14,95 % (61/408) foram reagentes. A positividade por meio do ELISA, foi de 20,10% (82/408) e pela PCR, 29,66% (121/408), com diferença significativa para o sexo e a idade destes animais (p<0,05). Para Trypanosoma spp., a ocorrência de anticorpos pelo ELISA foi de 10,54% (43/408) e pela PCR, 2,45% (10/408) cães foram positivos. Pela RIFI, 10,29% (42/408) dos animais foram considerados positivos e somente o sexo apresentou diferença significativa (p<0,05). Neste trabalho, constatou-se que 10,54%(43/408) dos animais foram soropositivos por ELISA para Trypanosoma spp., sendo que 79,07%(34/43) obtiveram resultados positivos no diagnóstico molecular para Leishmania spp. e dos 10,29% (42/408) positivos por RIFI, 95,24% (40/42) dos cães confirmaram a infecção por este parasita. Por meio dos resultados obtidos, pode-se inferir que foram evidenciadas reações cruzadas nos ensaios sorológicos para ambos os protozoários, nos animais analisados neste trabalho
The aim of this study was to detect cross-infection by Leishmania spp. and Trypanosoma spp. by indirect immunosorbent assay (ELISA), by Indirect Immunofluorescence (IFA) and by the Polymerase Chain Reaction (PCR). Thus, blood samples were collected from 408 domestic dogs of both sexes, different races and ages from six months. For Leishmania spp. by IFA, 14.95% (61/408) were positive. Positive by ELISA, was 20.10% (82/408), and PCR 29.66% (121/408), with significant difference for sex and age of animals (p <0.05). For Trypanosoma spp., the occurrence of antibodies by ELISA, was 10.54% (43/408), and PCR, 2.45% (10/408) dogs were positive. By IFA, 10.29% (42/408) of the animals were considered positive and only sex was significant difference (p <0.05). In this work it was found that 10.54% (43/408) animals were seropositive by ELISA for Trypanosoma spp., 79.07% (34/43) had positive results in molecular diagnostic for Leishmania spp. and 10.29% (42/408) positive by IFA, 95.24% (40/42) dogs confirmed the infection by this parasite. Through the results obtained can be inferred that cross-infection were observed by both protozoa in animals of this paper

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Viol, Milena Araúz. "Detecção de reações cruzadas por Leishmania spp. e Trypanosoma spp. em cães pelo ensaio imunoenzimático indireto, pela reação de imunofluorescência indireta e reação em cadeia de polimerase /." Araçatuba : [s.n.], 2011. http://hdl.handle.net/11449/94717.

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Orientador: Katia Denise Saraiva Bresciani
Banca: Renato Andreotti e Silva
Banca: Valéria Marçal Felix de Lima
Resumo: O objetivo deste estudo foi detectar reações cruzadas por Leishmania spp. e Trypanossoma cruzi pelo Ensaio Imunoenzimático Indireto (ELISA), pela Reação de Imunofluorescência Indireta (RIFI) e pela Reação em Cadeia da Polimerase (PCR). Assim, foram colhidas 408 amostras sanguíneas de cães domiciliados no município de Araçatuba,SP, de ambos os sexos, de diversas raças e com idade a partir de seis meses. Em relação à Leishmania spp., pela RIFI, 14,95 % (61/408) foram reagentes. A positividade por meio do ELISA, foi de 20,10% (82/408) e pela PCR, 29,66% (121/408), com diferença significativa para o sexo e a idade destes animais (p<0,05). Para Trypanosoma spp., a ocorrência de anticorpos pelo ELISA foi de 10,54% (43/408) e pela PCR, 2,45% (10/408) cães foram positivos. Pela RIFI, 10,29% (42/408) dos animais foram considerados positivos e somente o sexo apresentou diferença significativa (p<0,05). Neste trabalho, constatou-se que 10,54%(43/408) dos animais foram soropositivos por ELISA para Trypanosoma spp., sendo que 79,07%(34/43) obtiveram resultados positivos no diagnóstico molecular para Leishmania spp. e dos 10,29% (42/408) positivos por RIFI, 95,24% (40/42) dos cães confirmaram a infecção por este parasita. Por meio dos resultados obtidos, pode-se inferir que foram evidenciadas reações cruzadas nos ensaios sorológicos para ambos os protozoários, nos animais analisados neste trabalho
Abstract: The aim of this study was to detect cross-infection by Leishmania spp. and Trypanosoma spp. by indirect immunosorbent assay (ELISA), by Indirect Immunofluorescence (IFA) and by the Polymerase Chain Reaction (PCR). Thus, blood samples were collected from 408 domestic dogs of both sexes, different races and ages from six months. For Leishmania spp. by IFA, 14.95% (61/408) were positive. Positive by ELISA, was 20.10% (82/408), and PCR 29.66% (121/408), with significant difference for sex and age of animals (p <0.05). For Trypanosoma spp., the occurrence of antibodies by ELISA, was 10.54% (43/408), and PCR, 2.45% (10/408) dogs were positive. By IFA, 10.29% (42/408) of the animals were considered positive and only sex was significant difference (p <0.05). In this work it was found that 10.54% (43/408) animals were seropositive by ELISA for Trypanosoma spp., 79.07% (34/43) had positive results in molecular diagnostic for Leishmania spp. and 10.29% (42/408) positive by IFA, 95.24% (40/42) dogs confirmed the infection by this parasite. Through the results obtained can be inferred that cross-infection were observed by both protozoa in animals of this paper
Mestre

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Hoste, Christian. "Elevage et trypanosomiase animale africaine." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37605971k.

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Mjihdi, Abdelkarim. "Capacité de reproduction de la souris et infection aiguë par Trypanosoma cruzi." Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211065.

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Trypanosoma cruzi est un parasite protozoaire à multiplication intracellulaire, agent de la maladie de Chagas, infectant 16 à 18 millions de personnes en Amérique latine. Il peut être transmis de la mère infectée au fœtus dans 2 à 10 % des cas, mais ses autres effets sur la gestation ont été peu étudiés. Par ailleurs, les cytokines ont des effets sur la gestation. Certaines d’entre elles, comme l’interleukine-1, l’IL-4, l’IL-5, l’IL-10, le GM-CSF et le TGF-b2, sont bénéfiques pour la gestation, tandis que d’autres, comme l’IL-2, l’IL-12, l’IFN-g et le TNF-a ont des effets nocifs sur celle-ci. L’impact de l’infection à T. cruzi, stimulant la production de TNF-a et d’IFN-g, sur l'implantation et la croissance fœtale n’a pas été étudié.

Le but de notre travail était d’étudier les effets de l’infection aiguë à T. cruzi sur la capacité de reproduction de la souris. Nous avons ainsi évalué les effets de cette infection sur la fertilité, le développement et la viabilité des fœtus de souris et le rôle de l’IFN-g et du TNF produits au cours de l’infection sur le développement de la gestation.

Nous avons montré que l’infection aiguë à T. cruzi :i) diminue la capacité de reproduction de la souris ;ii) provoque une mortalité fœtale massive précoce (résorptions), tardive et néonatale associée à un retard de croissance intra-utérin, et ce, iii) en dehors de toute transmission congénitale du parasite.

Par ailleurs nos travaux montrent que la mortalité fœtale/néonatale est associée à une invasion parasitaire massive du placenta qui présente d’importantes lésions à type d’infiltrats inflammatoires, de nécrose ischémique, de dépôts de fibrine et de thromboses vasculaires. Nous avons noté qu’il existe une relation inverse entre la charge parasitaire des unités utéro-placentaires et la viabilité du conceptus, suggérant que ces lésions placentaires contribuent à la mortalité fœtale en limitant les échanges materno-fœtaux.

Enfin, nous avons également étudié le rôle de cytokines abortogènes comme le TNF et l’IFN-g, produites abondamment pendant l’infection aiguë de la souris par T. cruzi. Les taux sanguins maternels d’IFN-g étaient augmentés au 9ième mais pas aux 17ième et 19ième jours de gestation, alors que les taux de TNF sanguin et la production placentaire de cette cytokine augmentaient aux 17ième et 19ième jours de gestation. Afin d’évaluer le rôle de ces deux cytokines dans la mortalité fœtale, des souris ont été traitées par la pentoxifylline, pour inhiber la transcription du gène de TNF-a et diminuer la production d’IFN-g. Ces souris montraient une réduction de la mortalité fœtale à mi-gestation, associée à une diminution de la production du TNF placentaire, sans modifications des taux systémiques et sans effets sur l’IFN-g, suggérant la contribution du TNF dans la mortalité fœtale associée à l’infection aiguë par T. cruzi.

En conclusion, notre travail montre que l’infection aiguë à Trypanosoma cruzi exerce un effet particulièrement néfaste sur la capacité de reproduction et le développement de la gestation chez la souris et que les lésions placentaires liées à l’infection et la production de TNF par le placenta infecté contribuent à cet effet.

Doctorat en sciences biomédicales
info:eu-repo/semantics/nonPublished

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Amadou, Ibrahim Ahamed. "Economics of animal trypanosomiasis control in the Adamawa Plateau, Cameroon." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319241.

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Guegan, Fabien. "Caractérisation des sialidases chez le parasite Trypanosoma vivax : rôle dans l’anémie." Thesis, Bordeaux 2, 2010. http://www.theses.fr/2010BOR21775/document.

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La trypanosomiase animale africaine (TAA) est une pathologie qui sévit en Afrique sub-saharienne et qui représente un obstacle majeur à l’élevage du bétail et à la production agricole. Cette pathologie est causée principalement par les parasites T. congolense et T. vivax. Elle affecte le bétail, les animaux domestiques et sauvages, sur un territoire de 10 millions de km2 où ces animaux cohabitent avec l’insecte vecteur, la mouche Tsé-Tsé. L’infection du bétail par ces parasites provoque une anémie sévère pouvant entraîner la mort de l’animal. Dans ce contexte, nous nous sommes intéressés à l’étude des mécanismes impliqués dans le développement de l’anémie lors de l’infection de l’animal par T. vivax. Pour cela, nous avons développé un modèle murin d’infection par T. vivax. Nous avons démontré que l’infection à T. vivax induit d’importantes modifications des acides sialiques présents à la surface des érythrocytes. De plus, nous avons établi un système expérimental « ex-vivo » qui nous a permis de montrer que l’anémie observée au cours de l’infection était dépendante du mécanisme d’érythrophagocytose. Les modifications en acides sialiques des érythrocytes constitueraient un signal de reconnaissance des érythrocytes par les cellules phagocytaires de l’hôte. Par ailleurs, nous avons mis au point des conditions de culture in vitro pour tous les stades parasitaires de T. vivax et T. congolense afin de développer des outils de génomique fonctionnelle. Ces avancées nous ont notamment permis d’identifier des enzymes de type sialidase et trans-sialidase et de détecter les activités enzymatiques correspondantes dans les formes infectieuses de ces parasites. Nous avons exprimé des trans-sialidases recombinantes et démontré qu’elles étaient capables de reproduire in vitro certaines des caractéristiques pathologiques définies in vivo : modifications en acides sialiques des érythrocytes et augmentation de l’érythrophagocytose. Par conséquent, ces travaux ont permis pour la première fois de mettre en évidence un lien entre l’expression des sialidases et trans-sialidases chez le parasite T. vivax et le développement de l’anémie au cours de la TAA
African animal trypanosomiasis (AAT) is a parasitic disease occurring in sub-Saharan Africa. It impairs livestock development and agricultural production. This disease is mainly caused by T. congolense and T. vivax parasites and is present in livestock, domestic and wild animals, covering an area of over a 10 millions km2, that is known as the Tsé-Tsé fly belt. These infections cause severe anaemia leading to animal death in most cases. In this context, we were interested in unravelling the mechanisms responsible for anaemia caused by T. vivax infection. We developed a murine model for T. vivax infection and our data pointed out important sialic acid modifications of the mouse erythrocyte surface during infection. Additionally, an ex-vivo experimental model was established which proved that anaemia associated with infection depends on erythrophagocytosis. Consequently, we propose that sialic acid modifications associated with infection are involved in the erythrophagocytosis mechanism. Furthermore, in order to develop genetic tools we established in vitro culture conditions for all parasite forms of T. vivax and T. congolense. Parasite cultivation allowed the detection of sialidase and trans-sialidase activity and identifies the presence and function of these proteins in the mammalian form of the parasite. Moreover, trans-sialidase recombinant proteins reproduced some of the T. vivax infection characteristics such as sialic acid modification and increased erythrophagocytosis. Consequently, this work provides the first evidence that links the expression of sialidases and trans-sialidases in T. vivax with the development of anemia during AAT

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Olaniyan, Oluwashola. "Vectors and transmission routes of animal trypanosomiasis on the Jos Plateau north central Nigeria." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/23398.

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Tsetse flies, Glossina species, are the biological vectors of Trypanosoma species which cause animal African trypanosomiases (AAT) in livestock (especially cattle) in sub-Saharan Africa. This disease is often fatal without treatment and negatively impacts on rural, agricultural and economic development. On the Jos Plateau, north central Nigeria, AAT was historically of little significance due to the presumed absence of tsetse and Fulani pastoralists were encouraged to settle there. But over the last 30 years, the disease has become widespread and highly prevalent in the area. This has been attributed to the expansion of tsetse on the plateau, frequent migrations of cattle to areas with higher tsetse densities and the presence of other biting flies which serve as mechanical vectors. In the current study, the presence and abundance of tsetse was determined in selected villages using biconical tsetse trap surveys. The low number of flies trapped suggests that tsetse expansion has been very limited within the plateau but the fact that trypanosome DNA was present in over half of these flies implicates them in AAT transmission. The migration of a herd of cattle was also tracked and during the period, blood samples were collected from the cattle and examined for trypanosomes using molecular techniques. Despite prophylactic treatment and deltamethrin sprays, results showed that a significant proportion of the animals (52%) had become infected with T. vivax over the migration period. Tsetse flies (G. palpalis) were also slightly more abundant in some of parts of the migration area. Potential mechanical vectors (Stomoxys spp. and Tabanidae) were trapped and results obtained from the examination of their mouthparts for trypanosomes indicate their involvement in transmission. However, it is difficult to make any definite conclusions about their overall contribution which is thought to be minimal and more studies are needed to clarify their significance. It is concluded that trypanosomiasis risk from tsetse on the Jos Plateau is currently low and seasonal migration appears to be the main driver of AAT transmission by exposing cattle to more tsetse for longer periods. Other biting flies may play a limited role which remains undetermined. Continued monitoring of cattle and tsetse across the plateau over the next few years is important and the careful use of trypanocides and insecticide treated cattle is recommended as an appropriate control strategy.

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Santirso-Margaretto, Cristina. "The epidemiology of African animal trypanosomiasis in transhumant herds of the sub-humid zone of Nigeria." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25873.

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Nigeria recently became the leading economy in Sub-Saharan Africa with a total GDP of 522.64 billion of US dollars (Tradingeconomics.com). As GDP increases, population rises and food demand intensifies. Within this context it is of critical importance to achieve food security. However, Nigeria heavily relies in exportations in order to meet the growing food demand, especially of meat products, a situation which is not desirable. The livestock industry, although one of the largest in Sub-Saharan Africa, still constrained by several endemic livestock diseases which result in annual economic loses for value of 140 million of US dollars (Fadiga et al., 2013). Within this group, bovine and porcine trypasosomiasis alone has been estimated to be responsible for 50 million of US dollars in economic loses in Nigeria (Fadiga et al., 2013). However, the real epidemiological situation, and hence the possibility of developing a rational control programme, remains largely unknown across the country due to the absence of large epidemiological studies. Majority of the trypanosomiasis research studies in Nigeria employ the Haematocrit technique or the Buffy coat technique and Giemsa stain as a diagnostic method. These techniques possess a high specificity but a much lower sensitivity than the molecular method employed in this research study. In fact, better epidemiological studies employing molecular techniques have been conducted in recent times such (Majekodumni et al., 2013a; Takeet et al., 2013) and results displayed much higher trypanosomiasis prevalence than previously detected by microscopy. In many sub-Saharan countries the majority of national livestock herds are owned by mobile communities; however, the trypanosome status of cattle owned by mobile pastoralist communities have been less thoroughly studied when compared to those of sedentary livestock keepers. In this doctoral work, the epidemiology of trypanosomiasis was studied, in transhumant herds located in two different Nigerian enclaves: the Kachia grazing reserve and the Jos Plateau, both located in North-central Nigeria. Within Kachia, the ecology appears to determine the presence of infection with a spatially differentiated distribution of the detected trypanosome species being observed across the reserve that appears not to be related to the migration of livestock. While upon the Jos Plateau, the current reduction in trypanosome prevalence suggests an abrupt change in the trypanosome infection rates in this part of the country. The hypothesis established in this doctoral work is that these epidemiologically different scenarios are the result of land pressures that have ultimately resulted in the habitat destruction of the vector. Longitudinal data was also collected in order to assess the effectivity of different formulations of synthetic pyrethroids for the combined control of trypanosomiasis and tick-borne diseases. Insecticide treated cattle represents at the moment the best long-term and cost-effective method for the control of the vector responsible for the transmission of trypanosomiasis, the tsetse fly. Since no data exist about the efficacy of the insecticide or the compliance of the pastoralist population with its application under migratory conditions, its performance was assessed in this doctoral work. In addition, animal health outcomes were monitored to stablish the possible relationship between clinical symptoms and disease outcome and socio-economic data relevant for the dynamics of disease such as migration trends, husbandry practices, awareness and administered treatment has been also analysed. The compiled information of this data will establish the risk associated with contracting the disease and provide further indications for the control of African bovine trypanosomiasis in the specific context of transhumant pastoral systems of sub-humid sub-Saharan African.

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Capelle, Nicolas. "Procédés de synthèses de dérivés hétérocycliques de la phénanthridine utilisés en santé animale." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30067.

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Nous avons étudié le procédé multiétapes de synthèse de deux trypanosomicides dérivés de la phénanthridine, l'Homidium et l'Isométamidium, utilisés en santé animale, dans le but d'acquérir la connaissance chimique et analytique sur tout le procédé. Une étape de quaternisation de la phénanthridine, qui posait un important problème de sécurité, a été améliorée au niveau du rendement et du contrôle de la réaction. La dernière étape de synthèse a été maîtrisée et optimisée notamment grâce à un plan d'expériences. Pour éviter un procédé de séparation par relargage long et laborieux, nous avons mis au point un nouveau procédé de purification de l'Isométamidium par nanofiltration, qui est un procédé innovant de filtration sur membrane en chimie fine. Enfin nous avons imaginé et réalisé complètement une nouvelle voie de synthèse des sels de phénanthridinium, qui évite l'étape de quatemisation des phénanthridines. La stratégie de synthèse utilise comme étape clé une réaction de couplage de type Suzuki
We studied the multistep synthetic process of two phenanthridine derivatives, namely the trypanosomicides Homidium and Isometamidium used in animal health, with the purpose to acquire the chemical and analytical knowledge on all the process. A step of quaternisation of phenanthridine, which was hazardous under previous conditions, was improved with an increase of the yield under safe regulation of the reaction. The last step of synthesis was controlled and optimized especially thanks to an experimental design. For avoiding a long and tedious separation procedure of salting out, we developed a novel and original process of purification of Isometamidium by nanofiltration, which is a process of filtration on membrane that could be extended to fine chemicals. Finally we designed and carried out a new synthetic route to phenanthridinium salts, what avoids the step of quaternisation of phenanthridine. The strategic step of this synthesis used the Suzuki's coupling reaction

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Duvallet, Gérard. "Trypanosomoses humaine et animale en Afrique de l'Ouest : recherches épidémiologiques et immunoparasitologiques." Paris 11, 1987. http://www.theses.fr/1987PA112256.

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Les trypanosomoses sont des maladies parasitaires dues à des protozoaires flagellés du genre Trypanosoma. En Afrique de l'Ouest, elles sont transmises à l'homme et aux animaux par des insectes hématophages, en particulier les glossines. La trypanosomose humaine africaine (THA) à Trypanosoma gambiense sévit sur un mode endémo-épidémique et, non traitée, se termine par une méningoencéphalite mortelle. L'auteur décrit l’introduction et l'évaluation des techniques immunologiques, en particulier l’immunofluorescence indirecte, au cours des campagnes de dépistage dans les foyers des pays membres de l'OCCGE. Des techniques parasitologiques plus sensibles, en particulier la centrifugation en tubes capillaires et la filtration/centrifugation sur mini-colonnes de DEAE-cellulose, ont été évaluées pour obtenir un diagnostic de certitude. L'épidémiologie de la THA a été étudiée dans les foyers reviviscents de Bouaflé et de Vavoua en Côte d'Ivoire. Le foyer sans glossines d’OUAHIGOUYA au Burkina Faso, situé au nord de la limite de répartition des glossines est décrit. Enfin, une stratégie de dépistage est proposée, pour l’Afrique de l’Ouest, afin d’être incluse dans une stratégie globale comprenant lutte anti-vectorielle, dépistage et traitement des malades. La découverte récente d’un réservoir animal potentiel de trypanosomes pathogènes pour l'homme rend illusoire l'idée d'éradiquer cette maladie. La trypanosomose animale est un obstacle majeur au développement de l'élevage en Afrique Tropicale. Les potentialités des zones de savanes humides sont telles qu'une élimination de cette maladie permettrait de répondre à la demande croissante en produits d'élevage. L'impossibilité d'éradiquer les glossines sur l’ensemble de ces zones et l'apparition de chimiorésistance des trypanosomes aux médicaments trypanocides disponibles, font des bovins trypanorésistants de l'ouest-africain une solution d'avenir pour le développement de l'élevage. Dans le cadre des recherches du CRTA sur la trypanotolérance, l'auteur a isolé un répertoire de Trypanosoma brucei brucei et étudié son expression chez des animaux sensibles et résistants.

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Paixão, Mirian dos Santos. "Análise espacial e detecção de tripanosomatídeos em animais de produção de região endêmica para leishmaniose visceral." Botucatu, 2017. http://hdl.handle.net/11449/151274.

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Orientador: Simone Baldini Lucheis
Resumo: A família Trypanosomatidae é composta por protozoários flagelados da ordem Kinetoplastidae. Os protozoários do gênero Trypanosoma, causadores das tripanossomíases e gênero Leishmania, causadores das leishmanioses, são os parasitos de maior interesse médico e veterinário As tripanossomíases são causadas por diferentes espécies, dentre elas: Trypanosoma cruzi, Trypanosoma. theileri, Trypanosoma equiperdum, Trypanosoma evansi e Trypanosoma vivax, sendo os três últimos de maior importância para os animais de produção, causando prejuízos econômicos para o setor agropecuário. Com o objetivo de avaliar a ocorrência de tripanosomatídeos no municipío de Bauru-SP, região endêmica para leishmaniose, foram avaliados 200 animais, sendo 100 bovinos (Bos taurus) e 100 equídeos (Eqqus spp.), procedentes de áreas urbanas e periurbanas do município. Para entender a distribuição de fatores de riscos na análise espacial, avaliou-se fatores epidemiológicos das leishmanioses, relacionados a seu diagnóstico nos animais de produção avaliados e também em cães e em humanos em diferentes bairros do município de Bauru, visando sua compreensão e integrá-las a estratégias de controle da doença. O diagnóstico dos animais foi baseado em técnicas parasitológicas: esfregaço sanguíneo e hemocultura; sorológicas: Reação de Imunofluorescência Indireta (RIFI) e Enzyme Linked Immunosorbent Assay (ELISA) e moleculares: Reação em Cadeia da Polimerase (PCR) e seqüenciamento. Não foram encontradas formas sugestivas de... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor

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Paixão, Mirian dos Santos [UNESP]. "Análise espacial e detecção de tripanosomatídeos em animais de produção de região endêmica para leishmaniose visceral." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151274.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A família Trypanosomatidae é composta por protozoários flagelados da ordem Kinetoplastidae. Os protozoários do gênero Trypanosoma, causadores das tripanossomíases e gênero Leishmania, causadores das leishmanioses, são os parasitos de maior interesse médico e veterinário As tripanossomíases são causadas por diferentes espécies, dentre elas: Trypanosoma cruzi, Trypanosoma. theileri, Trypanosoma equiperdum, Trypanosoma evansi e Trypanosoma vivax, sendo os três últimos de maior importância para os animais de produção, causando prejuízos econômicos para o setor agropecuário. Com o objetivo de avaliar a ocorrência de tripanosomatídeos no municipío de Bauru-SP, região endêmica para leishmaniose, foram avaliados 200 animais, sendo 100 bovinos (Bos taurus) e 100 equídeos (Eqqus spp.), procedentes de áreas urbanas e periurbanas do município. Para entender a distribuição de fatores de riscos na análise espacial, avaliou-se fatores epidemiológicos das leishmanioses, relacionados a seu diagnóstico nos animais de produção avaliados e também em cães e em humanos em diferentes bairros do município de Bauru, visando sua compreensão e integrá-las a estratégias de controle da doença. O diagnóstico dos animais foi baseado em técnicas parasitológicas: esfregaço sanguíneo e hemocultura; sorológicas: Reação de Imunofluorescência Indireta (RIFI) e Enzyme Linked Immunosorbent Assay (ELISA) e moleculares: Reação em Cadeia da Polimerase (PCR) e seqüenciamento. Não foram encontradas formas sugestivas de protozoários em esfregaço sanguíneo, mas a análise de hemocultura de sete animais permitiu a visualização desses protozoários. Às técnicas sorológicas para Leishmania spp., 25% dos bovinos e 16% dos eqüídeos foram reagentes à RIFI e 24% dos equídeos e 6% dos bovinos reagentes ao ELISA. A PCR foi realizada a partir de amostras de sangue, hemocultura, suabes conjuntivais e ectoparasitos, com primers que amplificam a região ITS e HSP70. A partir de amostras de sangue, 23% dos bovinos e 6% dos eqüídeos foram positivos e sete amostras de hemocultura de bovinos foram positivas, com pelo menos um dos primers. As amostras de ectoparasitos e suabes não apresentaram positividade à PCR. Em amostras de bovinos positivas à PCR foram identificadas espécies do gênero Leishmania infantum, Leishmania donovani e Trypanosoma theileri e em amostras de eqüídeos, foram identificadas espécie do gênero Leishmania: Leishmania donovani. Os resultados obtidos às provas parasitológicas, sorológicas e/ou moleculares sugerem a presença de tripanosomatídeos em animais de produção do município no Bauru-SP. No presente estudo, pela análise espacial, sugere-se o papel de proteção dos animais de produção para a ocorrência de leishmaniose em humanos.
The family Trypanosomatidae is composed of flagellate protozoa of the order Kinetoplastida, divided into 10 genera. The Trypanosoma protozoa, which cause trypanosomiasis and Leishmania genus, which cause leishmaniosis, are the parasites of major medical and veterinary interest. Trypanosomiasis is caused by different species, among them: Trypanosoma cruzi, T. theileri, T. equiperdum, T . evansi and T. vivax, which affect production animals, causing economic damages to the agricultural sector. In order to evaluate the occurrence of trypanosomatids in the municipality of Bauru-SP, a region endemic for leishmaniosis, the present study evaluated 200 animals, 100 cattle (Bos taurus) and 100 equidae (Eqqus spp.) from urban and peri-urban areas of the municipality. In the spatial analysis, in order to understand the distribution of risk factors, we evaluated the epidemiological factors of leishmaniasis, related to its diagnosis in the studied animals, in dogs and in humans as well, from different districts of Bauru city, aiming a better comprehension and the strategies for the control of this disease. The diagnosis was based on parasitological techniques: blood smear and blood culture; serological tests: Immunofluorescence Antibody Test (IFAT) and Enzyme Linked Immunosorbent Assay (ELISA); and molecular: Polymerase Chain Reaction (PCR) and sequencing. No suggestive forms of protozoa were found in blood smears, but the blood culture analysis of seven animals allowed visualization of these protozoa. To the serological techniques for Leishmania spp., 25% of the cattle and 16% of the equines were reactive to IFAT and 24% of the equines and 6% of the cattle reactive to ELISA. PCR was performed from blood samples, blood cultures, conjunctival swabs and ectoparasites, with primers from the ITS and HSP70 region. From blood samples, 23% of cattle and 6% of equines were positive and seven samples of bovine blood culture were positive, with at least one of the primers. Samples of ectoparasites and swabs showed no PCR positivity. Specimens of the genus Leishmania infantum, Leishmania donovani and Trypanosoma theileri were identified in specimens of PCR positive bovines, and species of the genus Leishmania: Leishmania donovani were identified in equine samples. The results obtained for the parasitological, serological and / or molecular tests suggest the presence of trypanosomatids in animals of the municipality of Bauru-SP. In this study, by the spatial analysis, the role of protection of the production animals for the occurrence of leishmaniosis in humans is suggested.
FAPESP: 2014/15808-6

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Amevigbe, Dotse Dzabli Martin. "Les anticorps anti-cérébrosides au cours de la trypanosomose humaine africaine et expérimentale du mouton (ovis aries)." Limoges, 1992. http://www.theses.fr/1992LIMOA101.

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Hamill, Louise Claire. "Molecular epidemiology of trypanosomiasis in Ugandan cattle during the Stamping Out Sleeping Sickness control programme, 2006-2008." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/12257.

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Over the past two decades movement of cattle towards the north of Uganda has enabled the Trypanosoma brucei rhodesiense focus in south-eastern Uganda to spread into previously unaffected districts. This thesis brings together important epidemiological data regarding the impact of mass cattle drug treatment on the point prevalence of several different species of trypanosome in a newly endemic area of human sleeping sickness. Crucially the findings illustrate mass drug treatment is effective in reducing the prevalence of T. b. rhodesiense in cattle, thus minimising the reservoir potential of these animals in the epidemiology of human disease. During 2006 a control programme was launched to halt the northward spread of this zoonotic parasite. This programme, entitled ‘Stamping Out Sleeping Sickness’ (SOS) proposed to reduce the prevalence of Human African Trypanosomiasis (HAT) in the newly affected districts by reducing the prevalence of this parasite in the main animal reservoir of infection – domestic cattle. Cattle were mass treated using trypanocides to clear infections. Previous work demonstrated the prevalence of T. brucei s. l. and T. b. rhodesiense in cattle was higher in the districts of Dokolo and Kaberamaido than in the other SOS intervention districts (Selby 2011). To determine whether animals in these areas were also exposed to pathogenic cattle trypanosomes samples were screened for the presence of T. vivax and T. congolense savannah using PCR. Chapter three of this thesis determined the prevalence of these trypanosomes in cattle in these districts. Before treatment had taken place the prevalence of T. vivax was 2% (4/200, 95% CI 3.57 – 0.12%) in Dokolo and 7.3% (21/310, 95% CI 10.17 - 4.24 %) in Kaberamaido. The prevalence of T. congolense savannah at baseline was 3.5% (7/200, 95% CI 7.08–1.42 %) in Dokolo and 9.1% (21/230, 95% CI13.6–5.7 %) in Kaberamaido. Monitoring was conducted three, nine and 18 months post treatment and both pathogens were detected at all time points. The impact the treatment had on point prevalence varied by trypanosome species and between the two districts. Several clusters of villages in Dokolo and Kaberamaido continued to report cases of HAT after the initial SOS intervention due in part to their proximity to livestock markets (Batchelor et al., 2009). In 2008 re-treatment of these ‘high risk’ areas was undertaken. Monitoring was performed before and six months after treatment. Cattle blood samples were collected at 20 village sites from ten ‘case-positive villages’ (from which human sleeping sickness cases had been reported six months prior to June 2007) and from ten ‘case-negative villages’ (no reported human sleeping sickness cases six months prior to June 2007). These samples were screened for all of the aforementioned trypanosomes using species specific PCR protocols. Chapter five details the results of this screening, and assessed whether re-treatment in Dokolo and Kaberamaido was effective in reducing the prevalence of trypanosomiasis. The re-treatment had a dramatic effect, significantly reducing the point prevalence of overall trypanosomiasis in the 20 villages screened from 38.1% (95% CI = 40.5 – 35.79%) at baseline to 26.9% (95% CI 28.96 – 24.97, p < 0.0001) at six months. Looking at each species separately, point prevalence of three out of four detected species of trypanosome fell significantly, including T. b. rhodesiense, which was reduced to 25% of its baseline prevalence. Finally the two SOS treatment cycles were compared both statistically and spatially with emphasis on trends at village level and the occurrence of mixed infections.

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Boda, Caroline. "Contribution des modèles expérimentaux dans l'étude des trypanosomoses africaines." Limoges, 2005. http://aurore.unilim.fr/theses/nxfile/default/7fa54944-6101-4979-85d4-313a4eb37e0c/blobholder:0/2005LIMO310A.pdf.

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La maladie du sommeil ou trypanosomose humaine africaine (THA) est une pathologie réémergente qui cause un véritable problème de santé publique. La compréhension de la physiopathologie nécessaire à la mise en place de nouvelles thérapeutiques est limitée et les traitements actuels sont les mêmes depuis une trentaine d'années. C'est pourquoi il est indispensable de mettre au point des modèles expérimentaux animaux de la maladie afin de disposer d'un support d'étude. Notre travail de thèse a permis de tester le mégazol dans le traitement de la trypanosomose chez le mouton infecté par Trypanosoma brucei brucei. Les résultats de l'essai thérapeutique et les paramètres pharmacocinétiques mesurés chez le mouton sain ont permis de comprendre que le mégazol administré par voie orale permet d'obtenir une rémission sans rechute des animaux infectés en stade I, à condition que l'absorption digestive s'effectue correctement. Le mégazol a alors été testé chez des singes verts infectés par T. B. Gambiense afin d'optimiser la posologie efficace. Les résultats obtenus sont encourageants et mériteraient d'être approfondis par l'étude des dérivés non mutagènes du mégazol, récemment synthétisés. Nous avons également testé l'efficacité de l'association DFMO-nifurtimox à doses réduites chez un modèle de vervets infectés. Seule une efficacité partielle après traitement oral pendant 8 ou 15 jours a pu être obtenue et devra être expliquée par une étude pharmacocinétique ultérieure. Au cours de notre travail de thèse, nous avons également testé l'activité trypanocide du bleu de méthylène. Cette molécule s'est révélée être active in vitro sur deux souches de trypanosomes africains, en revanche, aucune efficacité n'a pu être obtenue chez la souris infectée et traitée per os ou par voie intra-péritonéale. Plusieurs hypothèses sont émises et mériteraient d'être vérifiées par des études supplémentaires. D'autre part, nous avons essayé de trouver de nouveaux critères de stade plus précoces et plus spécifiques. Pour cela, la technique de cytométrie en flux a été utilisée chez l'homme afin de s'assurer de la faisabilité et de l'intérêt de cette méthode dans les études des THA. Nous avons ensuite utilisé cette technique chez le vervet pour valider un modèle d'étude immunologique de la maladie. Nous avons alors cherché par cytométrie en flux les modifications significatives des sous-types lymphocytaires susceptibles d'aboutir à de nouveaux critères diagnostiques. Les résultats ont mis en évidence une augmentation significative des lymphocytes B dans le liquide céphalo-rachidien au cours de l'infection. Le vervet semblerait constituer un bon modèle pour approfondir ces résultats et pour la mise au point d'un test diagnostic de terrain
Human African trypanosomiasis (HAT) or sleeping sickness is a re-emerging disease responsible for a major public health problem. Knowledges about its physiopathology are necessary to find out new therapeutics but few studies are available. There is an urgent need to work with new experimental models to test trypanocidal activity of new drugs. In this work, we tested first megazol in Trypanosoma brucei brucei-infected sheep and its pharmacokinetics in uninfected sheep. Results showed megazol is efficient to treat stage I of trypanosomiasis in sheep if oral absorption occurs properly but this parameter seem to be very variable. Then, megazol was tested in T. B. Gambiense-infected African green monkeys in order to find out the optimal dosing. The results should be completed by further studies with more animals and with non mutagenic megazol derived compounds. Combination of two trypanocidals, DFMO and nifurtimox, bas been tested at low dosing in infected African green monkey. DFMO associated to nifurtimox given per os during 8 or 15 days couldn't cure the all animals. These results should be explained by a pharmacokinetics study of the combination. In a further study, we tested trypanocidal activity of methylene blue in vitro and in vivo. We obtained IC50 suggesting methylene blue could be active on trypanosomal infections. However, methylene blue given per os or intra-peritonealy couldn't cure infected mice. Several hypothesis are discussed and deserve to be verified. In an other hand, we tried to find out new criteria more precoce and specific for the stage diagnostic. We first adapted the method of flow cytometry to analyse blood and cerebrospinal fluid of infected patients and ensure its utility to study sleeping sickness. Then, we reproduce the experiment in infected African green monkeys to analyse the lymphocytes subset in blood and cerebrospinal fluid every two weeks. Results showed an increase in lymphocytes B during the disease course. African green monkey could be a good immunological model of the disease to precise these first results and to develop a field test for stage diagnosis

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Ammar, Zeinab. "Caractérisation de l' interaction entre les trypanosomes africains et les cellules endothéliales : activation, inflammation et rôle des trans-sialidases." Thesis, Bordeaux 2, 2013. http://www.theses.fr/2013BOR22057/document.

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La trypanosomose est la maladie parasitaire la plus dévastatrice en Afrique, et affecte à la fois les hommes et le bétail. Vu l’inefficacité des stratégies de contrôle actuelles, une stratégie alternative dite “anti-maladie” a été proposée dans le cadre de la trypanosomose animale. Elle vise à neutraliser les effets de la maladie plutôt qu’à éliminer le parasite. Une telle stratégie nécessite une meilleure compréhension du développement de la pathologie ainsi qu’une caractérisation détaillée des facteurs de virulence impliqués. Dans ce contexte, nous nous sommes intéressés à l’étude de l’interaction hôte/pathogène entre les trypanosomes Africains et l’endothélium de l’hôte mammifère. En comparant quatre espèces différentes de trypanosomes Africains, nous avons montré que leurs capacités d’activation des cellules endothéliales étaient distinctes. Nous avons clairement démontré que T. congolense, T. vivax et T. b. gambiense activent les cellules endothéliales via la voie de NF-ƘB, alors que T. b. brucei est incapable d’activer cette voie. Cette activation a induit une résponse pro-inflammatoire in vitro et in vivo, ce qui souligne l’importance de ce mécanisme dans le développement de la maladie. Pour la première fois, nous avons identifié une activité sialidase chez le parasite de l’homme T. brucei gambiense, et nous avons démontré que les trans-sialidases trypanosomales sont les médiateurs de cette activation endothéliale et de la réponse inflammatoire consécutive, et ceci à la fois chez les trypanosomes africains d’homme et d’animaux. De plus, nous avons montré que l’activation endothéliale implique l’activité lectin-like des trans-sialidases et non pas l’activité catalytique, ainsi que des récepteurs sialylés sur la surface endothéliale. En conclusion, ce travail a apporté des avancées considérables dans la compréhension de la relation hôte/pathogène et a permis de désigner les sialidases comme un facteur de virulence central dans le dialogue intermoléculaire durant les trypanosomoses, en faisant une cible de choix pour le vaccin « anti-maladie »
Trypanosomiasis remains by far the most devastating parasitic disease in Africa affecting both humans and livestock. The current control strategies being not efficient, an alternative “anti-disease” strategy aiming to neutralize the pathological effects of the parasite rather than to eliminate it, was proposed. Therefore, it is essential to understand the development of pathogenesis and characterize the involved pathogenic factors. In this context, we wanted to elucidate the host-pathogen interaction between the African trypanosomes and the mammalian host endothelium. By comparing four different trypanosomes species, we showed that they displayed distinct capacities for activation of endothelial cells. We clearly demonstrated that T. congolense, T. vivax and T. b. gambiense activate the endothelial cells via the NF-ƘB pathway, but not T. b. brucei. This activation caused a pro-inflammatory response in vitro and in vivo, showing the importance of this mechanism in the development of pathogenesis. For the first time, we identified sialidase activity in the human parasite T. brucei gambiense, and demonstrated that the trypanosomal trans-sialidases are the mediators of this endothelial activation and its consequent inflammatory response, for both human and animal trypanosomes. Additionnally, we showed that endothelial cell activation is mediated by the lectin-like domain of the trans-sialidase rather than the catalytic site, and involves sialylated receptors of the endothelial cell surface. In conclusion, our study brings considerable insights into the host-pathogen relationship and designates sialidases as a central virulence factor in the molecular crosstalk during trypanosomiasis, which makes it a perfect target for the anti-disease strategy

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Mubanga, Joseph. "Animal trypanosomiasis in the Eastern Province of Zambia : epidemiology in the recently-settled areas and evaluation of a novel method for control." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/25002.

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Factors affecting the epidemiology and impact of trypanosomiasis in livestock were studied in households in Mambwe District in an area extending from the Luangwa river valley to the edge of the eastern plateau. A structured questionnaire survey on demography, migration and farm activities of householders showed that about 84% of the households depended on farming for their income, mainly cotton growing. A cross-sectional study of 649 cattle, 811 goats, 58 sheep and 177 pigs in these households used Giemsa-stained blood smears and ITS-PCR amplification for diagnosis of trypanosomiasis. Prevalence was highest in cattle (28.4% [95% CI: 23.7-33.5]) followed by pigs (21.5% [13.9-31.8]), sheep (18.2% [5.1-47.7]), and goats (9.2% [6.8-12.4]). The prevalence within households depended on the particular combinations of livestock species kept; small ruminants were more likely to be infected if cattle were also present. In cattle, prevalence ranged from 26.3% (CI: 19.6-34.2) above 700m above sea level to 44.1% (CI: 36.9-51.6) below 600m. Trypanosoma congolense (savannah type)) was identified in 82.4% of all trypanosome-infected cattle, T. vivax in 24.5%, T. brucei in 2.7%. Trypanosoma simiae was only identified in pigs (27.8% of infected pigs). Finally, ‘restricted application’, a novel modality of use of synthetic pyrethroid to control both tsetse- and tick-borne diseases of cattle was investigated in a longitudinal intervention study in 12 villages in Petauke District on the eastern plateau. Baseline data showed that trypanosomiasis was more prevalent in villages in the northern part of the study are while theileriosis was more prevalent in southern villages. Existing infection of trypanosomes were treated with two doses of diminazene aceturate 42 and 14 days prior to interventions. Spraying only the limbs, belly (predilection feeding sites of tsetse) and ears (predilection feeding site of Rhipicephalus species ticks) of cattle with dilute deltamethrin, was compared with conventional pour-on application of deltamethrin, trypanocidal chemoprophylaxis using isometamidium chloride, and non-intervention controls. Each intervention (or non-intervention) was applied to 80cattle in each of 3 villages, monthly (deltamethrin) or just once (isometamidium). The subsequent incidence of trypanosome infection was too low to make a meaningful conclusion on the interventions. Nevertheless, restricted application had significant effect on tick infestations and animals treated with deltamethrin showed lower cumulative incidence of Theileria species.

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Zhang, Zhengqing. "La trypanosomose animale à Trypanosoma evansi : caractérisation biochimique et génétique de souches provenant de Chine et étude du mécanisme de la chimiorésistance." Lyon 1, 1993. http://www.theses.fr/1993LYO1T202.

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Bouteille, Bernard. "La trypanosomose africaine : des modèles expérimentaux à la physiopathologie et à l'approche thérapeutique de la maladie du sommeil." Lyon 1, 2003. http://www.theses.fr/2003LYO1T158.

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La 4e de couverture indique : "La trypanosomose humaine africaine ou maladie du sommeil évolue en deux phases, une lymphatico-sanguine, puis une neurologique, mortelle en l'absence de traitement. Le diagnostic du stade neurologique est difficile, et son traitement toxique. Nous avons développé plusieurs modèles expérimentaux (souris, mouton, primate non humain) pour permettre son étude, très négligée, alors qu'elle est actuellement en ré-émergence. Nous avons montré l'implication du monoxyde d'azote, du tumor necrosis factor-alpha et d'auto-anticorps dirigés contre des constituants du système nerveux central dans la physiopathologie de la maladie. Ces auto-anticorps présentent un intérêt dans le diagnostic du stade neurologique de la maladie. Parmi les produits trypanocides testés, un dérivé nitro-imidazolé, le mégazol, s'est révélé actif par voie orale au stade neurologique et mériterait un développement. "

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Boulangé, Alain-François. "Clonage et expression des gènes codant pour une HSP70/BIP et une cystéineprotéase de trypanosoma congolense : utilisation de ces antigènes dans l'étude de la trypanotolérance bovine." Bordeaux 2, 1995. http://www.theses.fr/1995BOR28361.

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Tayou, Kamgue Roger Antoine. "Mise au point de nouvelles techniques de dosage de l'isométamidium (Trypamidium®, Samorin®) et ses métabolites dans les milieux biologiques : application pharmacocinétique chez le bovin." Lyon 1, 1989. http://www.theses.fr/1989LYO1T181.

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Soudan, Benoît. "Exploration des anomalies de l'axe hypothalmo-hypophyso-gonadique au cours de la trypanosomiase africaine chez le rat." Lille 1, 1993. http://www.theses.fr/1993LIL10068.

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La trypanosomiase africaine est une affection parasitaire provoquée par un protozoaire flagelle sanguicole, le trypanosome, qui induit des troubles de la reproduction. Notre travail a consisté à déterminer l'origine des anomalies de l'axe gonadotrope provoquées expérimentalement chez le rat mâle par l'inoculation de différents variants de trypanosoma brucei brucei, qui induisent un hypogonadisme révèlé par une chute du taux sérique de testostérone. Les troubles de la reproduction apparaissent multifactoriels : - le stress induit par le parasite et les atteintes inflammatoires secondaires à l'envahissement des tissus par le trypanosome, sont en partie responsables des troubles observés ; - la libération de composés parasitaires de nature non enzymatique pourraient intervenir dans la survenue précoce au cours de l'infestation d'anomalies qualitatives et quantitatives des récepteurs testiculaires de la lh (luteinizing hormone) ; - enfin, la dégradation de neuropeptides comme le lhrh (luteinizing hormone releasing hormone) avec la génération de peptides originaux comme le lhrh#1##4 par des enzymes libèrés par le trypanosome dans la circulation de l'hôte, est un élément également susceptible d'intervenir dans le dysfonctionnement de l'axe hypothalamo-hypophyso-gonadique survenant au cours de la trypanosomiase africaine

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Bodin, Aurélie Lazzari Claudio. "Modulation du comportement de recherche de l'hôte chez les insectes hématophages Importance des facteurs endogènes. /." S. l. : S. n, 2008. http://theses.abes.fr/2008TOUR4019.

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Madrid, Darling Mélany de Carvalho. "Avaliação da ultraestrutura e ação de desinfetantes em Trypanosoma vivax (Ziemann, 1905)." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7693.

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Trypanosoma vivax (Ziemann, 1905) is a protozoon responsible for causing trypanosomiasis in bovines, a disease currently increasing in Brazil and, in the state of Goiás, it was first identified in 2015. As it causes abortion, lethality and greatly diminishes milk production, trypanosomiasis may cause significant losses to farmers, especially those working with milk production. However, there is not much information about this protozoon in Brazil. As it is necessary to gather more knowledge about isolates in the country to evaluate the disease real prevalence, impact in economy and, more importantly, develop control programs, this work proposed evaluate the morphometry of this parasite in scanning electron microscopy and the efficacy of different disinfectants in its elimination. Scanning electron microscopy is a highresolution technique used to analyze the external structures of the parasite, which shows morphometric differences between Latin America and Brazilian isolates. In this work, it was shown that there is no size difference among isolates found in Brazil and Goiás. The results of disinfectants efficacy evaluation to eliminate this agent have shown that many disinfectants commonly found in the market may be used. This information may be applied directly in farms to help control infection focus and contribute in reducing the disease impact in Brazilian milk production.
Trypanosoma vivax (Ziemann, 1905) é o protozoário responsável por causar a tripanossomíase em bovinos, doença que atualmente expressa caráter epidêmico no Brasil e, no estado de Goiás, foi identificada pela primeira vez em 2015. Por ocasionar aborto, letalidade e grande queda de produção de leite, a tripanossomíase pode gerar grandes prejuízos ao produtor, principalmente os que trabalham com bovinocultura de leite. Apesar disto, ainda não há muitas informações disponíveis sobre este protozoário no Brasil. Considerando a necessidade de conhecer mais as características dos isolados presentes no país a fim de avaliar sua prevalência real, impacto na economia e, principalmente, desenvolvimento de programas de controle, este trabalho se propôs avaliar a morfometria do parasito em microscopia eletrônica de varredura e a eficácia de diferentes desinfetantes na sua eliminação. A microscopia eletrônica de varredura é uma técnica de alta resolução empregada para analisar a estrutura externa do parasito, que apresenta diferenças morfométricas entre os isolados na América Latina e no Brasil. Neste trabalho, ficou evidenciado que não há diferença de tamanho entre os isolados encontrados no Brasil e em Goiás. Os resultados da avaliação da eficácia dos desinfetantes em eliminar o agente demonstram que diversos desinfetantes comumente encontrados no mercado podem ser empregados. Estas informações podem ser aplicadas diretamente em propriedades para auxiliar no controle de surtos e contribuir na redução dos impactos causados nos rebanhos bovinos de leite brasileiros.

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Keita, Mahamane. "Etudes histologiques et immunohistologiques de l'evolution de la pathologie du systeme nerveux central au cours de la trypanosomose humaine africaine : utilisation d'un modele chronique experimental chez la souris infectee par trypanosoma brucei brucei." Limoges, 1998. http://www.theses.fr/1998LIMO103C.

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Ben, Younes Chennoufi Amena. "Etude immunopathologique des lésions neuromusculaires de la maladie de Chagas expérimentale de la souris." Paris 6, 1986. http://www.theses.fr/1986PA066216.

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Hamidou, Soumana Illiassou. "La Trypanosomose Humaine Africaine (maladie du sommeil) : caractérisation de gènes impliqués dans les interactions symbiontes - glossines - trypanosomes." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20182.

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Les glossines (mouches tsétsé) sont les vecteurs des trypanosomes africains, responsables de la Trypanosomose Humaine Africaine (THA) ou maladie du sommeil en Afrique sub-saharienne. De nouvelles stratégies de lutte contre la THA visent à utiliser les symbiontes de la glossine pour augmenter sa réfraction à l'infection par les trypanosomes. La mise en place de telles approches nécessite une bonne connaissance des bases moléculaires et cellulaires des interactions entre les symbiontes, la glossine et le trypanosome. Les objectifs de cette thèse étaient, i) d'évaluer l'évolution des densités des symbiontes (Wigglesworthia glossinidia et Sodalis glossinidius) au cours du cycle de développement du vecteur et ii) de caractériser les gènes de Sodalis, Glossina palpalis gambiensis et Trypanosome brucei gambiense en interaction et qui s'expriment différentiellement au cours de l'infection. Nous avons pu montrer la présence permanente des deux symbiontes quel que soit le stade de développement de la glossine, ce qui permet leur utilisation dans le cadre du contrôle des vecteurs. Par la suite, des infections expérimentales ont été réalisées sur des glossines d'insectarium. Des glossines de l'espèce G. p. gambiensis ont été gorgées sur des souris infectées par T. b. gambiense. L'analyse des métatranscriptomes des glossines infectées versus réfractaires à l'infection nous ont permis de mettre en évidence les gènes de Sodalis, G. p. gambiensis et T. b. gambiense différentiellement exprimés aux étapes clé de l'infection. Les résultats qui découlent de cette thèse mettent la lumière sur la complexité des interactions Sodalis - G. p. gambiensis - T. b. gambiense et soulignent l'implication des bactériophages du symbionte S. glossinidius dans la réfraction des glossines à l'infection. Mots clés : maladie du sommeil, mouche tsétsé, trypanosome, symbiontes, compétence vectorielle, expression de gènes
Tsetse flies are the vectors of African trypanosomes, the causative agents of human African trypanosomiasis (sleeping sickness)in sub-saharan Africa. New sleeping sickness control strategies plan to use tsetse gut symbionts to increase tsetse flies refractoriness to trypanosomes infection. Such approaches require good knowledge on the molecular and cellular basis of interactions between symbionts, tsetse fly and trypanosome. This thesis aimed to i) assess the evolution of Glossina palpalis gambiensis symbionts (Wigglesworthia glossinidia and Sodalis glossinidius) densities throughout the host fly development cycle and ii) to characterize genes of Sodalis, G. p. gambiensis and Trypanosoma brucei gambiense in interaction, which are differentially expressed during the infection. We showed that both symbionts are present in all tsetse fly development stages, allowing their use in the context of vector control. Subsequently, experimental infections were performed on colonies flies. G. p. gambiensis female flies were fed on T. b. gambiense hosting mice. Transcriptome of infected flies and flies that have cleared trypanosome they ingested were analysed. This allow us identifying genes of Sodalis, G. p. gambiensis and T. b. gambiense differentially expressed at the infection key stages. Our results highlight the complexity of interactions between Sodalis, G. p. gambiensis, T. b. gambiense and underline the involvement of bacteriophages hosted by S. glossinidius in tsetse fly refractoriness to trypanosome infection. Key words: sleeping sickness; tsetse fly; trypanosome; symbionts; vector competence; gene expression

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Ferreira, Leandro Rodrigues. "Reatividade de \"tripanosomatídeos inferiores\": B. culicis, C. deanei, C. fasciculata, C. luciliae, H. samuelpessoai, L. seymouri, P. serpens e W. inconstans com anticorpos de hospedeiros humanos e cães infectados com Leishmania sp. e T. cruzi." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-18102010-092558/.

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Os tripanosomatídeos inferiores, que infectam plantas e insetos, apresentam propriedades bioquímicas e moleculares similares a Leishmania sp. e Trypanosoma cruzi. Similaridades antigênicas entre estes parasitas são conhecidas à muito tempo, mas somente alguns poucos estudos comparativos sobre a imunorreatividade humoral cruzada foram descritos. No presente trabalho nós analisamos a imunorreatividade cruzada de extratos antigênicos totais de oito tripanosomatídeos inferiores por ELISA, com soros de humanos e cães infectados com T. cruzi e Leishmania sp. Segundo as positividades e dados de reatividade média para ELISA os tripanosomatídeos inferiores foram divididos em dois grupos. ELISA-G1 compreendeu 4 parasitas para os quais se obtiveram 100% de positividade e elevadas médias de absorbância, similar aos dados obtidos para L. chagasi para hospedeiros humanos e cães. Nos casos humanos, soros de pacientes chagásicos crônicos apresentaram 100% de positividade somente para o ELISA com T. cruzi, sem diferenças entre os tripanosomatídeos inferiores. Por outro lado amostras de doenças não relacionadas apresentaram baixa reatividade cruzada com os tripanosomatídeos inferiores. Apesar da sua posição taxonômica em várias sessões e sua antiga divergência estes resultados mostraram semelhança antigênica entre os tripanosomatídeos inferiores e os patogênicos, e podem ser uma fonte alternativa de antígenos para a detecção de anticorpos principalmente em casos de leishmaniose visceral.
\"Lower trypanosomatids\", that infect plant and insect, present biochemical and molecular similarities to Leishmania sp. and Trypanosoma cruzi. Antigenic similarities between those parasites are known for a long time, but only few comparative investigations about immune humoral cross-reaction were described. In the current work we analyze the cross-immunoreactivity of crude extract from eight lower trypanosomatids by ELISA, with human and dog host samples infected with T. cruzi and Leishmania sp. ELISA positivity and data of mean title of human or dog visceral leishmaniasis cases, the lower trypanosomatids were divided in two groups. ELISA-G1 comprised by 4 parasites resulted in 100% positivity and high mean of absorbance, similar data to those obtained with L. chagasi, with human or dog hosts. In human cases, Chagas disease chronic cases showed 100% positive only with ELISA performed with T. cruzi, with no differences among lower trypanosomatids. Otherwise samples with other non correlated disease presented low cross-reaction with lower trypanososmatids. In spite of, their taxonomic position in various sections and their old divergence these results showed a strong antigenic similarity between pathogenic and lower trypanosomatids, and could be an alternative source of antigen for the detection of antibodies against host mainly with visceral leishmaniasis cases.

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Truc, Philippe. "Apport de la génétique des populations à la taxonomie de "Trypanosoma brucei" et à l'épidémiologie de la trypanosomiase humaine en Afrique centrale." Montpellier 2, 1991. http://www.theses.fr/1991MON20050.

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Dans le but d'evaluer l'apport de la genetique des populations, d'une part a la taxonomie des trypanosomes de l'espece trypanosoma brucei, et d'autre part a une comprehension de l'epidemiologie de la trypanosomiase humaine africaine (t. H. A. ), une etude isoenzymatique par electrophorese en acetate de cellulose a ete entreprise sur 55 stocks isoles de l'homme et de l'animal au congo, au zaire et au cameroun. Sur les 24 loci etudies, 15 se sont averes variables, et ont permis d'individualiser 23 zymodemes, eux-meme divises en deux groupes: le premier correspondrait a la sous-espece classique trypanosoma brucei gambiense, la seconde, a la sous-espece classique trypanosoma brucei brucei. Confirmant la taxonomie connue, ces resultats sont corrobores par l'analyse du polymorphisme des fragments de restriction de l'adn kinetoplastique. L'analyse statistique montre que la reproduction des trypanosomes etudies est principalement clonale dans l'aire consideree. Les zymodemes sont assimilables a des clones naturels ou a des familles de clones etroitement apparentees, stables dans l'espace et dans le temps. Leur repartition geographique confirme le caractere endemo-epidemique de la t. H. A. En afrique centrale: d'une part, la circulation des trypanosomes asymptomatiques semble conditionner la dissemination de la maladie, et d'autre part, les reservoirs humains et animaux contribuent a la persistance a l'etat endemique des principaux foyers historiques au congo et au zaire, qui auraient une origine ancestrale commune

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Silva, Taciana de Melo Fernandes. "Estudos de parâmetros clínicos e patológicos em ovelhas infectadas por Trypanosoma vivax no início e final da gestação." Universidade Federal Rural do Semi-Árido, 2012. http://bdtd.ufersa.edu.br:80/tede/handle/tede/342.

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This study aimed to investigate the effect of experimental infection with Trypanosoma vivax in ewes at different stages of pregnancy, to determine the pathogenesis of reproductive failure, and confirm transplacental transmission by PCR. A total of 12 pregnant ewes twelve, adults into three groups G1, consisting of three ewes infected in the first third of pregnancy, G2, consisting of three infected ewes in the final third of gestation, and G3, consisting of six non-infected sheep (control group .) Each ewes G1 and G2 were inoculated with trypomastigotes 1.25 x105. Clinical examination, assessment of hematocrit, serum chemistry, determination of plasma progesterone and parasitemia were determined daily. Pathological examinations were conducted of the fetus, placenta, umbilical cord blood and DNA detection of the parasite in the placenta, amniotic fluid, blood and tissues of fetuses. The parasitaemia was high, reaching peaks of 2.7 x106, being persistent throughout the experimental period. The infection was characterized by the ewes mortality and perinatal mortality in the first third; abortion and perinatal mortality in the final third of gestation. The factors possibly related maternal reproductive failures were low body score, hematocrit, serum glucose, total protein, cholesterol and progesterone. The presence of DNA of T. vivax in the blood and tissues of fetuses, placenta and amniotic fluid, confirming transplacental transmission of the parasite. The presence of histological lesions in the fetal organs and placenta suggest the involvement of the parasite in the pathophysiological mechanism of reproductive damage
O presente estudo teve como objetivo investigar o efeito da infecção experimental por Trypanosoma vivax em ovelhas em diferentes fases da gestação, determinar a patogênese das falhas reprodutivas, e confirmar a transmissão transplacentária por PCR. Foram utilizadas 12 doze ovelhas prenhas, adultas em três grupos experimentais G1, formado por três ovelhas infectadas no terço inicial da gestação; G2, composto por três ovelhas infectadas no terço final da gestação; e G3, constituído por seis ovinos não infectados (grupo controle). Cada ovelha do G1 e G2 foi inoculada com 1,25x105 tripomastigotas. Exames clínicos, avaliação do hematócrito, bioquímica sérica, determinação da concentração plasmática de progesterona e parasitemia foram determinados diariamente. Foram realizados exames anatomopatológicos dos fetos, placenta, cordão umbilical e pesquisa de DNA do parasita na placenta, liquido amniótico, sangue e tecidos dos fetos. A parasitemia foi alta, alcançando picos de 2,7x106, sendo persistente durante todo o período experimental. A infecção foi caracterizada por mortalidade das ovelhas e mortalidade perinatal no terço inicial; aborto e mortalidade perinatal no terço final da gestação. Os fatores possivelmente relacionados com as falhas reprodutivas maternas foram baixos escore corporal, hematócrito, níveis séricos de glicose, proteína total, colesterol e progesterona. A presença do DNA do T. vivax no sangue e tecidos de fetos, placenta e liquido amniótico, confirma a transmissão transplacentária do parasita. A presença de lesões histológicas nos órgãos fetais e placenta sugerem a participação do parasita no mecanismo etiopatogênico de danos reprodutivos

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Guerrini, Laure. "Le risque trypanosomien dans le bassin du Mouhoun au Burkina Faso : approches paysagères : Télédétection - Biogéographie des glossines - Spatialisation du risque." Montpellier 3, 2009. http://www.theses.fr/2009MON30013.

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Les trypanosomoses animales africaines (TAA) sont la principale contrainte pathologique à l’élevage dans le bassin du Mouhoun (Burkina Faso), où leurs principaux vecteurs sont Glossina palpalis gambiensis Vanderplank et G. Tachinoides Westwood. Cette étude a pour objectif général d’appréhender les dynamiques paysagères afin de comprendre la distribution des vecteurs de TAA au Burkina Faso. Ainsi, les cordons ripicoles (CR), leur habitat privilégié, sont décrits afin de mieux comprendre comment les écotypes et leurs niveaux de dégradation conditionnent la présence et l’abondance de ces vecteurs. En se fondant sur les superficies d’eau autour du réseau hydrographique une classification automatique des écotypes a été réalisée (81 % de bon classement). Une analyse paysagère des sept unités végétales péri-riveraines a permis de caractériser le niveau de dégradation des CR. Le lien essentiel entre la conservation des formations ripicoles et la densité des vecteurs a ainsi été mis en évidence. Aussi, une deuxième méthode ciblée sur la fragmentation des forêts (unité favorable aux glossines) a été développée. Cette analyse confirme l’importance de l’intégrité écologique de l’habitat des glossines pour leurs densités (corrélation négative entre fragmentation et abondance). L’identification de ces deux paramètres (écotypes et niveaux de dégradation) par télédétection a alors permis une spatialisation sur l’ensemble du Mouhoun des densités apparentes de glossines (DAP) ainsi que du risque trypanosomien à partir d’un indicateur de risque (l’index entomologique d’inoculation). Les niveaux de risque obtenus pour les deux analyses ont été validés à partir de données de prévalence sur les troupeaux. Les résultats révèlent une très bonne corrélation entre les deux. L’étude de l’évolution de la pluviométrie sur les trente dernières décades a montré une descente des isohyètes vers le sud alors que les limites des glossines restent inchangées, ce qui montre que la structure des forêts galeries est bien le paramètre critique de leur distribution, grâce au microclimat qu’elles génèrent. L’étude diachronique, entre 1986 et 2002, de la composition et de la configuration des paysages favorables aux glossines révèle une fragmentation en cours de leur habitat sur les affluents et une réduction de la fragmentation (régénération des forêts) dans les autres sections écologiques. Des études de dispersion et de génétique des populations ont mis en évidence que si la fragmentation est associée à une réduction des flux entre populations de glossines, celles-ci ne sont pas totalement isolées, permettant d’orienter les choix stratégiques d’un programme d’élimination en cours
African Animal Trypanosomoses is a major hindrance to cattle breeding in the Mouhoun River Basin (Burkina Faso), where their major vectors are Glossina palpalis gambiensis Vanderplank and G. Tachinoides Westwood. The main objective of this study is to apprehend the landscape dynamics to understand the distribution of TAA vectors in Burkina Faso. Thus, the riverine forest, their suitable habitat, is described (ecotypes and disturbance level) and linked to the presence and abundance of vectors. The area of water was used to discriminate automatically three community types of riverine forests (with 81% of overall accuracy). A landscape analysis of the seven peri-riverine vegetation units allowed to characterize the disturbance level of riverine forest. It reveals the essential link between the conservation of their habitat and tsetse densities. A second method focused on the fragmentation of the swampy forests (suitable habitat for tsetse) and confirmed the importance of the ecological integrity of tsetse habitat for their densities (negative correlation between fragmentation and ADT). Using these two parameters (ecotypes and disturbance level), the riverine tsetse fly apparent densities (ADT) and the trypanosomosis risk based on a risk indicator (entomological inoculation rate) were assessed for the entire Mouhoun river. Predicted risk for the both analysis were validated using prevalence data on cattle and reveal a very good correlation. The study of the evolution of pluviometry over the last twenty years showed that although isohyets progressed towards the south, the limits of tsetse distributions remained unchanged, confirming that the structure of gallery forest is the critical parameter of their distribution, thanks to the microclimate that they generate. The diachronic study (between 1986 up to 2002) of the composition and configuration of the suitable habitat for tsetse flies revealed a current fragmentation of their habitat on the tributaries and a reduction of the fragmentation (regeneration of swamp forest) in the others ecological sections. The dispersal and genetic population studies indicate that if the fragmentation is associated to a decrease of the flow of genes between tsetse populations, these populations are not totally isolated. This information is crucial to implement effective elimination strategies

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Bodin, Aurélie. "Modulation du comportement de recherche de l'hôte chez les insectes hématophages : importance des facteurs endogènes." Thesis, Tours, 2008. http://www.theses.fr/2008TOUR4019/document.

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Les animaux ont développé des stratégies d’optimisation de recherche de nourriture afin de minimiser les risques d’exposition aux prédateurs. Chez les insectes hématophages, l’attraction pour leurs hôtes, qui sont également leurs prédateurs, est dirigée par la chaleur et des facteurs chimiques. Cette thèse caractérise les facteurs endogènes modulant le comportement de recherche de l’hôte chez Rhodnius prolixus. Il existe une modulation spécifique de la réponse comportementale à différentes odeurs au cours de la journée. De plus, la recherche de l’hôte est modulée par l’état physiologique des individus (état de développement et état nutritif). Des mécanismes physiologiques et comportementaux ont donc été sélectionnés, inhibant le comportement de recherche de l’hôte à des moments de la vie de l’insecte où il n’est pas nécessaire de s’exposer aux hôtes
Animals have evolved different optimal strategies to minimize predation risks while searching for food. In haematophagous insects, host-seeking is guided by different host stimuli. An important modulation of the perception systems associated to host localization has been observed as function of behaviour and activity rhythms of the host which can be a prey or a predator. We characterize the endogenous factors which could modulate the host-seeking behaviour in the haematophagous bug Rhodnius prolixus. There is a specific modulation of the behavioural response to different odours as function of daytime. Furthermore, host-seeking could be modulated by the physiological state of the bugs (developmental and nutritional state). Physiological and behavioural mechanisms have been selected to inhibit the host-seeking when it is not necessary for the bugs to be exposed to hosts

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D’Amico, Frank. "Rôle de "Glossina fuscipes fuscipes Newstead 1910" dans la transmission des trypanosomes bovines en Afrique centrale : Le cas de la zone d'élevage d'Ouro-Djafoun (République centrafricaine)." Montpellier 2, 1993. http://www.theses.fr/1993MON20214.

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L'élevage bovin en RCA est constitué essentiellement de zébus Mbororo trypanosensibles. Leur activité pastorale, s'articulant autour de trois domaines (aire de repos, abreuvoir et pâturage), les expose à trois espèces de trypanosomes : T. Congolense, T. Vivax et T. Brucei. Au centre du pays, en rapport probable avec le mode de conduite pastorale, les prévalences sont plus faibles chez les veaux que chez les adultes mais sont comparables chez les taureaux et chez les vaches. Glossina fuscipes fuscipes Newstead 1910, espèce inféodée aux galeries forestières et opportuniste sur le plan trophique, héberge au moins cinq espèces de trypanosomes : T. Grayi, T. Simiae, T. Congolense, T. Vivax et T. Brucei. Le taux d'infections matures des trois derniers est de 0,60%. Cette glossine est considérée comme le vecteur principal de ces parasites en les transmettant aux bovins, au niveau des abreuvoirs. Les stomoxes, en particulier Stomoxys Nigra Macquart 1851, seraient des vecteurs accessoires, en assurant une transmission mécanique de ces trypanosomes, au niveau de l'aire de repos du bétail. Le piège bipyramidal, utilisé dans ce travail pour l'échantillonnage des populations de Glossina fuscipes fuscipes, est également un excellent outil de lutte contre cette glossine. Disposé à l'abreuvoir, il en abaisse les densités et rajeunit ses populations. La conséquence directe est une baisse des prévalences trypanosomiennes bovines (6,37% contre 16,63% en l'absence de piégeage)

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Solano, Philippe. "Implications épidémiologiques de la variabilité génétique des populations de glossines. Cas de "Glossina palpalis" en Afrique de l'ouest." Montpellier 2, 1998. http://www.theses.fr/1998MON20169.

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Adam, Yahaya. "Évaluation du risque de Trypanosomose Animale au Ghana, et suivi de l’impact de l’intervention d’éradication de la maladie et du vecteur dans la region Ouest du Ghana." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20210/document.

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Les Trypanosomoses Animales Africaines (TAA) sont une contrainte majeure à la viabilité et à la durabilité des systèmes de production de bétail au Ghana. Sous la tutelle de la Campagne Pan-Africaine d'Eradication des Tsé-tsé et des Trypanosomoses (PATTEC), le Ghana collabore avec le Burkina Faso au sein d'un projet sous régional pour créer une zone libérée de glossines à leur frontière commune. Les objectifs de cette thèse sont de i) déterminer la situation initiale avant intervention en ce qui concerne le vecteur et la prévalence de la maladie dans la zone de lutte, ii) déterminer la structure des populations de glossines et ses conséquences sur la durabilité des efforts de lutte anti-vectorielle, iii) évaluer l'efficacité de la Pulvérisation Séquentielle d'Aérosols insecticides (SAT) pour contrôler les glossines riveraines et iv) évaluer les risques environnementaux associés à cette stratégie de lutte. Les résultats de l'enquête de base conduite dans la région nord-ouest du Ghana (zone d'étude) ont montré une large distribution de Glossina tachinoides alors que Glossina palpalis gambiensis était limitée à la limite sud de la zone d'étude. La prévalence parasitaire moyenne chez les bovins était de 2.5% (IC 95%: 1.06-5.77) et la prévalence sérologique de 19% (IC: 14.03-25.35). La densité apparente par piège et par jour (DAP) des glossines était de 8.7, 1.9 et 1.3 respectivement le long des rivières Volta noire, Kulpawn et Sissili. Une structuration génétique importante des populations de G. tachinoides a été observée entre sites d'étude d'un même bassin versant et entre bassins versants. Une densité locale de 0.48-0.61 glossines/m² a été inférée, ainsi qu'une distance de dispersion d'environ 11m par génération [IC 9 - 17]. Aucun biais de dispersion sexe-spécifique n'a été détecté. La dispersion observée était suffisante pour qu'une zone libérée de G. tachinoides puisse être ré-envahie par les populations mitoyennes des bassins versants adjacents.L'efficacité de la SAT à éliminer les espèces de glossines riveraines dans une section particulièrement difficile (canopée très dense et fortes densités de glossines) et l'efficacité ultérieure, un an après la SAT, d'une stratégie de lutte intégrée, ont également été testées. Les résultats montrent l'échec de l'éradication, attribué à une pénétration insuffisante des aérosols insecticides dans les galeries forestières denses. Toutefois, le taux de réduction global obtenu par la SAT fut important (98%) et la stratégie intégrée parvint à maintenir un niveau important de suppression des glossines. Enfin, une mesure de l'impact environnemental du projet a montré un impact non significatif de la deltaméthrine en aérosols sur les arthropodes aquatiques et terrestres non-ciblés
African animal trypanosomosis (AAT) is a major constraint to viable and sustainable livestock production systems in Ghana. Under the umbrella of the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC), Ghana is collaborating with Burkina Faso in a sub-regional initiative aiming at creating tsetse-free areas across their common borders. The objective of this thesis was to conduct research to guide project implementation and specifically seeks to i) determine the pre-intervention vector and disease situation of the intervention area, ii) determine tsetse population structuring and the consequences on sustainable tsetse control efforts, iii) evaluate SAT for the control of riverine tsetse species in Ghana and iv) evaluate the environmental risk of the intervention programmes. Results of a baseline survey conducted in the Upper West Region (study area) indicated a wide-spread prevalence of Glossina tachinoides but Glossina palpalis gambiensis was limited to the southern edge of the study area. Average parasitological prevalence in cattle was estimated at 2.5% (95% CI: 1.06–5.77) and serological prevalence measured at 19% (95% CI: 14.03–25.35). The mean Index of Apparent Abundance (IAA) of tsetse was 8.7, 1.9 and 1.3 for samples taken along the Black Volta, Kulpawn and Sissili Rivers, respectively. Investigations of the G. tachinoides populations confirmed significant structuring within and between the three main river-basins of the study area, and indicated a local density of 0.48-0.61 flies/m² and dispersal distance that approximated 11 m per generation [CI 9 - 17]. No significant sex-biased dispersal was detected. However, the observed dispersal was deemed sufficient for a G. tachinoides-cleared area to be reinvaded from neighbouring populations in adjacent river basins. The potential of Sequential Aerosol Technique (SAT) to eliminate riverine tsetse species in a challenging subsection (dense tree canopy and high tsetse densities) and the subsequent efficacy of an integrated strategy, one year after the SAT operations, were also investigated. Results indicated failure to achieve elimination, attributed to insufficient penetration of insecticide aerosols in thick riverine forest galleries. However the overall reduction rate due to SAT was important (98%) and the subsequent integrated strategy maintained high levels of tsetse suppression. Finally an environmental impact assessment revealed no significant impact of deltamethrin aerosols on non-targeted aquatic and terrestrial arthropods

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39

Vinauger, Clément. "Apprentissage et mémoire chez les insectes vecteurs de maladies humaines." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4045/document.

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En permettant aux animaux de faire face à des environnements variables, l'apprentissage et la mémoire contribuent à l'optimisation de leur fitness, en leur permettant d'extraire et d'utiliser des informations, de façon à réduire l'incertitude associée à des environnements imprévisibles. Parmi les insectes, la drosophile et l'abeille domestique sont considérés comme des modèles classiques pour l'étude de l'apprentissage et de la mémoire. Les travaux réalisés sur ces derniers ont apporté une quantité considérable d'informations concernant les bases génétiques, neurobiologiques et moléculaires de ces processus, et ont permis de rendre compte du niveau de complexité des capacités cognitives des insectes. Cette somme de connaissances fondamentales acquises chez ces insectes contraste étonnamment avec le faible niveau de connaissance concernant la cognition des espèces impliquées dans des problématiques qui touchent la santé humaine et animale. Pourtant, il est largement admis que l'étude détaillée des capacités cognitives des insectes vecteurs de maladies constitue un aspect prioritaire pour la compréhension de leurs adaptations à la vie hématophage, de leur importance vectorielle, ainsi que pour le développement de nouveaux outils pour leur contrôle. Les travaux réalisés à ce jour chez les vecteurs, principalement chez les moustiques, ont été menés dans des contextes naturels ou peu contrôlés et ne proposent donc pas de démonstration formelle d'apprentissage. Le principal objectif de ce travail de thèse est de proposer un cadre expérimental contrôlé permettant de mettre en évidence et caractériser les capacités d'apprentissage chez la punaise hématophage \textit{Rhodnius prolixus}. \`A la différence des moustiques, les caractéristiques biologiques de cette punaise hématophage, responsable de la transmission de la Maladie de Chagas en Amérique Latine, permettent l'adaptation de protocoles expérimentaux largement validés chez les drosophiles et l'abeille domestique. Nos résultats montrent dans un premier temps que ces insectes sont capables d'apprendre et d'associer la présentation d'une même odeur dite neutre (l'acide lactique), c'est-à-dire qui ne provoque ni attraction ni répulsion lorsqu'elle est présentée seule, avec soit la possibilité d'obtenir une récompense (un repas sanguin, conditionnement appétitif), soit avec la possibilité de recevoir une punition (un choc mécanique, conditionnement aversif). Nous avons également montré que l'apprentissage et la mémoire sont également impliqués dans le choix des hôtes. Les insectes ont en effet associé la présentation d'un choc mécanique avec le complexe d'odeur d'hôtes naturels, biaisant leur préférence lors d'un test de choix réalisé après l'entraînement. Dans un second temps, nous avons adapté à notre modèle d'étude le paradigme de conditionnement de la réponse d'extension du proboscis, développé chez les modèles classiques, ce qui a permis la caractérisation des capacités d'apprentissage, de la durée de rétention à la régulation par des horloges circadiennes. Ces travaux proposent également un paradigme expérimental, reproductible et efficace permettant d'analyser les mécanismes fins qui sous-tendent les processus d'apprentissage et de mémorisation. Dans son ensemble, cette étude apporte la première preuve expérimentale de la capacité d'apprentissage d'insectes vecteurs de la maladie de Chagas et propose des outils expérimentaux et méthodologiques permettant d'améliorer la compréhension des processus associés chez les insectes hématophages en général. Les résultats sont également discutés dans le contexte de la sélection d'hôte et de la transmission des parasites
Learning and memory contribute to animals' fitness by allowing them adapting to variable environments. Thses two processes make them able to extract and use information from their environment in order to reduce the uncertainty associated with unpredictible environments. Among insects, fruit flies and honeybees are considered as classical models for the study of learning and memory. The amount of work that has been done on these models provide a considerable amount of information regarding the genetic, neurobiological and molecular basis of these processes and revealed the complexity of insects' cognitive abilities. All this knowledge acquired in model species, contrasts surprisingly with the lack of knowledge available regarding insect species that are involved in animal and human diseases transmission. Yet, it has been aknowledge that the detailed study of vectors cognitive abilities would allow the understanding of their adaptation to haematophagy, of their vectorial importance and provide new tools for diseases control. Up to date, studies focusing on disaese vectors, mainly in mosquitoes, were conducted in natural or not completely controled contexts and thus no clear demonstration of learning and memory is availaible.The main goal of this work was to provide a controled experimental context allowing the strudy of learning abilities in the haematophagous bug \textit{Rhodnius prolixus}. Our results show that these insectes are able to learn to associate the delivery of a same neutral odour either with the possibility to obtain a reward (blood-meal, appetitive conditioning) or with the possibility to receive a punishment (mechanical shock, aversive conditioning). We also showed that learning ans memory are involved in host selection processes. In a second part, we adapted to our biological model the paradigm of proboscis extension response conditioning, which allowed us to analyse and characterize its learning abilities. The maximal retention duration as well as the modulation of learning abilities by circadian clocks were evinced. Taken as a whole, this work provides the first experimental demonstration of learning abilities in Chagas disease vectors and provides experimental and methodological tools; These latters should allow improving the understanding of the mechanisms that are underlying cearning abilities of haematophagous insects in general. Results are also discussed in the context of host selection and parasite transmission

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40

Vather, Perina. "Vivapain : a cysteine peptidase from Trypanosoma vivax." Thesis, 2010. http://hdl.handle.net/10413/4775.

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African animal trypanosomosis is a devastating disease affecting livestock mainly found in sub-Saharan Africa. This disease is known as nagana and is transmitted by the trypanosome parasite from the tsetse fly vector to a mammalian host. There are three African trypanosomes namely Trypanosoma vivax, T. congolense and T. brucei brucei that are the causative agents responsible for this disease in African cattle. This disease is serious since it not only affects livestock but also has a negative impact on the sub-Saharan African economy. There is, therefore, a great demand for better control methods of the disease and suitable diagnostic methods. Current control measures such as the use of trypanocidal drugs, tsetse fly eradication methods and trypanotolerant cattle have become inadequate. The defence mechanism of the trypanosome to continuously change its surface coat by a process of antigenic variation has made it impossible to produce a suitable vaccine. Therefore, chemotherapy is still one of the key approaches for control of this wasting disease. The long existence of the current trypanocidal drugs has allowed the development of drug resistance. The development of new chemotherapeutic drugs is focused on targeting the pathogenic factors such as parasite cysteine peptidases that contribute to the disease. Vivapain is the main cysteine peptidase of T. vivax and shares high sequence identity with congopain, the main cysteine peptidase of T. congolense, which was previously shown to be a pathogenic factor contributing to trypanosomosis. Vivapain, thus, has potential as a target for chemotherapeutic drug design. Hence, the first part of this study involved the recombinant expression and enzymatic characterisation of vivapain for future production of new synthetic inhibitors for the use in new trypanocidal drugs. The catalytic domain of vivapain (Vp) was recombinantly expressed in the Pichia pastoris yeast expression system and enzymatically characterised. The main finding from this study was that Vp was only able to hydrolyse a substrate if the P2 position was occupied by either a hydrophobic Phe or Leu residue. Vp was also found to be active close to physiological pH and was inhibited by the reversible cysteine peptidases, leupeptin, antipain and chymostatin and the irreversible cysteine peptidases L-trans-epoxysuccinyl-leucylamido (4-guanidino) butane (E-64), iodoacetic acid (IAA) and iodoacetamide (IAN). A further important aspect of controlling trypanosomosis is the diagnosis of the disease. Clinical, parasitological, molecular and serological techniques have been applied and used to diagnose trypanosomosis. One of the most promising serological techniques has proven to be the enzyme-linked immunosorbent assay (ELISA), more specifically the antibody and antigen detection ELISAs. The main requirement for this technique is a readily available and reproducible antigen such as that produced by recombinant expression. While there are recombinant antigens that are available to be used to detect T. congolense, T. brucei brucei and even T. evansi infections, there are none available to detect T. vivax infections. In the second part of this study, a mutant inactive full length form of vivapain (FLVp) was expressed in a bacterial expression system for the detection of T. vivax infections. Antibodies against this antigen were produced in both chickens and mice. Both the chicken IgY and mice sera were able to detect the recombinant FLVp in western blots. The mice sera were also able to detect native vivapain in a T. vivax lysate, which is very promising for future use of the FLVp antigen and the corresponding antibodies in diagnosis of T. vivax infections in sera of infected animals.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

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Bartlett, Cara-Lesley. "Recombinant expression and evaluation of a- and b- tubulin from Trypanosoma congolense as vaccine candidates for African trypanosomiasis." Thesis, 2010. http://hdl.handle.net/10413/4768.

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African trypanosomiasis is caused by protozoan parasites known as trypanosomes, which are transmitted by the tsetse fly, affecting both humans and animals. Trypanosoma congolense is one of the main trypanosome species affecting cattle and causes the disease known as nagana. Control of animal African trypanosomiasis currently relies on chemotherapy and vector control methods, neither of which has proven satisfactory. An effective vaccine against trypanosomiasis would be the most cost effective solution to control the disease; however, due to the phenomenon of antigenic variation, intrinsic to the parasite’s outer coat of variable surface glycoprotein, this has not yet been achieved. Recent vaccine efforts have been centred on identification of invariant parasite antigens for use as vaccine candidates. Trypanosome cytoskeleton components have in recent years been shown to be capable of providing a protective immune response against trypanosome infection. These include tubulin proteins, which form the main components of the cytoskeleton, as well as microtubule associated proteins (MAPs) and paraflagellar rod proteins. In the present study α- and β-tubulin from T. congolense were recombinantly expressed and their immuno-protective potential in mice assessed. Amplification of both α- and β-tubulin ORFs from T. congolense genomic DNA was followed by cloning of the amplicons into the T-vector pTZ57R/T, and thereafter sub-cloning into the bacterial expression vector, pET238a and the yeast expression vector pPICZαA28. Only the α-tubulin amplicon was successfully sub-cloned into pICZAαA28; however, no protein expression was achieved upon transfection of the methylotrophic yeast, Pichia pastoris, with this construct. Subcloning of both α- and β-tubulin inserts into pET28a was successful. Expression of recombinant α- and β-tubulin as fusion proteins with a histidine tag, both at a size of 55 kDa, was achieved in Escherichia coli host BL21 (DE3). Recombinant proteins were successfully purified using nickel chelate chromatography under denaturing conditions. Refolding was first attempted by dilution of purified denatured proteins in a refolding buffer followed by reconcentration, but was largely unsuccessful. A second, more successful refolding method was performed wherein denatured proteins were refolded by application of a decreasing gradient of urea, while bound to a nickel chelate column. Native tubulin from cultured T.congolense procyclics was successfully purified and renatured using a polymerisation/depolymerisation method for use as a control for immunisation. Mice were immunised separately with refolded recombinant α- and β-tubulin, native tubulin or an irrelevant protein VP4AA expressed in the same way as the tubulins. ELISA analysis confirmed the production of antibodies against each protein. Parasitaemia developed in all mice following challenge with T. congolense. Only the group immunised with β-tubulin recorded no deaths during the monitoring period despite the presence of parasitaemia, with 60% of mice immunised with α-tubulin or VP4AA and the no antigen control and no mice from the native tubulin immunised group surviving. The results showed that partial protection against trypanosomiasis caused by T. congolense infection was achieved in the group immunised with β-tubulin and suggest that β-tubulin may have vaccine potential.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

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42

Kangethe, Richard Thiga. "Gene disruption of TcoCATL (Congopain) and oligopeptidase B, pathogenic factors of African trypanosomes." Thesis, 2011. http://hdl.handle.net/10413/8708.

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African trypanosomosis is a parasitic disease in man and animals caused by protozoan parasites of the genus Trypanosoma. T. congolense, T. vivax and T. brucei brucei cause nagana in cattle. The variable nature of the parasite surface coat has hindered the development of an effective vaccine. An option for developing vaccines and chemotherapeutic agents against trypanosomosis is to target pathogenic factors released by the parasite during infection, namely an “anti-disease” approach. Two pathogenic factors released during infection are oligopeptidase B (OPB) and TcoCATL (congopain). TcoCATL, a major lysosomal cysteine peptidase, is a member of the papain family C1 cysteine peptidases. RNA interference (RNAi) was used to down-regulate the expression of TcoCATL in T. congolense IL3000 TRUM183:29-13 parasites in vivo during mouse infections. TcoCATL RNAi was monitored in infected mouse blood by comparing the hydrolysis of Z-Phe-Arg-AMC and parasitaemia between mice in which RNAi was induced and control mice. Mice infected with parasites induced for TcoCATL RNAi had lower parasitaemia when compared to control mice. An attempt was also made at deleting the entire CATL gene array in both T. congolense IL3000 and T. brucei 427 Lister strains. The second pathogenic factor studied, OPB, is a cytosolic trypanosomal peptidase that hydrolyses peptides smaller than 30 amino acid residues, C-terminal to basic residues. In order to evaluate the role that OPB play during disease, RNAi was also applied to knock-down the expression levels of OPB in T. brucei T7T and T. congolense IL3000 TRUM183:29-13 strains (TbOPB and TcoOPB respectively). Oligopeptidase B null mutant strains (Δopb) were also generated in T. brucei brucei Lister 427. An attempt was also made to generate OPB null mutants in T. congolense IL3000 parasites. Western blot analysis of the knock-down experiments using chicken anti-TcoOPB peptide IgY showed that only TbOPB levels were reduced in T. brucei T7T parasites induced for RNAi when compared to TcoOPB RNAi induced cultures. Quantitative assessment of a fourteen day induction experiment for OPB RNAi in T. brucei showed an 87% reduction in TbOPB levels when compared to levels on day one. There was no growth effect observed in T. brucei parasites cultured in vitro and induced for TbOPB RNAi. It was concluded that TbOPB is not necessary for the in vitro survival of T. brucei parasites, thus making the generation of OPB null mutants possible. Δopb T. brucei parasites were successfully generated and grew normally in vitro and were as virulent as wild type strains during infection in mice. Immunohistopatholgy of infected mouse testes revealed Δopb parasites in extra vascular regions showing that T. brucei OPB (TbOPB) is not involved in assisting T. brucei parasites to cross microvascular endothelial cells. Gelatin gel analysis of Δopb null mutants and wild type strains showed an increase in cysteine peptidase activity. Enzymatic activity assays were carried out to identify how closely related oligopeptidases are affected by knocking out TbOPB, and a significant increase of T. brucei prolyl oligopeptidase (TbPOP) activity was observed. However, western blot analysis did not show any increase of TbPOP protein levels in Δopb parasites, suggesting that either TbOPB is responsible for generating an endogenous inhibitor for TbPOP or that another POP-like enzyme might compensate for a loss in OPB activity in Δopb null mutants. This study made a significant contribution to an understanding of the interplay between different trypanosomal peptidases that are important pathogenic factors in trypanosomosis. It highlights the need to simultaneously target several trypanosomal peptidases to develop an effective vaccine or chemotherapeutic agents for African animal trypanosomosis.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

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43

Eyssen, Lauren Elizabeth-Ann. "Studying trypanosomal peptidase antigen targets for the diagnosis of animal African trypanosomiasis." Thesis, 2013. http://hdl.handle.net/10413/11165.

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The lack of a vaccine candidate due to antigenic variation by trypanosomal parasites, the causative agents of human and animal African trypanosomiasis, requires the disease to be controlled by surveillance, diagnosis and appropriate treatment schedules. Due to the non-specific symptoms along with the toxicity and side effects of the current trypanocides, diagnosis needs to be accurate, cost effective and applicable to active case finding in mostly rural settings. Trypanosomal proteases have been identified as virulence factors as they are essential to the parasites‟ survival. Here the diagnostic potential of previously described virulence factors, oligopeptidase B (OPB), pyroglutamyl peptidase (PGP) and the full length and catalytic domain of the cathepsin L-like peptidases (CATLFL and CATL respectively) from T. congolense (Tc) as well as OPB and CATL from T. vivax (Tv), was determined. These antigens were recombinantly expressed, purified and used to generate antibodies in chickens. The purified recombinant antigens were tested in an inhibition and indirect ELISA format using two separate blinded serum panels consisting of sera from non-infected and experimentally infected cattle, one each for T. congolense and for T. vivax. The tested sera were diluted 1:10 for the TcCATLFL, TcCATL antigens whilst the TvCATL antigen used a 1:100 serum dilution. The TcCATLFL, TcCATL and TvCATL antigens had the highest diagnostic potential in the indirect ELISA format with a 90.91, 92.21% accuracy at the second cut-off and a 77.22% accuracy at the third cut-off along with 0.8084, 0.7785 and 0.8813 area under curve (AUC) values respectively. These antigens show potential for development of lateral flow tests to detect T. congolense and T. vivax infections in cattle. The recently discovered metacaspases (MCAs) have been implicated in caspase-like activity and differentiation in T. b. brucei, T. cruzi and L. major and are considered to be virulence factors. The putative metacaspase 5 gene from T. congolense (TcMCA5) was successfully cloned, expressed within inclusion bodies, resolubilised and refolded using immobilised metal affinity chromatography. Recombinant TcMCA5 was successfully refolded as evident by the hydrolysis of the synthetic peptide substrate, Z-Gly-Gly-Arg-AMC. Autocatalytic processing was observed within the inclusion bodies and the products were purified along with the full length recombinant protein. Anti-TcMCA5 IgY antibodies, raised in chickens, were able to detect the native TcMCA5 along with the autocatalytic processed products within the lysate of the procyclic T. congolense (strain IL 3000) parasites. The diagnostic potential of TcMCA5 still requires verification.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

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44

Kalundi, Erastus Mulinge. "Molecular analysis of the congopain gene family." Thesis, 2008. http://hdl.handle.net/10413/4140.

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Animal trypanosomosis is a major constraint in livestock production in Sub-Saharan Africa. With the emergence of resistance against trypanocidal drugs, the cost and environmental concerns raised by vector control, and the challenge of antigenic variation in vaccine development, alternative control measures are being sought. An anti-disease strategy, whereby the immune response or chemotherapy is aimed towards pathogenic factors rather than the parasite itself, constitutes such a novel approach. Congopain is the major cysteine protease in Trypanosoma congolense, and upon release in the bloodstream of infected cattle, acts as a pathogenic factor. It is therefore an attractive candidate for an anti-disease vaccine. It was hence deemed necessary to investigate the variability of congopain-like cysteine proteases before attempting to design drugs and vaccines based on the inhibition of congopain. Most congopain-like cysteine protease genes of T. congolense exist in a single locus of 12-14 copies organised as tandem repeats of 2 kb gene units. A gene unit library of 120 clones was constructed out of several cosmid clones selected in a previous study that contained various lengths of the congopain locus. Some 24 gene unit clones were sequenced, and it was found that congopain genes cluster in three sub-families, named CP1 (8 clones), CP2 (12 clones) and CP3 (4 clones). The latter most characteristically shows a substitution of the active site cysteine by a serine. Isoform specific primers were designed and used to verify the proportions of the three isoforms (one third CP1, half CP2 and a sixth CP3) in the remaining clones of the library. Since this first study was conducted in one isolate, IL 3000, the results were subsequently validated in a large array of isolates, of T. congolense, as well as T. vivax and T. brucei subspecies, by a PCR approach. Finally, to gain access to copies of congopain genes that are not present in the locus, but rather scattered in the genome, an attempt was made to construct a 2 kb size-restricted genomic library. Only 206 clones could be produced, of which a mere 8 coded for congopain-like proteases. The fact that 7 out of 8 of these clones belong to CP3 (thought to be inactive) suggested a cloning artefact, possibly related to the activity of the cloned proteases. Overall, all congopain genes appear very conserved in a given species, with 87-99% identity at protein level. The pre- and pro-region were the most conserved, while the catalytic domain was the most variable, especially around the active site cysteine, with frequent replacement by a serine residue, and in one instance by phenylalanine. The histidine residue of the catalytic triad was also substituted by either a serine or a tyrosine in some instances. The proenzyme cleavage site sequence was also variable, with APEA being the predominant N-terminal sequence. RT-PCR analyses indicated that CP1, CP2 and CP3 mRNA are all present in the bloodstream forms of T. congolense, showing that these variants are likely to be expressed. The conclusion of this study is that, given the high overall conservation of congopain genes in the genome, for the purpose of anti-disease vaccine, it is likely that a single immunogen will suffice to raise antibody able to inhibit all circulating congopain-like cysteine proteases. For chemotherapy however, a more in-depth enzymatic characterisation of the mutants, involving functional recombinant expression, will have to be undertaken.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

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45

Jackson, Laurelle. "Enzymatic and crystallisation studies of CATL-like trypanosomal cysteine peptidases." Thesis, 2011. http://hdl.handle.net/10413/8688.

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African animal trypanosomosis or nagana is a disease in livestock caused by various species of protozoan parasites belonging to the genus Trypanosoma particularly T. congolense, T. vivax and T. b. brucei. Nagana is the most important constraint to livestock and mixed crop-livestock farming in tropical Africa. Trypanosomes undergo part of their developmental life in their insect vector, the tsetse fly and part in their mammalian host. Measures for eradicating the continent of the tsetse fly vector include insecticidal spraying, targeting and trapping. Vaccine development has been hampered by the generation of an inexhaustible collection of variant surface glycoproteins that trypanosomes possess and allow for evasion of the host immune system. Anti-disease vaccines aimed at reducing the symptoms of the disease rather than killing the parasite itself have been demonstrated as an alternative approach. Trypanotolerant cattle are able to protect themselves from the disease-associated symptoms. They are able to mount a better antibody response to the CATL-like cysteine peptidase, TcoCATL, compared to trypanosusceptible breeds. Bovine trypanosomosis, however, continues to be controlled primarily by trypanocidal compounds such as isometamidium chloride, homidium and diaminazene that have been developed more than 50 years ago and consequently drug resistance is widespread. Trypanosomal cysteine peptidases have also been proven to be effective targets for chemotherapeutics. TcrCATL, inhibited by the vinyl sulfone pseudopeptide inhibitor K11777, was effective in curing or alleviating T. cruzi infection in preclinical proof-of-concept studies and has now entered formal preclinical drug development investigation. Understanding enzymatic as well as structural characteristics of pathogenic peptidases is the first step towards successful control of the disease. To date no such characterisation of the major cysteine peptidases from T. vivax has been conducted. Although the major cysteine peptidase from T. vivax, TviCATL, has not been proven as a pathogenic factor yet, its high sequence identity with the pathogenic counterparts such as TcrCATL and TcoCATL hold much speculation for TviCATLs role in pathogenocity. In the present study, native TviCATL was isolated from T. vivax Y486, purified and characterised. TviCATL showed to have a general sensitivity to E-64 and cystatin and has a substrate specificity defined by the S2 pocket. TviCATL exhibited no activity towards the CATB-like substrate, Z-Arg-Arg-AMC but was able to hydrolyse Z-Phe-Arg-AMC, the CATL-like substrate. Leu was preferred in the P2 position and basic and non-bulky hydrophobic residues were accepted in the P1 and P3 positions respectively. Similar findings were reported for TcoCATL. The substrate specificity of TviCATL and TcoCATL does argue for a more restricted specificity compared to TcrCATL. This was based on the Glu333 in TcrCATL substituted with Leu333 in TviCATL and TcoCATL. In the case of TcrCATL, the Glu333 allows for the accommodation of Arg in the P2 position. Like other trypanosomal cysteine peptidases, TviCATL was inhibited by both chloromethyl ketones, Z-Gly-Leu-Phe-CMK and H-D-Val-Phe-Lys-CMK. Determining further structural and functional characteristics as well as whether TviCATL, like the T. congolense homolog, TcoCATL, acts as a pathogenic factor, would be important information to the designing of specific chemotherapeutic agents. To date, TcrCATL and TbrCATL (from T. b. rhodesiense) are the only trypanosomal CATL-like cysteine peptidases been crystallised and their tructures solved. This advantage has allowed for the directed design of synthetic peptidase inhibitors. The crystal structure of TcoCATL will be of major significance to the design of specific chemotherapeutic agents. Furtherrmore, understanding the dimeric conformation of TcoCATL is important for vaccine design as immune responses are likely to recognise the dimer specific epitopes. In the current study, the catalytic domain of TcoCATL and TviCATL, were recombinantly expressed in Pichia pastoris and purified to homogeneity. The T. congolense cysteine peptidase pyroglutamyl peptidase (PGP), also proven to be pathogenic in T. b. brucei, was recombinantly expressed in E. coli BL21 (DE3) cells and also purified to homogeneity. Purified cysteine peptidases along with previously purified TcoCATL dimerisation mutants, TcoCATL (H43W) and TcoCATL (K39F; E44P), possessing mutated residues involved in TcoCATL dimerisation, as well as the mutant proenzyme TcoCATL (C25A), were screened for crystallisation conditions using the Rigaku robotic crystallisation suite. One-dimensional needle-like crystals were found for TcoCATL (K39F; E44P). Optimisation of the TcoCATL (K39F; E44P) crystals were analysed for X-ray diffraction. The poor diffraction pattern prompted further optimisations for better crystal quality, which is presently underway. The crystal structure of TcoCATL, with some of the residues involved in dimerisation mutated, will be pivotal in understanding the dimerisation model. Furthermore, the information about the structure will be valuable for vaccine design and chemotherapeutics development.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

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Mucache, Hermogenes Neves. "Functional expression of Trypanosoma congolense pyroglutamyl peptidase type 1 and development of reverse genetics tools." Thesis, 2012. http://hdl.handle.net/10413/9915.

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Trypanosoma congolense is a protozoan parasite transmitted by tsetse flies. It causes bovine trypanosomosis, the major disease for livestock in sub-Saharan Africa. Control methods include trypanocidal drugs and vector control, but none is fully satisfactory, due to resistance and environmental issues. A method that would have the greatest impact on controlling the disease is vaccination. However, development of a conventional vaccine has been hampered by the mechanism of antigenic variation, which allows the parasite to evade the host’s immune system. An alternative strategy in vaccine design is to target the bioactive compounds released by dead and dying trypanosomes. This approach is termed ‘‘anti-disease’’, and does not affect the survival of the parasite but targets the pathogenic factors released by the trypanosomes. The development of a successful anti-disease vaccine necessitates knowledge of all pathogenic factors involved in the disease process. Several macromolecules, primarily peptidases, have been implicated in the pathogenesis of trypanosomosis. Pyroglutamyl peptidase type I (PGP) was shown to be involved in abnormal degradation of thyrotropin- and gonadotropin-releasing hormones in rodents infected with T. brucei, but to date no data are available on the T. congolense PGP. Molecular cloning and expression in E. coli of the coding sequence of T. congolense PGP, as well as the enzymatic characterisation of the recombinant protein, are reported here, completed by the development of reverse genetics tools for studies of gene function. A 678 bp PCR fragment covering the complete open reading frame of PGP was cloned and sequenced. The deduced amino acid sequence showed 52% and 29% identity with the T. brucei and Leishmania major enzymes respectively. The catalytic residues Glu, Cys and His described in Bacilus amyloliquefaciens PGP are conserved in the T. congolense sequence. PGP was expressed in bacterial systems as a soluble active, 26 kDa enzyme. The recombinant enzyme showed activity specific for the fluorescent substrate pGlu-AMC, with a kcat/Km of 1.11 s-1μM. PGP showed activity in the pH 6.5-10 range, with maximal activity at pH 9.0. The enzyme was strongly inhibited by sulfhydryl-blocking reagents such as iodoacetic acid and iodoacetamide with a kass of 125 M-1 s-1 and 177 M-1 s-1 respectively. Antibodies raised in chickens against the recombinant enzyme allowed the detection of native PGP in both procyclic and bloodstream T. congolense developmental stages, and displayed complete inhibition of the enzyme in vitro at physiological concentrations. To get insight into the role of PGP in parasite biology and trypanosomosis progression, two types of vectors for reverse genetics studies were developed. For RNA interference, a 400 bp 3′ end segment of the PGP open reading frame was cloned into the plasmid p2T7Ti, that will allow PGP gene down-regulation upon integration into the genome of an engineered tetracycline-inducible strain such as TRUM:29-13. For gene knock-out, several rounds of molecular engineering were carried-out in order to create two plasmid vectors, pGL1184-based (blasticidin resistance) and pGL1217-based (neomycin resistance), each bearing 200 bp-long regions at the 5′ and 3′ ends of the PGP open reading frame. In subsequent studies, taking advantage of the recent advances in culture and transformation of T. congolense, these plasmids will allow the creation of single and double knock-out mutants of PGP.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

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Green, Karin Kappmeier. "Strategy for monitoring and sustainable integrated control or eradication of Glossina brevipalpis and G.austeni (Diptera: Glossinidae) in South Africa." Thesis, 2002. http://hdl.handle.net/2263/29893.

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Hamilton, Erika Ann. "Influence of reactive oxygen intermediates in the control of African trypanosomiasis in mice." 2001. https://scholarworks.umass.edu/dissertations/AAI3012134.

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African trypanosomes are parasitic protozoa that cause fatal disease in humans and domestic livestock. Though domestic animals are susceptible to trypanosomiasis, certain wild animals have developed resistance mechanisms. The African cape buffalo can control the early stages of trypanosome infection by increasing plasm and erythrocyte levels of the reactive oxygen intermediate (ROI), hydrogen peroxide (H2O2). Cape buffalo are able to increase the amount of H2O2 produced by the purine catabolic enzyme xanthine oxidase by supplying more substrate in the blood microenvironment and by decreasing the plasma, and erythrocyte levels of catalase, a H2O2 degrading enzyme. My work has been to attempt to manipulate the ROI generating capabilities of mice to recreate this defense mechanism in a small laboratory animal model. Initial experiments revealed that Balb/c, C57Bl/6 and C3H/HeOu mice have all the purine catabolic enzymes necessary to generate trypanocidal amounts of H2O2. However, unlike the buffalo, all of these mouse strains are susceptible to infection by trypanosomes and their serum is not trypanocidal in vitro. Therefore, the ROI generating capabilities of Balb/c, gamma-interferon knockout Balb/c mice and OH catalase-reduced mutant mice were altered by feeding additives, either in a pellet or liquid diet base, to the mice to either inhibit or enhance ROI generation. Only one combination resulted in a slight but significant decrease in parasitemia: C3H catalase-reduced mice fed the catalase inhibitor 3-amino-triazole. Though parasitemia was not effected in any of the other mouse/diet combinations, the mice were effected in some experiments. Gamma-interferon knockout male mice died significantly earlier than female mice, with or without ROI alterations. Mice maintained on a liquid diet had a significantly reduced acceleration of trypanosome-induced inflammation, but this effect was abrogated when the glutathione precursor N-acetyl-cysteine was included in the diet. This indicates that the diets do have an effect on ROI generation in mice, though parasitemia remained largely unaffected. Thus trypanosomes are able to avoid or neutralize ROI in mice. However, they are susceptible to similar ROI levels in buffalo, suggesting a component in the mice that the trypanosomes are able to utilize to inhibit ROI-induced damage.

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Njiru, Basilio Ngari. "The physiological status of the tsetse fly, glossina fuscipes fuscipes, attracted to different hosts and control devices and its implications for control of human and animal african trypanosomiasis." Thesis, 2014. http://hdl.handle.net/10539/15222.

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A dissertation submitted to the faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science. Johannesburg, 2014.
Human African Trypanosomiasis (HAT) is transmitted by Glossina species and remains a serious health problem in Africa. Many aspects of control of the disease have been implemented throughout the years but vector control of tsetse flies has proven to be the most efficient long-term solution. Vector control interventions have been implemented for many tsetse species but relatively little is known about the behaviour of the riverine species, Glossina fuscipes fuscipes. Increased knowledge of this species would improve vector control interventions. This study aimed at: i) understanding the behaviour of tsetse flies around visual devices and odour baits; ii) understanding the behaviour of the flies with regard to human activities; iii) understanding the interaction between the nutritional status of tsetse flies and their attraction to various trapping devices (biconical traps and electric nets); and iv) establishing an age determination curve for field-caught flies. Results showed that visual targets were better attractants then odour-based ones and electric nets performed better than biconical traps. The sticky traps caught 10x more flies (males) than the stationary biconical traps. Sticky traps caught more young flies than the biconical traps which caught more old flies. An age curve was established for flies ranging from 1 day to 60 days old and the fluorescence-based age determination technique, using pteridine levels, has been shown to work for this species. Understanding the behaviour of tsetse flies around trapping devices should lead to improved trapping efficiency. The data gathered will be of importance in assisting with designing and running the Lake Victoria region control operations planned by PATTEC and it will have application in G. f. fuscipes endemic regions in other parts of Africa.

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