Journal articles: 'Trypanosomose africaine'

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Bouteille, Bernard. "Trypanosomose humaine africaine." EMC - Biologie Médicale 1, no. 1 (January 2006): 1–4. http://dx.doi.org/10.1016/s2211-9698(06)76293-8.

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Asonganyi, Tazoacha, S. Suh, and M. D. Tetuh. "Prévalence des trypanosomoses des animaux domestiques dans le foyer de la maladie du sommeil de Fontem au Cameroun." Revue d’élevage et de médecine vétérinaire des pays tropicaux 43, no. 1 (January 1, 1990): 69–74. http://dx.doi.org/10.19182/remvt.8900.

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Les auteurs ont examiné, dans le foyer de la maladie du sommeil de Fontem (Cameroun), 304 animaux domestiques dont 114 chèvres, 93 moutons, 67 chiens et 30 porcs, pour la détection de la trypanosomose, à l'aide des tests parasitologiques et sérologiques. Le sous-genre Nannomonas a été le seul détecté chez les animaux, avec une prévalence de 28,3 p. 100. Le test d'agglutination sur carte (Testryp CATT) a montré un taux de positivité de 38,2 p. 100, ce qui a permis une meilleure estimation de la trypanosomose animale. L'absence des trypanosomes du sous-genre Trypanozoon indique probablement que la trypanosomose humaine africaine n'est pas une zoonose dans ce foyer de la maladie du sommeil.

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Mahama, Charles I., H. A. Mohammed, Martin Abavana, I. Sidibé, A. Koné, and S. Geerts. "Mouches tsé-tsé et trypanosomoses au Ghana au vingtième siècle." Revue d’élevage et de médecine vétérinaire des pays tropicaux 56, no. 1-2 (January 1, 2003): 27. http://dx.doi.org/10.19182/remvt.9871.

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La trypanosomose animale africaine, transmise par les mouches tsé-tsé (Glossina spp.), est un problème majeur limitant l’utilisation optimale de la terre destinée à l’agriculture dans les régions du Ghana infestées de glossines. Au cours des 50 dernières années plusieurs chercheurs ont analysé la distribution des mouches tsé-tsé et la maladie qu’elles transmettent afin d’adapter les mesures de contrôle appropriées. A cause de la croissance démographique et de l’expansion agricole, l’aire de distribution des glossines du groupe morsitans a diminué. Les mouches du groupe palpalis restent les vecteurs les plus importants de la trypanosomose animale, parce qu’elles sont capables de persister même dans les régions fortement occupées par l’agriculture. L’exploitation optimale de la trypanotolérance comme moyen de contrôle des trypanosomoses est entravée par l’utilisation croissante d’animaux croisés avec les races locales trypanosensibles. Bien que l’incidence de la maladie du sommeil ait diminué significativement au cours des dernières décennies, l’état actuel de la maladie n’est pas bien connu. Cette revue décrit l’historique du problème de la trypanosomose et de ses vecteurs au Ghana, examine la situation actuelle de la maladie et identifie quelques priorités de recherche dans l’optique d’un contrôle durable de la trypanosomose.

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Talabani, Hana, and Thierry Ancelle. "Le diagnostic de la trypanosomose humaine africaine." Revue Francophone des Laboratoires 2011, no. 430 (March 2011): 41–46. http://dx.doi.org/10.1016/s1773-035x(11)70824-3.

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Mahamat, Hassane H. "First PATTEC consultative workshop on strategies, technical advances and partnerships in tsetse and trypanosomosis management." Revue d’élevage et de médecine vétérinaire des pays tropicaux 68, no. 1 (November 19, 2015): 45. http://dx.doi.org/10.19182/remvt.20576.

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Les mouches tsé-tsé et les trypanosomoses (T&T) persistent de façon endémique dans de nombreux pays bien que de nombreux efforts aient été consentis ces dernières décennies dans le cadre de l’initiative « Campagne panafricaine d’éradication de la mouche tsé-tsé et de la trypanosomose » (Pattec), et malgré les progrès observés tant au niveau de la recherche et du développement, qu’à celui de l’engagement de nombreux partenaires pour soutenir les efforts de lutte. Dans le but de créer une plateforme multipartite fonctionnelle de lutte contre les T&T, un atelier consultatif réunissant toutes les parties prenantes a été organisé du 8 au 11 septembre 2014. En conclusion de cet atelier, la compétence et la multidisciplinarité des différents partenaires ont été reconnues, mais également la nécessité de progrès dans différents domaines comme la révision des stratégies thérapeutique et chimioprophylactique pour les trypanosomoses animales, l’application de stratégies de surveillance de la trypanosomiase humaine africaine, et la nécessité d’une meilleure compréhension du mécanisme de résistance aux trypanocides et des facteurs permettant le maintien des trypanosomoses non transmises par les tsé-tsé. Le besoin de centraliser les résultats de la recherche opérationnelle afin d’améliorer la formulation des politiques et des techniques de management a également été évoqué. Les systèmes d’information géographique ont été reconnus comme des outils de planification et de gestion de la lutte contre les T&T. Ce premier atelier de concertation s’est terminé par un plaidoyer pour une meilleure communication et une définition claire du rôle de chacun comme gage de réussite d’un partenariat efficace.

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Boka, Ohoukou Marcel, Essehin Enock Jocelin Boka, Grégoire Yapi Yapi, Seïdinan Ibrahima Traoré, and Koffi Eric Kouamé. "Epidémiologie de la trypanosomose animale africaine chez les bovins dans le département du Korhogo (Côte d’Ivoire)." Revue d’élevage et de médecine vétérinaire des pays tropicaux 72, no. 2 (July 10, 2019): 83. http://dx.doi.org/10.19182/remvt.31748.

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Une étude transversale a été menée dans le département du Korhogo, au nord de la Côte d’Ivoire, dans la zone agropastorale de Katégué, afin de mieux connaître l’épidémiologie de la trypanosomose animale africaine (TAA) chez les bovins. L’étude a associé une enquête entomologique et une enquête parasitologique et s’est déroulée en saison des pluies, de juillet à octobre 2015. Les prospections entomologiques ont été réalisées à l’aide de pièges Vavoua posés dans 30 sites aux biotopes divers. Pour l’enquête parasitologique, 407 bovins ont été prélevés sur la base d’un échantillonnage aléatoire stratifié sans distinction de race, de sexe et d’âge. Les résultats ont montré la présence d’un vecteur majeur de la TAA, la mouche tsé-tsé Glossina palpalis gambiensis, avec une densité apparente globale de 0,9 ± 3,0 glossines par piège par jour. Une seule espèce de trypanosome a été identifiée, Trypanosoma vivax, avec des prévalences relativement faibles aussi bien chez les glossines (11 ± 5 %) que chez les bovins (6 ± 2 %). Compte tenu de la gravité de la TAA chez les bovins, il s’avère nécessaire de sensibiliser les éleveurs du Korhogo, qui représente la principale zone d’élevage de bovins en Côte d’Ivoire, à la lutte contre les vecteurs de la TAA et à l’utilisation rationnelle des trypanocides.

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Courtin, F., S. Dupont, D. G. Zeze, V. Jamonneau, B. Sane, B. Coulibaly, G. Cuny, and P. Solano. "Trypanosomose Humaine Africaine: transmission urbaine dans le foyer de Bonon (Cote d'Ivoire)." Tropical Medicine and International Health 10, no. 4 (April 2005): 340–46. http://dx.doi.org/10.1111/j.1365-3156.2005.01398.x.

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Onyeyili, P. A., G. O. Egwu, L. T. Zaria, and B. A. Orjiude. "Activité thérapeutique et prophylactique de la combinaison Berenil^R et DL-alpha-difluorométhylornithine (DFMO^R) contre l’infection à Trypanosoma brucei brucei chez la souris." Revue d’élevage et de médecine vétérinaire des pays tropicaux 44, no. 4 (April 1, 1991): 443–45. http://dx.doi.org/10.19182/remvt.9150.

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Les auteurs ont étudié l'activité théapeutique et prophylactique de l'association DL-alpha-difluorométhylornithine (à la dose de 2 % dans l'eau de boisson) et BerenilR (à 7 mg par kg de poids vif par voie intrapéritonéale) sur des souris infectées par Trypanosoma brucei brucei. Utilisant un modèle sur souris précedemment décrit, de la trypanosomose africaine du système nerveux central, ils ont démontré l'effet curatif de cette association et son action synergétique. Cependant, à titre prophylactique, il n'en résulte aucun avantage par rapport au BerenilR employé seul.

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Kohagne Tongué, L., R. Gounoue Kamkuimo, P. Mengue M’eyi, D. Kaba, F. J. Louis, and R. Mimpfoundi. "Enquête entomologique dans le foyer historique de trypanosomose humaine africaine de Bendjé (Gabon)." Parasite 18, no. 4 (November 2011): 303–9. http://dx.doi.org/10.1051/parasite/2011184303.

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Kohagne Tongué, L., P. Mengue M’Eyi, R. Mimpfoundi, and F. J. Louis. "Régime alimentaire des glossines et diversité des espèces de trypanosomes dans un foyer actif de trypanosomose humaine africaine au Gabon." Bulletin de la Société de pathologie exotique 103, no. 4 (September 6, 2010): 264–71. http://dx.doi.org/10.1007/s13149-010-0062-z.

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Kambiré, R., K. Lingué, F. Courtin, I. Sidibé, D. Kiendrébéogo, K. E. N’gouan, L. blé, et al. "La trypanosomose humaine africaine dans l’espace ivoiro-burkinabé : optimisation des stratégies de surveillance épidémiologique." Parasite 19, no. 4 (November 2012): 389–96. http://dx.doi.org/10.1051/parasite/2012194389.

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Koko, J., S. J. Ategbo, D. Gahouma, E. Engohan-Aloghe, and A. Moussavou. "Trypanosomose humaine africaine révélée par une fièvre prolongée : à propos de trois cas pédiatriques." Archives de Pédiatrie 20, no. 8 (August 2013): 871–73. http://dx.doi.org/10.1016/j.arcped.2013.05.018.

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ANDJINGBOPOU, Y., A. LENGA, R. NZOUMBOU-BOKO, P. BITSINDOU, PM DOUZIMA, and P. MBELESSO. "Situation épidémiologique de la trypanosomose humaine africaine dans la commune de Bilolo en République centrafricaine." Bulletin de la société de pathologie exotique 111, no. 1 (February 28, 2018): 12–16. http://dx.doi.org/10.3166/bspe-2018-0002.

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Roland, Zinga Koumba Christophe, Mbang Nguema Ornella, Midoko Iponga Donald, Mounioko Franck, Mutambwe Shango, Mavoungou Jacques François, and M’batchi Bertrand. "Repartition Des Glossines Dans La Province De L’ogooue Ivindo Ancien Foyer De Trypanosomose Humaine Africaine." European Scientific Journal, ESJ 12, no. 12 (April 28, 2016): 281. http://dx.doi.org/10.19044/esj.2016.v12n12p281.

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In Gabon, the situation of Human African Trypanosomosis (HAT) remains unclear. In addition, several historical foci existing in many provinces have not been explored for over 15 years. Yet many studies have shown that this country has to offer favorable ecosystems for the development of tsetse major vectors of HAT. To verify a risk of transmission of sleeping sickness, a tsetse inventory was conducted in the province of Ogooué Ivindo historic home of HAT. Vavoua and Nzi traps were placed in four characteristic habitats of the province: National Park Ivindo, Zadié Village, Forest of Zadié and baï (clearing) of Momba. A total of 2383 flies were captured: 1680 flies in the clearing of Momba, 437 flies in the primary forest Zadié, 139 in the National Park Ivindo and 12 in Zadié village. Moreover, these flies were divided into 7 species Glossina frezili, Glossina fusca congolensis, Glossina nashi, Glossina palpalis palpalis, Glossina tabaniformis, Glossina fuscipes fuscipes and Glossina tachinoides. Glossina palpalis palpalis (46%) was the most abundant species followed by Glossina fusca congolensis (21%) and Glossina nashi (16%). Glossina fuscipes fuscipes (6%), Glossina frezili (4%), Glossina tabaniformis (4%) and Glossina tachinoides (3%) were the least caught species. These results have shown that the province of Ogooué Ivindo still remains infested by tsetse flies. Also, further study monitoring these insects is essential to clarify the epidemiological importance of these vectors on human health in this province.

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Hope-Rapp, E., O. Moussa Coulibaly, E. Klement, M. Danis, F. Bricaire, and E. Caumes. "Chancres cutanés révélant une trypanosomose africaine à Trypanosoma brucei gambiense chez un résident français au Gabon." Annales de Dermatologie et de Vénéréologie 136, no. 4 (April 2009): 341–45. http://dx.doi.org/10.1016/j.annder.2008.09.023.

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Igbokwe, Ikechukwu Onyebuchi, and Chima Victor Maduka. "Disease burden affecting pig production in Nigeria: Review of current issues and challenges." Revue d’élevage et de médecine vétérinaire des pays tropicaux 71, no. 1-2 (July 3, 2018): 87. http://dx.doi.org/10.19182/remvt.31290.

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L’intérêt croissant pour la production porcine, source complémentaire de protéine animale, se manifeste au Nigeria par une augmentation de la population de porcs. Dans les régions où il n’existe aucune restriction religieuse à la production et à la consommation de porc, la survenue de maladies représente la contrainte majeure à une production profitable de cochons. Les maladies importantes du porc, signalées dans les régions du pays où elles sont présentes, sont recensées dans cette synthèse. La peste porcine africaine, la fièvre aphteuse, la brucellose, la trypanosomose, la babésiose, l’épérythrozoonose, les helminthoses, les coccidioses et les autres parasitoses ont des effets négatifs sur la production (augmentation de l’indice de consommation, réduction du taux de reproduction et de la croissance) aussi bien que sur la mortalité des porcelets et des cochons adultes. Les pertes économiques causées par la charge de morbidité et les stratégies de lutte inadéquates sont des problèmes auxquels est confrontée l’industrie porcine. Les risques de diffusion de zoonoses, comme la grippe, la trypanosomiase, les larva migrans, le ténia, la gale, la cryptosporidiose, la balantidiase, l’ankylostomose, l’amibiase et la tungose (due à Tunga penetrans), à partir de porcs infectés sont réels. Il est essentiel de proposer aux éleveurs des ressources et des services vétérinaires permettant des stratégies de lutte efficaces. Il est également nécessaire de faire une révolution conceptuelle afin de développer la viabilité de la production porcine dans le pays.

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Lelisa, Kumela, and Behablom Meharenet. "Anaemia Associated with Trypanosomes Infections in Cattle of West Gojjam Zone, Northwest Ethiopia." Veterinary Medicine International 2021 (June 29, 2021): 1–7. http://dx.doi.org/10.1155/2021/5531537.

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Background. African animal trypanosomosis is a major veterinary problem over a large area of the tsetse belt region of Africa. Anaemia is a cardinal sign of trypanosome infections. The mechanism of anaemia due to trypanosomosis is complex and multifactorial in origin. Packed cell volume (PCV) usually gives an indication of the anaemia and disease status of a trypanosome-infected animal. Methods. A cross-sectional study was conducted from December 2017 to January 2018 in West Gojjam zone, Northwest Ethiopia, to determine the trypanosome infections rate and the possible correlation between parasitic infection and anaemia using the dark ground buffy coat technique, Giemsa-stained thin blood smear, and PCV reading on a haematocrit reader. Results. The overall trypanosomosis prevalence was 7.81%, 95% CI = 7.45–8.17. Trypanosoma congolense (4.25%) and T. vivax (3.56%) were the trypanosomes species identified in the studied area. PCV for all sampled cattle was analysed to estimate the degree of anaemia. From the total examined animals (N = 730), 356 (48.77%) were anaemic and 374 (51.23%) were nonanaemic. The mean PCV of parasitemic cattle was significantly lower (21.09%, 95% CI = 20.13–22.05) than that of aparasitemic ones (25.96%, 95% CI = 25.68–26.24). There was a positive association between trypanosome infection and anaemia. Although both trypanosome species are significantly associated with a decreased herd mean PCV (<24), the mean PCV of cattle infected with T. congolense (19.45%) was lower than that of infected with T. vivax (23.04%). The herd mean PCV was not significantly associated to locations, age, and sex of the studied animals. Conclusions. The study confirms that the prevalence of trypanosomes infections and herd mean PCV has a significant association. The mean herd PCV can be a useful cheap tool to screen for possible trypanosome infection. However, there were cattle positive for trypanosomes having mean PCV within the reference interval and negative animals with anaemia. Furthermore, PCV reading should be confirmed by other diagnostic techniques to accurately conclude that trypanosomosis is the only cause of anaemia.

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Dibakou, ES, F. Mounioko, CR Zinga Koumba, OA Mbang Nguema, G. Acapovi-Yao, and JF Mavoungou. "Distribution des Glossines vecteurs de la Trypanosomose humaine africaine dans le Parc National de Moukalaba Doudou (Sud-ouest Gabon)." Journal of Applied Biosciences 86, no. 1 (April 14, 2015): 7957. http://dx.doi.org/10.4314/jab.v86i1.7.

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Radwanska, Magdalena, Hang Thi Thu Nguyen, and Stefan Magez. "African Trypanosomosis Obliterates DTPa Vaccine-Induced Functional Memory So That Post-Treatment Bordetella pertussis Challenge Fails to Trigger a Protective Recall Response." Vaccines 9, no. 6 (June 4, 2021): 603. http://dx.doi.org/10.3390/vaccines9060603.

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Salivarian trypanosomes are extracellular parasites causing anthroponotic and zoonotic infections. Anti-parasite vaccination is considered the only sustainable method for global trypanosomosis control. Unfortunately, no single field applicable vaccine solution has been successful so far. The active destruction of the host’s adaptive immune system by trypanosomes is believed to contribute to this problem. Here, we show that Trypanosome brucei brucei infection results in the lasting obliteration of immunological memory, including vaccine-induced memory against non-related pathogens. Using the well-established DTPa vaccine model in combination with a T. b. brucei infection and a diminazene diaceturate anti-parasite treatment scheme, our results demonstrate that while the latter ensured full recovery from the T. b. brucei infection, it failed to restore an efficacious anti-B. pertussis vaccine recall response. The DTPa vaccine failure coincided with a shift in the IgG1/IgG2a anti-B. pertussis antibody ratio in favor of IgG2a, and a striking impact on all of the spleen immune cell populations. Interestingly, an increased plasma IFNγ level in DTPa-vaccinated trypanosome-infected mice coincided with a temporary antibody-independent improvement in early-stage trypanosomosis control. In conclusion, our results are the first to show that trypanosome-inflicted immune damage is not restored by successful anti-parasite treatment.

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Batawui, K., R. De Deken, P. Bastiaensen, A. Napala, and Guy Hendrickx. "Application séquentielle de lambda-cyhalothrine sur le bétail par la méthode Electrodyn^TM. Résultats obtenus au Togo dans le cadre de la lutte contre la trypanosomose animale africaine." Revue d’élevage et de médecine vétérinaire des pays tropicaux 55, no. 3 (March 1, 2002): 189. http://dx.doi.org/10.19182/remvt.9823.

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L’augmentation du prix des produits importés qui a suivi la dévaluation du franc CFA en 1994 a rendu difficile l’accès des éleveurs aux produits de type pour-on, les obligeant à se rabattre sur des méthodes moins fiables pour combattre non seulement les tiques, mais aussi la trypanosomose animale africaine (Taa) transmise par les mouches tsé-tsé ou glossines. En vue de palier à ce problème, le projet de lutte contre la trypanosomose animale au Togo (Plta) a expérimenté une nouvelle méthode d’application couplant les avantages de la méthode pour-on à un coût réduit : ElectrodynTM (Zeneca). Cette méthode est basée sur la pulvérisation électronique d’une formulation insecticide (Karate 2,5 ED®) à base de lambda-cyhalothrine 1 p. 100. L’étude a eu lieu sur 170 bovins dans le village de Skriback au nord du Togo (304 têtes à la fin de l’étude). De mars 1996 à mars 1997, tous les animaux ont été traités et de juillet 1997 à juillet 1998, seulement la moitié d’entre eux. Avant d’entamer la première application du produit, des enquêtes préliminaires ont été menées pendant un an (février 1995 - février 1996) afin d’avoir des données exactes sur la pression des glossines dans la zone et de pouvoir comparer leur densité avant et après le traitement. Les résultats indiquent que ce système a été très efficace dans les conditions de cette étude. L’intervention a permis de réduire la densité des glossines de 99,55 p. 100 et, couplée au traitement trypanocide, de réduire la prévalence de la Taa de 17 à 2 p. 100 ; associée à une vermifugation régulière des animaux, elle a également permis l’amélioration de l’hématocrite moyen du troupeau de 27 à 32,5 p. 100. Du point de vue économique, la méthode Electrodyn revient à un tiers du prix de l’application par la méthode pour-on classique. Elle offre en outre des potentialités considérables en combinaison avec la protection phytosanitaire (coton). La maniabilité de l’applicateur (longueur fixe) et le coût des piles relativement élevé sont les inconvénients qui peuvent entraver l’acceptabilité de la technique.

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Bonnet, J., S. Ducroix-Roubertou, S. Rogez, D. Ajzenberg, B. Courtioux, and J. Faucher. "Faux positifs avec les tests de diagnostic rapide du VIH au cours de la Trypanosomose humaine africaine : étude rétrospective de cohorte." Médecine et Maladies Infectieuses 48, no. 4 (June 2018): S68—S69. http://dx.doi.org/10.1016/j.medmal.2018.04.176.

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Zinga Koumba, Christophe Roland, Franck Mounioko, Aubin Armel Koumba, Julien Zahouli Bi Zahouli, Audrey Pamela Maroundou, Geneviève Acapovi-Yao, Bertrand M’Batchi, and Jacques François Mavoungou. "Évaluation de la composition spécifique des glossines, vectrices de la Trypanosomose Humaine Africaine, dans la région de Ndendé au sud du Gabon." Journal of Applied Biosciences 123, no. 1 (August 29, 2018): 12363. http://dx.doi.org/10.4314/jab.v123i1.5.

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CNOPS, JENNIFER, STEFAN MAGEZ, and CARL De TREZ. "Escape mechanisms of African trypanosomes: why trypanosomosis is keeping us awake." Parasitology 142, no. 3 (December 5, 2014): 417–27. http://dx.doi.org/10.1017/s0031182014001838.

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SUMMARYAfrican trypanosomes have been around for more than 100 million years, and have adapted to survival in a very wide host range. While various indigenous African mammalian host species display a tolerant phenotype towards this parasitic infection, and hence serve as perpetual reservoirs, many commercially important livestock species are highly disease susceptible. When considering humans, they too display a highly sensitive disease progression phenotype for infections withTrypanosoma brucei rhodesienseorTrypanosoma brucei gambiense, while being intrinsically resistant to infections with other trypanosome species. As extracellular trypanosomes proliferate and live freely in the bloodstream and lymphatics, they are constantly exposed to the immune system. Due to co-evolution, this environment however no longer poses a hostile threat, but has become the niche environment where trypanosomes thrive and obligatory await transmission through the bites of tsetse flies or other haematophagic vectors, ideally without causing severe side infection-associated pathology to their host. Hence, African trypanosomes have acquired various mechanisms to manipulate and control the host immune response, evading effective elimination. Despite the extensive research into trypanosomosis over the past 40 years, many aspects of the anti-parasite immune response remain to be solved and no vaccine is currently available. Here we review the recent work on the different escape mechanisms employed by African Trypanosomes to ensure infection chronicity and transmission potential.

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Vanhecke, C., E. Guevart, K. Ezzedine, M. C. Receveur, V. Jamonneau, B. Bucheton, M. Camara, P. Vincendeau, and D. Malvy. "La trypanosomose humaine africaine en faciès épidémiologique de mangrove. Présentation, déterminants et prise en charge dans le contexte de la Guinée (2005 à 2007)." Pathologie Biologie 58, no. 1 (February 2010): 110–16. http://dx.doi.org/10.1016/j.patbio.2009.07.033.

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Yang, Liu, Brian L. Weiss, Adeline E. Williams, Emre Aksoy, Alessandra de Silva Orfano, Jae Hak Son, Yineng Wu, Aurelien Vigneron, Mehmet Karakus, and Serap Aksoy. "Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly’s midgut environment." PLOS Pathogens 17, no. 6 (June 9, 2021): e1009475. http://dx.doi.org/10.1371/journal.ppat.1009475.

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Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse’s ability to transmit trypanosomes by strengthening the fly’s natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse’s PM in order to establish an infection in the fly, and PM structural integrity negatively correlates with trypanosome infection outcomes. Bloodstream form trypanosomes shed variant surface glycoproteins (VSG) into tsetse’s gut lumen early during the infection establishment, and free VSG molecules are internalized by the fly’s PM-producing cardia. This process results in a reduction in the expression of a tsetse microRNA (miR275) and a sequential molecular cascade that compromises PM integrity. miRNAs are small non-coding RNAs that are critical in regulating many physiological processes. In the present study, we investigated the role(s) of tsetse miR275 by developing a paratransgenic expression system that employs tsetse’s facultative bacterial endosymbiont, Sodalis glossinidius, to express tandem antagomir-275 repeats (or miR275 sponges). This system induces a constitutive, 40% reduction in miR275 transcript abundance in the fly’s midgut and results in obstructed blood digestion (gut weights increased by 52%), a significant increase (p-value < 0.0001) in fly survival following infection with an entomopathogenic bacteria, and a 78% increase in trypanosome infection prevalence. RNA sequencing of cardia and midgut tissues from paratransgenic tsetse confirmed that miR275 regulates processes related to the expression of PM-associated proteins and digestive enzymes as well as genes that encode abundant secretory proteins. Our study demonstrates that paratransgenesis can be employed to study microRNA regulated pathways in arthropods that house symbiotic bacteria.

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Makhulu, Edward Edmond, Jandouwe Villinger, Vincent Owino Adunga, Maamun M. Jeneby, Edwin Murungi Kimathi, Enock Mararo, Joseph Wang’ang’a Oundo, Ali Abdulahi Musa, and Lillian Wambua. "Tsetse blood-meal sources, endosymbionts and trypanosome-associations in the Maasai Mara National Reserve, a wildlife-human-livestock interface." PLOS Neglected Tropical Diseases 15, no. 1 (January 6, 2021): e0008267. http://dx.doi.org/10.1371/journal.pntd.0008267.

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African trypanosomiasis (AT) is a neglected disease of both humans and animals caused by Trypanosoma parasites, which are transmitted by obligate hematophagous tsetse flies (Glossina spp.). Knowledge on tsetse fly vertebrate hosts and the influence of tsetse endosymbionts on trypanosome presence, especially in wildlife-human-livestock interfaces, is limited. We identified tsetse species, their blood-meal sources, and correlations between endosymbionts and trypanosome presence in tsetse flies from the trypanosome-endemic Maasai Mara National Reserve (MMNR) in Kenya. Among 1167 tsetse flies (1136 Glossina pallidipes, 31 Glossina swynnertoni) collected from 10 sampling sites, 28 (2.4%) were positive by PCR for trypanosome DNA, most (17/28) being of Trypanosoma vivax species. Blood-meal analyses based on high-resolution melting analysis of vertebrate cytochrome c oxidase 1 and cytochrome b gene PCR products (n = 354) identified humans as the most common vertebrate host (37%), followed by hippopotamus (29.1%), African buffalo (26.3%), elephant (3.39%), and giraffe (0.84%). Flies positive for trypanosome DNA had fed on hippopotamus and buffalo. Tsetse flies were more likely to be positive for trypanosomes if they had the Sodalis glossinidius endosymbiont (P = 0.0002). These findings point to complex interactions of tsetse flies with trypanosomes, endosymbionts, and diverse vertebrate hosts in wildlife ecosystems such as in the MMNR, which should be considered in control programs. These interactions may contribute to the maintenance of tsetse populations and/or persistent circulation of African trypanosomes. Although the African buffalo is a key reservoir of AT, the higher proportion of hippopotamus blood-meals in flies with trypanosome DNA indicates that other wildlife species may be important in AT transmission. No trypanosomes associated with human disease were identified, but the high proportion of human blood-meals identified are indicative of human African trypanosomiasis risk. Our results add to existing data suggesting that Sodalis endosymbionts are associated with increased trypanosome presence in tsetse flies.

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GIBSON, W. C., J. LOM, H. PECKOVÁ, V. R. FERRIS, and P. B. HAMILTON. "Phylogenetic analysis of freshwater fish trypanosomes from Europe using ssu rRNA gene sequences and random amplification of polymorphic DNA." Parasitology 130, no. 4 (December 14, 2004): 405–12. http://dx.doi.org/10.1017/s0031182004006778.

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The taxonomy and phylogenetic relationships of fish trypanosomes are uncertain. A collection of 22 cloned trypanosome isolates from 14 species of European freshwater fish and 1 species of African freshwater fish were examined by molecular phylogenetic analysis. The small subunit ribosomal RNA (ssu rRNA) genes of 8 clones were sequenced and compared with ssu rRNA gene sequences from a wider selection of vertebrate trypanosome isolates by phylogenetic analysis. All trypanosomes from freshwater fish fell in a single clade, subdivided into 3 groups. This clade sits within a larger, robust clade containing trypanosomes from marine fish and various amphibious vertebrates. All 22 trypanosome clones were analysed by random amplification of polymorphic DNA. The resulting dendrogram shows 3 groups, which are congruent with the groups identified in the ssu rRNA gene phylogeny. Two of the groups contain the majority of trypanosome isolates and within-group variation is slight. These groups do not separate purported trypanosome species distinguished by morphology or host origin, and thus these criteria do not appear to be reliable guides to genetic relationships among fish trypanosomes. However, we suggest that the 2 groups themselves may represent different species of fish trypanosomes. The polymorphic DNA markers we have identified will facilitate future comparisons of the biology of these 2 groups of fish trypanosomes.

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GIBSON, W. "Species-specific probes for the identification of the African tsetse-transmitted trypanosomes." Parasitology 136, no. 12 (June 2, 2009): 1501–7. http://dx.doi.org/10.1017/s0031182009006179.

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SUMMARYThe first step in studying the epidemiology of a disease is the accurate identification of the pathogen. Traditional reliance on morphological identification has given way to the use of molecular methods for the detection and identification of pathogens, greatly improving our understanding of epidemiology. For the African tsetse-transmitted trypanosomes, the growth of PCR methods for identification of trypanosomes has led to increased appreciation of trypanosome genetic diversity and discovery of hitherto unknown trypanosome species, as well as greater knowledge about the number and type of trypanosome infections circulating in mammalian hosts and vectors. Sequence data and phylogenetic analysis have provided quantitative information on the relatedness of different trypanosome species and allowed the new trypanosome genotypes discovered through the use of species identification methods in the field to be accurately placed in the phylogenetic tree.

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Liu, M. K., and T. W. Pearson. "Detection of circulating trypanosomal antigens by double antibody ELISA using antibodies to procyclic trypanosomes." Parasitology 95, no. 2 (October 1987): 277–90. http://dx.doi.org/10.1017/s0031182000057735.

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SUMMARYA double antibody sandwich ELISA technique has been developed for detection of antigens of African trypanosomes present in the sera of infected mammals. The assay uses a high titre, high affinity rabbit antiserum made to purified membranes of procyclic trypanosomes as ‘capture’ reagent and a mixture of three biotin-labelled trypanosome-specific monoclonal antibodies as detecting reagent. The monoclonal antibodies were chosen on the basis of their specificity for surface membrane antigens ofTrypanosoma bruceispp., the relative abundance and solubility of their specific antigen in aqueous solvents (including serum), and the fact that each monoclonal antibody binds to distinct epitopes on the same antigen molecule. Thus, antigen capture from serum and subsequent detection was achieved using as little as 10 ng/ml of whole trypanosome lysate, or the equivalent of 5000 trypanosomes/ml when solubilized material was added to normal serum in an artificial system. Using the optimized assay, antigen was detected in the sera of trypanosome-infected mice as early as 2 days after infection withT. b. rhodesiense.The results indicate that the assay allows detection of low concentrations of specific membrane antigens ofT. bruceispp. of African trypanosomes and thus may have immunodiagnostic utility.

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Kanté Tagueu, Sartrien, Oumarou Farikou, Flobert Njiokou, and Gustave Simo. "Prevalence of Sodalis glossinidius and different trypanosome species in Glossina palpalis palpalis caught in the Fontem sleeping sickness focus of the southern Cameroon." Parasite 25 (2018): 44. http://dx.doi.org/10.1051/parasite/2018044.

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Tsetse flies are the cyclical vector of human and animal African trypanosomiasis. To improve vector control in order to achieve the elimination of human African trypanosomiasis (HAT) and boost the control of animal diseases, investigations have been undertaken on the tripartite association between tsetse, trypanosome, and symbionts. It is in this light that Sodalis glossinidius and different trypanosomes were identified in Glossina palpalis palpalis caught in Fontem in southern Cameroon. For this study, DNA was extracted from whole flies, and S. glossinidius and different trypanosome species were identified by polymerase chain reaction (PCR). Statistical analyses were performed to compare the trypanosome and S. glossinidius infection rates and to look for an association between these microorganisms. Of the 274 G. p. palpalis caught, 3.3% (9/274) were teneral. About 35% (96/274) of these flies harbored S. glossinidius. Of the 265 non-teneral flies, 37.7% were infected by trypanosomes. The infection rates of Trypanosoma congolense “forest type” and Trypanosoma vivax were 26.04% and 18.11%, respectively. About 6.41% of tsetse harbored mixed infections of T. congolense and T. vivax. Of the 69 tsetse with T. congolense infections, 33.33% (23/69) harbored S. glossinidius while 71.86% (69/96) of flies harboring S. glossinidius were not infected by trypanosomes. No association was observed between S. glossinidius and trypanosome infections. Some wild tsetse harbor S. glossinidius and trypanosomes, while others have no infection or are infected by only one of these microorganisms. We conclude that the presence of S. glossinidius does not favor trypanosome infections in G. p. palpalis of the Fontem focus.

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Koumba, CRZ, OAM Nguema, LK Tongué, GLA Yao, POO Kutomy, S. Mutambwe, and JF Mavoungou. "Contribution à l’évaluation de la diversité des vecteurs biologiques de la Trypanosomose Humaine Africaine et de leur activité journalière dans le Parc National de l’Ivindo (Nord est Gabon)." Journal of Applied Biosciences 80, no. 1 (September 25, 2014): 7060. http://dx.doi.org/10.4314/jab.v80i1.8.

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Stijlemans, Benoit, Alain Beschin, Stefan Magez, Jo A. Van Ginderachter, and Patrick De Baetselier. "Iron Homeostasis andTrypanosoma bruceiAssociated Immunopathogenicity Development: A Battle/Quest for Iron." BioMed Research International 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/819389.

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African trypanosomosis is a chronic debilitating disease affecting the health and economic well-being of developing countries. The immune response during African trypanosome infection consisting of a strong proinflammatory M1-type activation of the myeloid phagocyte system (MYPS) results in iron deprivation for these extracellular parasites. Yet, the persistence of M1-type MYPS activation causes the development of anemia (anemia of chronic disease, ACD) as a most prominent pathological parameter in the mammalian host, due to enhanced erythrophagocytosis and retention of iron within the MYPS thereby depriving iron for erythropoiesis. In this review we give an overview of how parasites acquire iron from the host and how iron modulation of the host MYPS affects trypanosomosis-associated anemia development. Finally, we also discuss different strategies at the level of both the host and the parasite that can/might be used to modulate iron availability during African trypanosome infections.

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RODRIGUES, A. C., L. NEVES, H. A. GARCIA, L. B. VIOLA, A. MARCILI, F. MAIA DA SILVA, I. SIGAUQUE, J. S. BATISTA, F. PAIVA, and M. M. G. TEIXEIRA. "Phylogenetic analysis of Trypanosoma vivax supports the separation of South American/West African from East African isolates and a new T. vivax-like genotype infecting a nyala antelope from Mozambique." Parasitology 135, no. 11 (August 28, 2008): 1317–28. http://dx.doi.org/10.1017/s0031182008004848.

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SUMMARYIn this study, we addressed the phylogenetic and taxonomic relationships of Trypanosoma vivax and related trypanosomes nested in the subgenus Duttonella through combined morphological and phylogeographical analyses. We previously demonstrated that the clade T. vivax harbours a homogeneous clade comprising West African/South American isolates and the heterogeneous East African isolates. Herein we characterized a trypanosome isolated from a nyala antelope (Tragelaphus angasi) wild-caught in Mozambique (East Africa) and diagnosed as T. vivax-like based on biological, morphological and molecular data. Phylogenetic relationships, phylogeographical patterns and estimates of genetic divergence were based on SSU and ITS rDNA sequences of T. vivax from Brazil and Venezuela (South America), Nigeria (West Africa), and from T. vivax-like trypanosomes from Mozambique, Kenya and Tanzania (East Africa). Despite being well-supported within the T. vivax clade, the nyala trypanosome was highly divergent from all other T. vivax and T. vivax-like trypanosomes, even those from East Africa. Considering its host origin, morphological features, behaviour in experimentally infected goats, phylogenetic placement, and genetic divergence this isolate represents a new genotype of trypanosome closely phylogenetically related to T. vivax. This study corroborated the high complexity and the existence of distinct genotypes yet undescribed within the subgenus Duttonella.

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Rudenko, Gloria. "African trypanosomes: the genome and adaptations for immune evasion." Essays in Biochemistry 51 (October 24, 2011): 47–62. http://dx.doi.org/10.1042/bse0510047.

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The African trypanosome Trypanosoma brucei is a flagellated unicellular parasite transmitted by tsetse flies that causes African sleeping sickness in sub-Saharan Africa. Trypanosomes are highly adapted for life in the hostile environment of the mammalian bloodstream, and have various adaptations to their cell biology that facilitate immune evasion. These include a specialized morphology, with most nutrient uptake occurring in the privileged location of the flagellar pocket. In addition, trypanosomes show extremely high rates of recycling of a protective VSG (variant surface glycoprotein) coat, whereby host antibodies are stripped off of the VSG before it is re-used. VSG recycling therefore functions as a mechanism for cleaning the VSG coat, allowing trypanosomes to survive in low titres of anti-VSG antibodies. Lastly, T. brucei has developed an extremely sophisticated strategy of antigenic variation of its VSG coat allowing it to evade host antibodies. A single trypanosome has more than 1500 VSG genes, most of which are located in extensive silent arrays. Strikingly, most of these silent VSGs are pseudogenes, and we are still in the process of trying to understand how non-intact VSGs are recombined to produce genes encoding functional coats. Only one VSG is expressed at a time from one of approximately 15 telomeric VSG ES (expression site) transcription units. It is becoming increasingly clear that chromatin remodelling must play a critical role in ES control. Hopefully, a better understanding of these unique trypanosome adaptations will eventually allow us to disrupt their ability to multiply in the mammalian bloodstream.

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Robinson, Nicholas P., Nils Burman, Sara E. Melville, and J. David Barry. "Predominance of Duplicative VSG Gene Conversion in Antigenic Variation in African Trypanosomes." Molecular and Cellular Biology 19, no. 9 (September 1, 1999): 5839–46. http://dx.doi.org/10.1128/mcb.19.9.5839.

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ABSTRACT A number of mechanisms have been described by which African trypanosomes undergo the genetic switches that differentially activate their variant surface glycoprotein genes (VSGs) and bring about antigenic variation. These mechanisms have been observed mainly in trypanosome lines adapted, by rapid syringe passaging, to laboratory conditions. Such “monomorphic” lines, which routinely yield only the proliferative bloodstream form and do not develop through their life cycle, have VSG switch rates up to 4 or 5 orders of magnitude lower than those of nonadapted lines. We have proposed that nonadapted, or pleomorphic, trypanosomes normally have an active VSGswitch mechanism, involving gene duplication, that is depressed, or from which a component is absent, in monomorphic lines. We have characterized 88 trypanosome clones from the first two relapse peaks of a single rabbit infection with pleomorphic trypanosomes and shown that they represent 11 different variable antigen types (VATs). The pattern of appearance in the first relapse peak was generally reproducible in three more rabbit infections. Nine of these VATs had activatedVSGs by gene duplication, the tenth possibly also had done so, and only one had activated a VSG by the transcriptional switch mechanism that predominates in monomorphic lines. At least 10 of the donor genes have telomeric silent copies, and many reside on minichromosomes. It appears that trypanosome antigenic variation is dominated by one, relatively highly active, mechanism rather than by the plethora of pathways described before.

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Marsela, Megasari, Kyoko Hayashida, Ryo Nakao, Elisha Chatanga, Alex Kiarie Gaithuma, Kawai Naoko, Janelisa Musaya, Chihiro Sugimoto, and Junya Yamagishi. "Molecular identification of trypanosomes in cattle in Malawi using PCR methods and nanopore sequencing: epidemiological implications for the control of human and animal trypanosomiases." Parasite 27 (2020): 46. http://dx.doi.org/10.1051/parasite/2020043.

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This study aimed to identify trypanosomes infecting cattle in Malawi in order to understand the importance of cattle in the transmission dynamics of Human African Trypanosomiasis (HAT) and Animal African Trypanosomosis (AAT). A total of 446 DNA samples from cattle blood from three regions of Malawi were screened for African trypanosomes by ITS1 PCR. The obtained amplicons were sequenced using a portable next-generation sequencer, MinION, for validation. Comparison of the results from ITS1 PCR and MinION sequencing showed that combining the two methods provided more accurate species identification than ITS1 PCR alone. Further PCR screening targeting the serum resistance-associated (SRA) gene was conducted to detect Trypanosoma brucei rhodesiense. Trypanosoma congolense was the most prevalent Trypanosoma sp., which was found in Nkhotakota (10.8%; 20 of 185), followed by Kasungu (2.5%; 5 of 199). Of note, the prevalence of T. b. rhodesiense detected by SRA PCR was high in Kasungu and Nkhotakota showing 9.5% (19 of 199) and 2.7% (5 of 185), respectively. We report the presence of animal African trypanosomes and T. b. rhodesiense from cattle at the human–livestock–wildlife interface for the first time in Malawi. Our results confirmed that animal trypanosomes are important causes of anemia in cattle and that cattle are potential reservoirs for human African trypanosomiasis in Malawi.

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Gibson, W. C., P. Dukes, and J. K. Gashumba. "Species-specific DNA probes for the identification of African trypanosomes in tsetse flies." Parasitology 97, no. 1 (August 1988): 63–73. http://dx.doi.org/10.1017/s0031182000066749.

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SUMMARYWe have obtained 5 specific DNA probes for African trypanosomes of the subgenera Trypanozoon and Nannomonas. Each probe consists of one repeat unit of the major repetitive DNA (satellite DNA) of each species or intra-specific group. One probe hybridized with all members of subgenus Trypanozoon (except T. equiperdum which was not tested). In subgenus Nannomonas, one probe recognized T. simiae, but 3 probes were needed to identify all stocks of T. congolense available. Each of the 3 latter probes recognized trypanosomes from one of the 3 major groups of T. congolense previously defined by isoenzyme characterization, i.e. savannah, forest and Kenya coast types. As few as 100 trypanosomes could be unequivocally identified by dot blot hybridization and individual trypanosomes could be identified by in situ hybridization. We show how this simple methodology can be used in the field for the identification of immature and mature trypanosome infections in tsetse.

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Abakpa, S. A. V., T. J. Fambegbe, M. I. Takeet, O. O. Daramola, G. O. Akintunde, M. E. Okandeji, and E. O. Okpara. "Prevalence of trypanosomosis and associated haematological changes among hunting dogs in Abeokuta, Nigeria." Nigerian Journal of Animal Production 44, no. 3 (January 2, 2021): 31–37. http://dx.doi.org/10.51791/njap.v44i3.589.

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African animal trypanosomosis (AAT) is one of the major constraints to the development of effective livestock production systems. Dogs are human companion and are believed to be sentinels for infection with the human species. This study was to detect subclinical and clinical infection of trypanosomes among hunting dogs in Abeokuta and its environs using molecular technique. A total of 87 dogs comprising of 49 males and 38 females were ramdomly screened for trypanosomes by polymerase chain reaction technique. Among 87 dogs screened, 17.2% were positive for Trypanosoma congolense and Trypanosoma brucei. Prevalence of trypanosomosis in males was 14.3% while the females accounted for 21.1%.Hematological examination revealed a significant increase (p < 0.05) in mean white blood cells (20.9 ± 2.11) and monocyte counts (5.9 ± 0.62) of the infected dogs compared to uninfected dogs. Packed Cell Volume (36.0 ± 3.73) and haemoglobin concentration (13.9 ± 2.10) decreased insignificantly, while, red blood cells (7.1 ± 0.87), lymphocyte (60.9 ± 9.63), neutrophil (33.3 ± 9.16) and eosinophil (1.4 ± 0.42) counts increased insignificantly (p > 0.05) in infected dogs compared to uninfected dogs. In conclusion, trypanosomosis is prevalent in hunting dogs, in Abeokuta.

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Magez, Stefan, Joar Esteban Pinto Torres, Seoyeon Oh, and Magdalena Radwanska. "Salivarian Trypanosomes Have Adopted Intricate Host-Pathogen Interaction Mechanisms That Ensure Survival in Plain Sight of the Adaptive Immune System." Pathogens 10, no. 6 (May 31, 2021): 679. http://dx.doi.org/10.3390/pathogens10060679.

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Salivarian trypanosomes are extracellular parasites affecting humans, livestock and game animals. Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense are human infective sub-species of T. brucei causing human African trypanosomiasis (HAT—sleeping sickness). The related T. b. brucei parasite lacks the resistance to survive in human serum, and only inflicts animal infections. Animal trypanosomiasis (AT) is not restricted to Africa, but is present on all continents. T. congolense and T. vivax are the most widespread pathogenic trypanosomes in sub-Saharan Africa. Through mechanical transmission, T. vivax has also been introduced into South America. T. evansi is a unique animal trypanosome that is found in vast territories around the world and can cause atypical human trypanosomiasis (aHT). All salivarian trypanosomes are well adapted to survival inside the host’s immune system. This is not a hostile environment for these parasites, but the place where they thrive. Here we provide an overview of the latest insights into the host-parasite interaction and the unique survival strategies that allow trypanosomes to outsmart the immune system. In addition, we review new developments in treatment and diagnosis as well as the issues that have hampered the development of field-applicable anti-trypanosome vaccines for the implementation of sustainable disease control.

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Aksoy, Emre, Aurélien Vigneron, XiaoLi Bing, Xin Zhao, Michelle O’Neill, Yi-neng Wu, James D. Bangs, Brian L. Weiss, and Serap Aksoy. "Mammalian African trypanosome VSG coat enhances tsetse’s vector competence." Proceedings of the National Academy of Sciences 113, no. 25 (May 16, 2016): 6961–66. http://dx.doi.org/10.1073/pnas.1600304113.

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Tsetse flies are biological vectors of African trypanosomes, the protozoan parasites responsible for causing human and animal trypanosomiases across sub-Saharan Africa. Currently, no vaccines are available for disease prevention due to antigenic variation of the Variant Surface Glycoproteins (VSG) that coat parasites while they reside within mammalian hosts. As a result, interference with parasite development in the tsetse vector is being explored to reduce disease transmission. A major bottleneck to infection occurs as parasites attempt to colonize tsetse’s midgut. One critical factor influencing this bottleneck is the fly’s peritrophic matrix (PM), a semipermeable, chitinous barrier that lines the midgut. The mechanisms that enable trypanosomes to cross this barrier are currently unknown. Here, we determined that as parasites enter the tsetse’s gut, VSG molecules released from trypanosomes are internalized by cells of the cardia—the tissue responsible for producing the PM. VSG internalization results in decreased expression of a tsetse microRNA (mir-275) and interferes with the Wnt-signaling pathway and the Iroquois/IRX transcription factor family. This interference reduces the function of the PM barrier and promotes parasite colonization of the gut early in the infection process. Manipulation of the insect midgut homeostasis by the mammalian parasite coat proteins is a novel function and indicates that VSG serves a dual role in trypanosome biology—that of facilitating transmission through its mammalian host and insect vector. We detail critical steps in the course of trypanosome infection establishment that can serve as novel targets to reduce the tsetse’s vector competence and disease transmission.

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PAULNOCK, DONNA M., BAILEY E. FREEMAN, and JOHN M. MANSFIELD. "Modulation of innate immunity by African Trypanosomes." Parasitology 137, no. 14 (November 18, 2010): 2051–63. http://dx.doi.org/10.1017/s0031182010001460.

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SUMMARYThe experimental studies ofBruceigroup trypanosomes presented here demonstrate that the balance of host and parasite factors, especially IFN-γGPI-sVSG respectively, and the timing of cellular exposure to them, dictate the predominant MP and DC activation profiles present at any given time during infection and within specific tissues. The timing of changes in innate immune cell functions following infection consistently support the conclusion that the key events controlling host resistance occur within a short time following initial exposure to the parasite GPI substituents. Once the changes in MP and DC activities are initiated, there appears little that the host can do to reverse these changes and alter the final outcome of these regulatory events. Instead, despite the availability of multiple innate and adaptive immune mechanisms that can control parasites, there is an inability to control trypanosome numbers sufficiently to prevent the emergence and establishment of virulent trypanosomes that eventually kill the host. Overall it appears that trypanosomes have carefully orchestrated the host innate and adaptive immune response so that parasite survival and transmission, and alterations of host immunity, are to its ultimate benefit.

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Nayupe, Symon F. "The use of molecular technology to investigate trypanosome infections in tsetse flies at Liwonde Wild Life Reserve." Malawi Medical Journal 31, no. 4 (December 31, 2020): 233–37. http://dx.doi.org/10.4314/mmj.v31i4.3.

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BackgroundTrypanosomes are protozoan flagellates that cause human African trypanosomiasis (HAT) and African animal trypanosomiasis (AAT). HAT is caused by Trypanosoma brucei rhodesiense in East and Central Africa and T.b. gambiense in West Africa, whereas AAT is caused by a number of trypanosome species, including T. brucei brucei, T. evansi, T. vivax, T. congolense, T. godfreyi and T. simiae. The aim of this study was to establish if tsetse flies at Liwonde Wild Life Reserve (LWLR) are infected with these trypanosomes and thus pose a risk to both humans and animals within and surrounding the LWLR. MethodsA total of 150 tsetse flies were caught. Of these, 82 remained alive after capture and were dissected such that the mid-gut could be examined microscopically for trypanosomes. DNA extractions were performed from both mid-guts and the 68 dead flies using a Qiagen Kit. Amplification techniques involved the Internal Transcriber Spacer 1 (ITS 1) conventional polymerase chain reaction (PCR) with primers designed to identify trypanosome species, and Repetitive Insertion Mobile Element – Loop Mediated Isothermal Amplification (RIME LAMP), a sequence specific to T. brucei.ResultsAnalysis showed that 79/82 (96.3%) of the mid-guts examined microscopically were positive for trypanosomes and that 75/150 (50%) of the DNA extracts (from the mid-gut, and tsetse fly carcasses) were positive for T. brucei, as determined by the RIME LAMP method. ITS1 PCR further showed that 87/150 (58.0%) flies were positive for trypanosomes, of which 56/87 (64.4%) were T. brucei, 9/87 (10.3%) were T. vivax; 7/87 (8.1%) were T. simiae; 6/87 (6.9%) were T. congolense, and 6/87 (6.9%) were T. godfreyi. Ten samples had a mixture of infections. ConclusionOur analysis demonstrated a mixture of infections from trypanosome species in tsetse flies at LWLR, and that T. brucei, the species that causes HAT, was the most common. Our study successfully used molecular techniques to demonstrate the presence of T. b. rhodesiense at LWLR, a species that causes HAT in both East and Central Africa.

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Szöőr, Balázs, Jude Wilson, Helen McElhinney, Lydia Tabernero, and Keith R. Matthews. "Protein tyrosine phosphatase TbPTP1: a molecular switch controlling life cycle differentiation in trypanosomes." Journal of Cell Biology 175, no. 2 (October 16, 2006): 293–303. http://dx.doi.org/10.1083/jcb.200605090.

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Differentiation in African trypanosomes (Trypanosoma brucei) entails passage between a mammalian host, where parasites exist as a proliferative slender form or a G0-arrested stumpy form, and the tsetse fly. Stumpy forms arise at the peak of each parasitaemia and are committed to differentiation to procyclic forms that inhabit the tsetse midgut. We have identified a protein tyrosine phosphatase (TbPTP1) that inhibits trypanosome differentiation. Consistent with a tyrosine phosphatase, recombinant TbPTP1 exhibits the anticipated substrate and inhibitor profile, and its activity is impaired by reversible oxidation. TbPTP1 inactivation in monomorphic bloodstream trypanosomes by RNA interference or pharmacological inhibition triggers spontaneous differentiation to procyclic forms in a subset of committed cells. Consistent with this observation, homogeneous populations of stumpy forms synchronously differentiate to procyclic forms when tyrosine phosphatase activity is inhibited. Our data invoke a new model for trypanosome development in which differentiation to procyclic forms is prevented in the bloodstream by tyrosine dephosphorylation. It may be possible to use PTP1B inhibitors to block trypanosomatid transmission.

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Ibrahim, Mahamat Alhadj Moussa, Judith Sophie Weber, Sen Claudine Henriette Ngomtcho, Djoukzoumka Signaboubo, Petra Berger, Hassane Mahamat Hassane, and Sørge Kelm. "Diversity of trypanosomes in humans and cattle in the HAT foci Mandoul and Maro, Southern Chad—A matter of concern for zoonotic potential?" PLOS Neglected Tropical Diseases 15, no. 6 (June 9, 2021): e0009323. http://dx.doi.org/10.1371/journal.pntd.0009323.

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Background African trypanosomes are parasites mainly transmitted by tsetse flies. They cause trypanosomiasis in humans (HAT) and animals (AAT). In Chad, HAT/AAT are endemic. This study investigates the diversity and distribution of trypanosomes in Mandoul, an isolated area where a tsetse control campaign is ongoing, and Maro, an area bordering the Central African Republic (CAR) where the control had not started. Methods 717 human and 540 cattle blood samples were collected, and 177 tsetse flies were caught. Trypanosomal DNA was detected using PCR targeting internal transcribed spacer 1 (ITS1) and glycosomal glyceraldehyde-3 phosphate dehydrogenase (gGAPDH), followed by amplicon sequencing. Results Trypanosomal DNA was identified in 14 human samples, 227 cattle samples, and in tsetse. Besides T. b. gambiense, T. congolense was detected in human in Maro. In Mandoul, DNA from an unknown Trypanosoma sp.-129-H was detected in a human with a history of a cured HAT infection and persisting symptoms. In cattle and tsetse samples from Maro, T. godfreyi and T. grayi were detected besides the known animal pathogens, in addition to T. theileri (in cattle) and T. simiae (in tsetse). Furthermore, in Maro, evidence for additional unknown trypanosomes was obtained in tsetse. In contrast, in the Mandoul area, only T. theileri, T. simiae, and T. vivax DNA was identified in cattle. Genetic diversity was most prominent in T. vivax and T. theileri. Conclusion Tsetse control activities in Mandoul reduced the tsetse population and thus the pathogenic parasites. Nevertheless, T. theileri, T. vivax, and T. simiae are frequent in cattle suggesting transmission by other insect vectors. In contrast, in Maro, transhumance to/from Central African Republic and no tsetse control may have led to the high diversity and frequency of trypanosomes observed including HAT/AAT pathogenic species. Active HAT infections stress the need to enforce monitoring and control campaigns. Additionally, the diverse trypanosome species in humans and cattle indicate the necessity to investigate the infectivity of the unknown trypanosomes regarding their zoonotic potential. Finally, this study should be widened to other trypanosome hosts to capture the whole diversity of circulating trypanosomes.

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Umaer, Khan, Martin Ciganda, and Noreen Williams. "Ribosome Biogenesis in African Trypanosomes Requires Conserved and Trypanosome-Specific Factors." Eukaryotic Cell 13, no. 6 (April 4, 2014): 727–37. http://dx.doi.org/10.1128/ec.00307-13.

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ABSTRACTLarge ribosomal subunit protein L5 is responsible for the stability and trafficking of 5S rRNA to the site of eukaryotic ribosomal assembly. InTrypanosoma brucei, in addition to L5, trypanosome-specific proteins P34 and P37 also participate in this process. These two essential proteins form a novel preribosomal particle through interactions with both the ribosomal protein L5 and 5S rRNA. We have generated a procyclic L5 RNA interference cell line and found that L5 itself is a protein essential for trypanosome growth, despite the presence of other 5S rRNA binding proteins. Loss of L5 decreases the levels of all large-subunit rRNAs, 25/28S, 5.8S, and 5S rRNAs, but does not alter small-subunit 18S rRNA. Depletion of L5 specifically reduced the levels of the other large ribosomal proteins, L3 and L11, whereas the steady-state levels of the mRNA for these proteins were increased. L5-knockdown cells showed an increase in the 40S ribosomal subunit and a loss of the 60S ribosomal subunits, 80S monosomes, and polysomes. In addition, L5 was involved in the processing and maturation of precursor rRNAs. Analysis of polysomal fractions revealed that unprocessed rRNA intermediates accumulate in the ribosome when L5 is depleted. Although we previously found that the loss of P34 and P37 does not result in a change in the levels of L5, the loss of L5 resulted in an increase of P34 and P37 proteins, suggesting the presence of a compensatory feedback loop. This study demonstrates that ribosomal protein L5 has conserved functions, in addition to nonconserved trypanosome-specific features, which could be targeted for drug intervention.

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VIOLA, L. B., R. S. ALMEIDA, R. C. FERREIRA, M. CAMPANER, C. S. A. TAKATA, A. C. RODRIGUES, F. PAIVA, E. P. CAMARGO, and M. M. G. TEIXEIRA. "Evolutionary history of trypanosomes from South American caiman (Caiman yacare) and African crocodiles inferred by phylogenetic analyses using SSU rDNA and gGAPDH genes." Parasitology 136, no. 1 (November 4, 2008): 55–65. http://dx.doi.org/10.1017/s003118200800512x.

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SUMMARYIn this study, using a combined data set of SSU rDNA and gGAPDH gene sequences, we provide phylogenetic evidence that supports clustering of crocodilian trypanosomes from the Brazilian Caiman yacare (Alligatoridae) and Trypanosoma grayi, a species that circulates between African crocodiles (Crocodilydae) and tsetse flies. In a survey of trypanosomes in Caiman yacare from the Brazilian Pantanal, the prevalence of trypanosome infection was 35% as determined by microhaematocrit and haemoculture, and 9 cultures were obtained. The morphology of trypomastigotes from caiman blood and tissue imprints was compared with those described for other crocodilian trypanosomes. Differences in morphology and growth behaviour of caiman trypanosomes were corroborated by molecular polymorphism that revealed 2 genotypes. Eight isolates were ascribed to genotype Cay01 and 1 to genotype Cay02. Phylogenetic inferences based on concatenated SSU rDNA and gGAPDH sequences showed that caiman isolates are closely related to T. grayi, constituting a well-supported monophyletic assemblage (clade T. grayi). Divergence time estimates based on clade composition, and biogeographical and geological events were used to discuss the relationships between the evolutionary histories of crocodilian trypanosomes and their hosts.

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STEVENS, J. R., H. A. NOYES, G. A. DOVER, and W. C. GIBSON. "The ancient and divergent origins of the human pathogenic trypanosomes, Trypanosoma brucei and T. cruzi." Parasitology 118, no. 1 (January 1999): 107–16. http://dx.doi.org/10.1017/s0031182098003473.

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This study presents new findings concerning the evolution of the human pathogens, Trypanosoma brucei and T. cruzi, which suggest that these parasites have divergent origins and fundamentally different patterns of evolution. Phylogenetic analysis of 18S rRNA sequences places T. brucei in a clade comprising exclusively mammalian trypanosomes of African origin, suggesting an evolutionary history confined to Africa. T. cruzi (from humans and sylvatic mammals) clusters with trypanosomes specific to Old and New World bats, T. rangeli and a trypanosome species isolated from an Australian kangaroo. The origins of parasites within this clade, other than some of those from bats, lie in South America and Australia suggesting an ancient southern super-continent origin for T. cruzi, possibly in marsupials; the only trypanosomes from this clade to have spread to the Old World are those infecting bats, doubtless by virtue of the mobility of their hosts. Viewed in the context of palaeogeographical evidence, the results date the divergence of T. brucei and T. cruzi to the mid-Cretaceous, around 100 million years before present, following the separation of Africa, South America and Euramerica. The inclusion in this study of a broad range of trypanosome species from various different hosts has allowed long phylogenetic branches to be resolved, overcoming the limitations of many previous studies. Moreover, T. brucei and the other mammalian tsetse-transmitted trypanosomes appear, from these data, to be evolving several times faster than T. cruzi and its relatives.

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Nagamune, Kisaburo, Alvaro Acosta-Serrano, Haruki Uemura, Reto Brun, Christina Kunz-Renggli, Yusuke Maeda, Michael A. J. Ferguson, and Taroh Kinoshita. "Surface Sialic Acids Taken from the Host Allow Trypanosome Survival in Tsetse Fly Vectors." Journal of Experimental Medicine 199, no. 10 (May 10, 2004): 1445–50. http://dx.doi.org/10.1084/jem.20030635.

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The African trypanosome Trypanosoma brucei, which causes sleeping sickness in humans and Nagana disease in livestock, is spread via blood-sucking Tsetse flies. In the fly's intestine, the trypanosomes survive digestive and trypanocidal environments, proliferate, and translocate into the salivary gland, where they become infectious to the next mammalian host. Here, we show that for successful survival in Tsetse flies, the trypanosomes use trans-sialidase to transfer sialic acids that they cannot synthesize from host's glycoconjugates to the glycosylphosphatidylinositols (GPIs), which are abundantly expressed on their surface. Trypanosomes lacking sialic acids due to a defective generation of GPI-anchored trans-sialidase could not survive in the intestine, but regained the ability to survive when sialylated by means of soluble trans-sialidase. Thus, surface sialic acids appear to protect the parasites from the digestive and trypanocidal environments in the midgut of Tsetse flies.

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Morty, Rory E., Patrick Bulau, Roger Pellé, Sherwin Wilk, and Koji Abe. "Pyroglutamyl peptidase type I from Trypanosoma brucei: a new virulence factor from African trypanosomes that de-blocks regulatory peptides in the plasma of infected hosts." Biochemical Journal 394, no. 3 (February 24, 2006): 635–45. http://dx.doi.org/10.1042/bj20051593.

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Peptidases of parasitic protozoans are emerging as novel virulence factors and therapeutic targets in parasitic infections. A trypanosome-derived aminopeptidase that exclusively hydrolysed substrates with Glp (pyroglutamic acid) in P1 was purified 9248-fold from the plasma of rats infected with Trypanosoma brucei brucei. The enzyme responsible was cloned from a T. brucei brucei genomic DNA library and identified as type I PGP (pyroglutamyl peptidase), belonging to the C15 family of cysteine peptidases. We showed that PGP is expressed in all life cycle stages of T. brucei brucei and is expressed in four other blood-stream-form African trypanosomes. Trypanosome PGP was optimally active and stable at bloodstream pH, and was insensitive to host plasma cysteine peptidase inhibitors. Native purified and recombinant hyper-expressed trypanosome PGP removed the N-terminal Glp blocking groups from TRH (thyrotrophin-releasing hormone) and GnRH (gonadotropin-releasing hormone) with a kcat/Km value of 0.5 and 0.1 s−1·μM−1 respectively. The half-life of TRH and GnRH was dramatically reduced in the plasma of trypanosome-infected rats, both in vitro and in vivo. Employing an activity-neutralizing anti-trypanosome PGP antibody, and pyroglutamyl diazomethyl ketone, a specific inhibitor of type I PGP, we demonstrated that trypanosome PGP is entirely responsible for the reduced plasma half-life of TRH, and partially responsible for the reduced plasma half-life of GnRH in a rodent model of African trypanosomiasis. The abnormal degradation of TRH and GnRH, and perhaps other neuropeptides N-terminally blocked with a pyroglutamyl moiety, by trypanosome PGP, may contribute to some of the endocrine lesions observed in African trypanosomiasis.

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Caljon, Guy, Jan Van Den Abbeele, Benoît Stijlemans, Marc Coosemans, Patrick De Baetselier, and Stefan Magez. "Tsetse Fly Saliva Accelerates the Onset of Trypanosoma brucei Infection in a Mouse Model Associated with a Reduced Host Inflammatory Response." Infection and Immunity 74, no. 11 (September 5, 2006): 6324–30. http://dx.doi.org/10.1128/iai.01046-06.

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ABSTRACT Tsetse flies (Glossina sp.) are the vectors that transmit African trypanosomes, protozoan parasites that cause human sleeping sickness and veterinary infections in the African continent. These blood-feeding dipteran insects deposit saliva at the feeding site that enables the blood-feeding process. Here we demonstrate that tsetse fly saliva also accelerates the onset of a Trypanosoma brucei infection. This effect was associated with a reduced inflammatory reaction at the site of infection initiation (reflected by a decrease of interleukin-6 [IL-6] and IL-12 mRNA) as well as lower serum concentrations of the trypanocidal cytokine tumor necrosis factor. Variant-specific surface glycoprotein-specific antibody isotypes immunoglobulin M (IgM) and IgG2a, implicated in trypanosome clearance, were not suppressed. We propose that tsetse fly saliva accelerates the onset of trypanosome infection by inhibiting local and systemic inflammatory responses involved in parasite control.

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Journal articles on the topic 'Trypanosomose africaine'

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