To see the other types of publications on this topic, follow the link: Schistosomose.
Journal articles on the topic 'Schistosomose'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Schistosomose.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Diaw, O. T., Georges Vassiliades, Yaya Thiongane, M. Seye, Y. Sarr, and A. Diouf. "Extension des trématodoses du bétail après la construction des barrages dans le bassin du fleuve Sénégal." Revue d’élevage et de médecine vétérinaire des pays tropicaux 51, no. 2 (1998): 113–20. http://dx.doi.org/10.19182/remvt.9635.
Full textAbstract:
Après la mise en service du barrage de Diama (1985-86) et la multiplication des aménagements hydro-agricoles, il a été constaté au niveau du bassin du fleuve Sénégal un développement des trématodoses animales, particulièrement la fasciolose à Fasciola gigantica, les schistosomoses à Schistosoma bovis et à S. curassoni et la paramphistomose à Paramphistomum sp. Cette situation épidémiologique des trématodoses chez le bétail s'est manifestée par une augmentation des prévalences au niveau d'anciens foyers (Richard-Toll, Ross-Béthio, Mbane et Keur Momar Sarr). Les taux d'infestation chez les bovins sont passés de 11 à 27 %, de 20 à 30 % et de 15 à 27 % respectivement pour la fasciolose, la paramphistomose et la schistosomose. Chez les petits ruminants qui semblaient être épargnés, des prévalences de 2 à 62 % pour la fasciolose ont été enregistrées, alors que la paramphistomose, plus fréquente, avait un taux de 25 à 30 %. Parallèlement, à partir de 1989-1990 de nouveaux foyers de trématodoses sont apparus : d'une part, au niveau du delta à Tilène, Pont Gendarme et Takhembeut avec des prévalences de 3 à 20 %, 4 à 20 % et 5 à 36 % respectivement pour fa fasciolose, la schistosomose et la paramphistomose ; d'autre part, au niveau du lac de Guiers à Temeye, Thiago et Senda avec des prévalences de 5 à 86 %, 5 à 11 % et 5 à 33 % respectivement pour la fasciolose, la schistosomose et la paramphistomose.
2
Sampietro, William, Florian Busato, Alain Lecoustumier, Guillaume Normand, Pascal Wuithier, and Antoine Berry. "Schistosomose : en France aussi." La Presse Médicale 47, no. 3 (2018): 291–94. http://dx.doi.org/10.1016/j.lpm.2018.01.002.
Full text
3
Figueiredo, Jacinta, Ângela Santos, Horácio Clemente, et al. "Schistosomose e Apendicite Aguda." Acta Médica Portuguesa 27, no. 3 (2014): 396. http://dx.doi.org/10.20344/amp.5150.
Full textAbstract:
Acute appendicitis associated to Schistosoma haematobium and S. mansoni infection has been found in patients submitted to urgent appendectomy at the Hospital Américo Boavida in Luanda. Due to the high prevalence and morbidity caused by schistosomiasis (or bilharziasis) in the country, we suspect that the involvement of Schistosoma infection on appendicular pathology could be very frequent, in particular for those individuals more exposed to the parasite transmission. We report two clinical cases of acute appendicitis whose surgical specimens of the appendix revealed S. haematobium and S. mansoni eggs in histological samples. The reported patients live in endemic areas and have been exposed to schistosome during childhood, which may explain the infection’s chronicity. Information of these clinical cases could be relevant, particularly for surgery specialists and clinical pathologists, due to the possibility of finding more patients with concurrent appendicitis and schistosomiasis.<br /><strong>Keywords:</strong> Appendicitis/parasitology; Schistosomiasis; Angola; África.
4
Berry, A., X. Iriart, J. Fillaux, and J. F. Magnaval. "Schistosomose urogénitale et cancer." Bulletin de la Société de pathologie exotique 110, no. 1 (2017): 68–75. http://dx.doi.org/10.1007/s13149-017-0547-4.
Full text
5
Grivaux, M., R. Pieron, F. Lancastre, B. Beneteau, and F. C. Baumann. "Enzyme de conversion de l'angiotensine et schistosomose." Médecine et Maladies Infectieuses 16, no. 2 (1986): 72–77. http://dx.doi.org/10.1016/s0399-077x(86)80344-4.
Full text
6
Pieron, R., M. Grivaux, F. Lancastre, A. M. Deluol, and Y. Colin. "Test de dégranulation des basophiles humains et schistosomose." Médecine et Maladies Infectieuses 15, no. 4 (1985): 156–61. http://dx.doi.org/10.1016/s0399-077x(85)80270-5.
Full text
7
Berry, A., J. Fillaux, and X. Iriart. "Schistosomose : une parasitose qui n’est plus uniquement tropicale." Journal des Anti-infectieux 19, no. 3-4 (2017): 119–24. http://dx.doi.org/10.1016/j.antinf.2017.07.001.
Full text
8
Lainé, J. B., O. Grossi, R. Lecomte, et al. "Schistosomose avec atteinte respiratoire : à propos de 3 cas." Médecine et Maladies Infectieuses 48, no. 4 (2018): S107. http://dx.doi.org/10.1016/j.medmal.2018.04.270.
Full text
9
Badawi, A. F., and M. H. Mostafa. "Possible Mechanisms of Alteration in the Capacities of Carcinogen Metabolizing Enzymes during Schistosomiasis and Their Role in Bladder Cancer Induction." Journal of International Medical Research 21, no. 6 (1993): 281–305. http://dx.doi.org/10.1177/030006059302100601.
Full textAbstract:
Carcinoma of the urinary bladder is the most common malignancy in many tropical and subtropical countries. There is a well documented association with chronic urinary schistosomal infection, and bladder cancer associated with schistosomiasis is a major cause of morbidity and mortality in the endemic areas. Many factors have been suggested as possible causative agents in schistosome-associated bladder carcinogenesis but theories concerning the possible role of schistosomal infection in altering host metabolism of chemical carcinogens have received most attention. In experimental schistosomiasis there is a common pattern of changes in the activities of several hepatic Phase I and Phase II enzymes. Phase I enzymes show increased activities in the early stages of infection but these activities are reduced to below their pre-infection levels in the intermediate and late chronic stages of the disease. The activities of Phase II enzymes are altered in favour of the deconjugation pathways in the later stages of the disease. The possible basic mechanisms that might be involved in such changes during parasitism and their potential role in the induction of bladder neoplasia are discussed. Le carcinome de la vessie est la forme de cancer la plus commune dans de nombreux pays tropicaux et sous-tropicaux. Il existe une association bien documentée avec l'infection schistosomale urinaire chronique, et le cancer de la vessie, associé à la schistosomiase, est une cause importante de morbidité et de mortalité dans les régions end miques. De nombreux facteurs ont été suggérés comme agents causatifs possibles dans la carcinogénétique de la vessie associée aux schistosomes mais les théories concernant le rôle possible de l'infection schistosomale dans l'altération du métabolisme de l'hôte de carcinogènes chimiques, ont été beaucoup plus écoutées. Dans le schistosomiase expérimentale, on observe un module commun dans les modifications de activités des plusieurs enzymes hépatiques de phase I et de phase II. Les enzymes de phase I présentent un accroissement d'activités aux stades précoces de l'infection mais ces activités diminuent pour tomber á des niveaux inférieurs á ceux préables á l'infection pendant les stades intermédiaires et chroniques de la maladie. Les activités des enzymes de phase II sont modifiées en faveur de voies de d conjugaison à des stades plus avancés de la maladie. Les mécanimses de base qui sont peut-être impliqués dans ces changements pendant le parasitisme et leur rôle potentiel dans le déclenchement d'une néoplasie de la vessie sont examinés.
10
MANN, V. H., M. E. MORALES, K. J. KINES, and P. J. BRINDLEY. "Transgenesis of schistosomes: approaches employing mobile genetic elements." Parasitology 135, no. 2 (2007): 141–53. http://dx.doi.org/10.1017/s0031182007003824.
Full textAbstract:
SUMMARYDraft genome sequences forSchistosoma mansoniandSchistosoma japonicumare now available. However, the identity and importance of most schistosome genes have yet to be determined. Recently, progress has been made towards the genetic manipulation and transgenesis of schistosomes. Both loss-of-function and gain-of-function approaches appear to be feasible in schistosomes based on findings described in the past 5 years. This review focuses on reports of schistosome transgenesis, specifically those dealing with the transformation of schistosomes with exogenous mobile genetic elements and/or their endogenous relatives for the genetic manipulation of schistosomes. Transgenesis mediated by mobile genetic elements offers a potentially tractable route to introduce foreign genes to schistosomes, a means to determine the importance of schistosome genes, including those that could be targeted in novel interventions and the potential to undertake large-scale forward genetics by insertional mutagenesis.
11
Diaw, O. T., M. Seye, and Y. Sarr. "Épidémiologie des trématodoses du bétail dans la région de Kolda, Casamance (Sénégal)." Revue d’élevage et de médecine vétérinaire des pays tropicaux 41, no. 3 (1988): 257–64. http://dx.doi.org/10.19182/remvt.8689.
Full textAbstract:
Des enquêtes effectuées de 1977 à 1980, puis en 1985 et 1986, ont permis d’étudier l’épidémiologie des trématodoses du bétail dans le département de Kolda : - Détermination de la nature et des taux d’infestation des animaux au niveau des abattoirs de Kolda. Chez les bovins, on enregistre une baisse considérable de la distomatose, alors que la schistosomose progresse sensiblement. Chez les petits ruminants, les taux d’infestation sont très faibles. - Identification des mollusques dans les différents points d’eau et étude de leur rôle dans la transmission des trématodoses. La région de Kolda, de par son climat et sa pluviométrie, offre les conditions idéales au maintien des trématodoses qui risquent de s’étendre avec les aménagements hydroagricoles.
12
Bullington, Brooke W., Katherine Klemperer, Keith Mages, et al. "Effects of schistosomes on host anti-viral immune response and the acquisition, virulence, and prevention of viral infections: A systematic review." PLOS Pathogens 17, no. 5 (2021): e1009555. http://dx.doi.org/10.1371/journal.ppat.1009555.
Full textAbstract:
Although a growing number of studies suggest interactions between Schistosoma parasites and viral infections, the effects of schistosome infections on the host response to viruses have not been evaluated comprehensively. In this systematic review, we investigated how schistosomes impact incidence, virulence, and prevention of viral infections in humans and animals. We also evaluated immune effects of schistosomes in those coinfected with viruses. We screened 4,730 studies and included 103. Schistosomes may increase susceptibility to some viruses, including HIV and Kaposi’s sarcoma-associated herpesvirus, and virulence of hepatitis B and C viruses. In contrast, schistosome infection may be protective in chronic HIV, Human T-cell Lymphotropic Virus-Type 1, and respiratory viruses, though further research is needed. Schistosome infections were consistently reported to impair immune responses to hepatitis B and possibly measles vaccines. Understanding the interplay between schistosomes and viruses has ramifications for anti-viral vaccination strategies and global control of viral infections.
13
De Vathaire, F., J. P. Pointier, J. A. Meyer, and A. J. Valleron. "Modélisation de l’infestation deBiomphalaria GlabrataparSchistosoma mansoni,agent de la schistosomose intestinale en Guadeloupe (Antilles Françaises)." Annales de Parasitologie Humaine et Comparée 64, no. 6 (1989): 443–55. http://dx.doi.org/10.1051/parasite/1989646443.
Full text
14
Agrawal, M. C., and V. G. Rao. "Indian Schistosomes: A Need for Further Investigations." Journal of Parasitology Research 2011 (2011): 1–4. http://dx.doi.org/10.1155/2011/250868.
Full textAbstract:
India is uniquely positioned with regard to schistosomes and schistosomiasis—discovering seven new mammalian species with the existence of three more schistosome species:Orientobilharzia turkestanicum, O. harinasutai, and Schistosoma haematobium(?). An endemic focus of urinary schistosomiasis was reported from Gimvi village of Ratnagiri, Maharashtra with infrequent occurrence of schistosome eggs in human stools. Cercarial dermatitis has been reported to be more abundant in rural population using ponds, tanks, and so forth, for their domestic purposes. Few dermatitis cases were tested positive by CHR. Schistosome antigen was also detected in urine of five cases suggesting existence of active schistosomiasis in India. Nevertheless, human kind does not appear to be the usual host for Indian schistosomes in contrast toS. haematobium, S. mansoni,orS. japonicum. Various reasons for this phenomenon are discussed including evolution of Indian schistosomes, immune mechanisms, and environmental conditions. These and other aspects such as seasonal effect on the prevalence, snail infectivity, heterologous mating, existence of hybrids, and number of schistosomes in heterologous infections need further investigations with application of molecular techniques. Joint efforts by the national as well as international scientific community would be much more rewarding for better understanding of the parasite and the infection.
15
Brant, S. V., and E. S. Loker. "Schistosomes in the southwest United States and their potential for causing cercarial dermatitis or ‘swimmer's itch’." Journal of Helminthology 83, no. 2 (2009): 191–98. http://dx.doi.org/10.1017/s0022149x09308020.
Full textAbstract:
AbstractCercarial dermatitis or swimmer's itch results when cercariae of schistosomes penetrate human skin and initiate inflammatory responses. The parasites typically die in the skin but in some cases may persist and infect other organs. Cercarial dermatitis is caused by a complex and poorly known assemblage of schistosome species, and can occur in any location where people come in contact with water bodies harbouring schistosome-infected snails. In North America, most cases are reported from the upper Midwest. In south-western USA, this phenomenon has not been well studied, and it is not known which schistosome species are present, or if cercarial dermatitis occurs with any regularity. As part of our ongoing studies of schistosome diversity, using morphological traits and sequence data to differentiate species, we have thus far identified eight schistosome genetic lineages from snails from New Mexico and Colorado. We have investigated two cercarial dermatitis outbreaks, one occurring in Stubblefield Lake in northern New Mexico, and one in Prospect Lake in the heart of Colorado Springs, Colorado. The New Mexico outbreak involved either one or two different avian schistosome species, both transmitted by physid snails. The Colorado outbreak was due to Trichobilharzia brantae, a species transmitted by geese and the snail Gyraulus parvus. These outbreaks are in contrast to those in northern states where schistosomes infecting snails of the family Lymnaeidae are more often responsible for outbreaks. Our survey suggests that dermatitis-causing schistosomes are not rare in the southwest, and that there are plenty of opportunities for dermatitis outbreaks to occur in this region.
16
Jothikumar, Narayanan, Bonnie J. Mull, Sara V. Brant, et al. "Real-Time PCR and Sequencing Assays for Rapid Detection and Identification of Avian Schistosomes in Environmental Samples." Applied and Environmental Microbiology 81, no. 12 (2015): 4207–15. http://dx.doi.org/10.1128/aem.00750-15.
Full textAbstract:
ABSTRACTCercarial dermatitis, also known as swimmer's itch, is an allergenic skin reaction followed by intense itching caused by schistosome cercariae penetrating human skin. Cercarial dermatitis outbreaks occur globally and are frequently associated with freshwater lakes and are occasionally associated with marine or estuarine waters where birds reside year-round or where migratory birds reside. In this study, a broadly reactive TaqMan assay targeting 18S rRNA gene (ribosomal DNA [rDNA]) sequences that was based on a genetically diverse panel of schistosome isolates representing 13 genera and 20 species (the 18S rDNA TaqMan assay) was developed. A PCR assay was also developed to amplify a 28S rDNA region for subsequent sequencing to identify schistosomes. When applied to surface water samples seeded withSchistosoma mansonicercariae, the 18S rDNA TaqMan assay enabled detection at a level of 5S. mansonicercariae in 100 liters of lake water. The 18S rDNA TaqMan and 28S rDNA PCR sequencing assays were also applied to 100-liter water samples collected from lakes in Nebraska and Wisconsin where there were reported dermatitis outbreaks. Avian schistosome DNA was detected in 11 of 34 lake water samples using the TaqMan assay. Further 28S rDNA sequence analysis of positive samples confirmed the presence of avian schistosome DNA and provided a preliminary identification of the avian schistosomes in 10 of the 11 samples. These data indicate that the broadly schistosome-reactive TaqMan assay can be effective for rapid screening of large-volume water samples for detection of avian schistosomes, thereby facilitating timely response actions to mitigate or prevent dermatitis outbreaks. Additionally, samples positive by the 18S rDNA TaqMan assay can be further assayed using the 28S rDNA sequencing assay to both confirm the presence of schistosomes and contribute to their identification.
17
Ahmed, Mohamed S., Reda E. Khalafalla, Ashraf Al-Brakati, Tokuma Yanai, and Ehab Kotb Elmahallawy. "Descriptive Pathological Study of Avian Schistosomes Infection in Whooper Swans (Cygnus cygnus) in Japan." Animals 10, no. 12 (2020): 2361. http://dx.doi.org/10.3390/ani10122361.
Full textAbstract:
Cercarial dermatitis, or Swimmer’s itch, is one of the emerging diseases caused by the cercariae of water-borne schistosomes, mainly Trichobilharzia spp. Since the zoonotic potential of Allobilharzia visceralis is still unknown, studies on this schistosome would be helpful to add knowledge on its possible role in causing human infections. In the present study, 54 whooper swans (Cygnus cygnus) from rescue/rehabilitation centers in Honshu, Japan, were necropsied to identify the cause of death. Grossly, 33 (61.11%) swans were severely emaciated and 23 (42.59%) had multiple reddened areas throughout the length of the intestine with no worms detected in the internal organs. Microscopically, adult schistosomes were found in the lumen of the mesenteric, serosal, portal, and testicular veins, in the capillaries of the intestinal lamina propria, and in the sinusoids of the adrenal gland, spleen, and liver of 23 (42.59%) swans. Hypertrophy of veins containing adult worms was identified in 15 (27.77%) swans, and vascular lumen obliteration was observed in 8 (14.81%) swans. Mild to severe villous atrophy and superficial enteritis were observed in 8 birds (14.81%), whereas bile pigments and hemosiderin were detected in the livers of 14 (25.92%) and 18 (33.33%) swans, respectively. In three swans (5.55%), schistosome parasites were found in the subcapsular veins of the testes. The schistosomes in the present study were assumed to be A. visceralis based on the microscopical and histological evidence of adult schistosomes found in the lumen of veins as well as the infection pathology, which was very similar to the schistosome-induced pathology previously reported in swans infected by A. visceralis in Europe and Australia. The swans examined herein most likely died from obstructive phlebitis associated with A. visceralis, but further molecular confirmation is required for identification of this species. However, the present study does not provide new data on the zoonotic potential, but only on the pathogenic potential of this schistosome in swans. Furthermore, our study provides a novel contribution to the description of the pathological effects of avian schistosomes infection in whooper swans in Japan.
18
Wood, Stephanie, Kenji Ishida, James R. Hagerty, Anida Karahodza, Janay N. Dennis, and Emmitt R. Jolly. "Characterization of Schistosome Sox Genes and Identification of a Flatworm Class of Sox Regulators." Pathogens 12, no. 5 (2023): 690. http://dx.doi.org/10.3390/pathogens12050690.
Full textAbstract:
Schistosome helminths infect over 200 million people across 78 countries and are responsible for nearly 300,000 deaths annually. However, our understanding of basic genetic pathways crucial for schistosome development is limited. The sex determining region Y-box 2 (Sox2) protein is a Sox B type transcriptional activator that is expressed prior to blastulation in mammals and is necessary for embryogenesis. Sox expression is associated with pluripotency and stem cells, neuronal differentiation, gut development, and cancer. Schistosomes express a Sox-like gene expressed in the schistosomula after infecting a mammalian host when schistosomes have about 900 cells. Here, we characterized and named this Sox-like gene SmSOXS1. SmSoxS1 protein is a developmentally regulated activator that localizes to the anterior and posterior ends of the schistosomula and binds to Sox-specific DNA elements. In addition to SmSoxS1, we have also identified an additional six Sox genes in schistosomes, two Sox B, one SoxC, and three Sox genes that may establish a flatworm-specific class of Sox genes with planarians. These data identify novel Sox genes in schistosomes to expand the potential functional roles for Sox2 and may provide interesting insights into early multicellular development of flatworms.
19
HOLA-JAMRISKA, L., J. P. DALTON, J. AASKOV, and P. J. BRINDLEY. "Dipeptidyl peptidase I and III activities of adult schistosomes." Parasitology 118, no. 3 (1999): 275–82. http://dx.doi.org/10.1017/s0031182098003746.
Full textAbstract:
Soluble extracts of adult Schistosoma japonicum and S. mansoni were examined for the presence of proteolytic activities ascribable to dipeptidyl peptidases (DPPs) at a range of pH from 4 to 11 using synthetic peptidyl substrates diagnostic of DPPs I, II, III and IV. Activity capable of cleaving the DPP I-specific substrates H-Gly-Arg-NHMec and H-Gly-Phe-NHMec which exhibited a pH optimum of 5·5 was observed in extracts of schistosomes. Female schistosomes exhibited greater DPP I activity than male schistosomes, while female S. japonicum showed substantially more activity than female S. mansoni. The specific activities against H-Gly-Arg-NHMec were 21·5 and 1·9 nmoles NHMec/min/mg protein for female and male S. japonicum and 8·5 and 1·9 nmoles NHMec/min/mg for female and male S. mansoni. The biochemical properties of schistosome DPP I were similar to mammalian DPP I (=cathepsin C) in that schistosome DPP I was only slowly inhibited by the cysteine protease inhibitor trans-epoxysuccinyl-1-leucylamido (4-guanidino)- butane, partly inhibited by the blocked diazomethyl ketones Z-Phe-Ala-CHN2 and Z-Phe-Phe-CHN2, but enhanced by halide ions. At pH 8·5, activity against the DPP III-specific substrate H-Arg-Arg-NHMec was evident in schistosome extracts, and this activity appeared to be due to a zinc metallo-exopeptidase because it was inhibited by 1,10-phenathroline and by EDTA. DPP II or DPP IV activity was not detected in the schistosome extracts.
20
Zhu, Peng, Kaijuan Wu, Chaobin Zhang, et al. "Advances in new target molecules against schistosomiasis: A comprehensive discussion of physiological structure and nutrient intake." PLOS Pathogens 19, no. 7 (2023): e1011498. http://dx.doi.org/10.1371/journal.ppat.1011498.
Full textAbstract:
Schistosomiasis, a severe parasitic disease, is primarily caused by Schistosoma mansoni, Schistosoma japonicum, or Schistosoma haematobium. Currently, praziquantel is the only recommended drug for human schistosome infection. However, the lack of efficacy of praziquantel against juvenile worms and concerns about the emergence of drug resistance are driving forces behind the research for an alternative medication. Schistosomes are obligatory parasites that survive on nutrients obtained from their host. The ability of nutrient uptake depends on their physiological structure. In short, the formation and maintenance of the structure and nutrient supply are mutually reinforcing and interdependent. In this review, we focus on the structural features of the tegument, esophagus, and intestine of schistosomes and their roles in nutrient acquisition. Moreover, we introduce the significance and modes of glucose, lipids, proteins, and amino acids intake in schistosomes. We linked the schistosome structure and nutrient supply, introduced the currently emerging targets, and analyzed the current bottlenecks in the research and development of drugs and vaccines, in the hope of providing new strategies for the prevention and control of schistosomiasis.
21
Al-Kandari, W. Y., S. A. Al-Bustan, A. M. Isaac, B. A. George, and B. S. Chandy. "Molecular identification ofAustrobilharziaspecies parasitizingCerithidea cingulata(Gastropoda: Potamididae) from Kuwait Bay." Journal of Helminthology 86, no. 4 (2011): 470–78. http://dx.doi.org/10.1017/s0022149x11000733.
Full textAbstract:
AbstractAvian schistosomes belonging to the genusAustrobilharzia(Digenea: Schistosomatidae) are among the causative agents of cercarial dermatitis in humans. In this paper, ribosomal and mitochondrial DNA sequences were used to study schistosome cercariae from Kuwait Bay that have been identified morphologically asAustrobilharziasp. Sequence comparison of the ribosomal DNA (rDNA) 28S and 18S regions of the collected schistosome cercariae with corresponding sequences of other schistosomes in GenBank revealed high sequence similarity. This confirmed the morphological identification of schistosome cercariae from Kuwait Bay as belonging to the genusAustrobilharzia. The finding was further supported by the phylogenetic tree that was constructed based on the combined data set 18S-28S-mitochondrial cytochrome oxidase I (mtCO1) sequences in whichAustrobilharziasp. clustered withA. terrigalensisandA. variglandis. Sequence comparison of theAustrobilharziasp. from Kuwait Bay withA. variglandisandA. terrigalensisbased on mtCO1 showed a variation of 10% and 11%, respectively. Since the sequence variation in the mtCO1 was within the interspecific range among trematodes, it seems that theAustrobilharziaspecies from Kuwait Bay is different from the two species reported in GenBank,A.terrigalensisandA. variglandis.
22
ROLLINSON, DAVID, JOANNE P. WEBSTER, BONNIE WEBSTER, SILVESTER NYAKAANA, ASLAK JØRGENSEN, and J. RUSSELL STOTHARD. "Genetic diversity of schistosomes and snails: implications for control." Parasitology 136, no. 13 (2009): 1801–11. http://dx.doi.org/10.1017/s0031182009990412.
Full textAbstract:
SUMMARYMolecular approaches are providing new insights into the genetic diversity of schistosomes and their intermediate snail hosts. For instance, molecular tools based on the polymerase chain reaction are being developed for the diagnosis of schistosomiasis and the detection of prepatent schistosome infections in snails at transmission sites. Robust phylogenies of the different species of Schistosoma, Bulinus and Biomphalaria have been determined and novel methods are available to identify the different and cryptic taxa involved. Microsatellite analyses and mitochondrial DNA sequencing methods have been developed and are contributing to a better understanding of the genetic structure of both schistosome and snail populations. New sampling procedures to capture DNA of eggs and larval stages of schistosomes in field situations are facilitating more detailed and ethically advantageous studies on parasite heterogeneity. Knowledge of the genetic diversity of schistosome and snail populations adds a further dimension to the monitoring and surveillance of disease, and the implementation of new molecular-based approaches will be of increasing importance in helping to assess the impact of schistosomiasis control strategies.
23
BROUWERS, Jos F. H. M., Cornelis VERSLUIS, Lambert M. G. van GOLDE, and Aloysius G. M. TIELENS. "5-Octadecenoic acid: evidence for a novel type of fatty acid modification in schistosomes." Biochemical Journal 334, no. 2 (1998): 315–19. http://dx.doi.org/10.1042/bj3340315.
Full textAbstract:
The lipid metabolism of schistosomes is characterized by several intriguing adaptations to a parasitic way of living. The surface of the parasite consists of two closely apposed phospholipid bilayers, a structure unique to blood flukes. Schistosomes do not synthesize fatty acids de novo, but are able to modify fatty acids, which they obtain from the host, by chain elongation. Here we present evidence that schistosomes are capable of another type of fatty acid modification, resulting in the formation of 5-octadecenoic acid [C18:1(5)]. This highly unusual fatty acid, which is absent in the blood of the host, was shown to be almost exclusively located in the outer membrane complex of the schistosome. Within these membranes, it was almost exclusively present in one molecular phospholipid species, 1-palmitoyl-2,5-octadecenoyl phosphatidylcholine [C16:0–18:1(5)PtdCho]. Apart from dipalmitoyl phosphatidylcholine, this was the most abundant phosphatidylcholine species in the outer membrane complex. The specific synthesis by the schistosome of C18:1(5) and the highly specific localization of this fatty acid to the tegumental membranes suggest an important tegument-mediated role for this lipid.
24
Stanicka, Anna, Łukasz Migdalski, Kamila Stefania Zając, Anna Cichy, Dorota Lachowska-Cierlik, and Elżbieta Żbikowska. "The genus Bilharziella vs. other bird schistosomes in snail hosts from one of the major recreational lakes in Poland." Knowledge & Management of Aquatic Ecosystems, no. 422 (2021): 12. http://dx.doi.org/10.1051/kmae/2021013.
Full textAbstract:
Bird schistosomes are commonly established as the causative agent of swimmer's itch − a hyper-sensitive skin reaction to the penetration of their infective larvae. The aim of the present study was to investigate the prevalence of the genus Bilharziella in comparison to other bird schistosome species from Lake Drawsko − one of the largest recreational lakes in Poland, struggling with the huge problem of swimmer's itch. In total, 317 specimens of pulmonate snails were collected and examined. The overall digenean infection was 35.33%. The highest bird schistosome prevalence was observed for Bilharziella sp. (4.63%) in Planorbarius corneus, followed by Trichobilharzia szidati (3.23%) in Lymnaea stagnalis and Trichobilharzia sp. (1.3%) in Stagnicola palustris. The location of Bilharziella sp. on the presented phylogeny showed that it is with high probability a different species than known so far B. polonica. Our finding complements the confirmed occurrence of bird schistosomes in European water bodies. Overall, presented research reveals the special importance of P. corneus as a source of the bird schistosome cercariae. This study suggests that the health threat connected with the blood flukes need to be further investigated by constant monitoring of their occurrence in intermediate hosts.
25
CURTIS, J., R. E. SORENSEN, and D. J. MINCHELLA. "Schistosome genetic diversity: the implications of population structure as detected with microsatellite markers." Parasitology 125, no. 7 (2002): S51—S59. http://dx.doi.org/10.1017/s0031182002002020.
Full textAbstract:
Blood flukes in the genus Schistosoma are important human parasites in tropical regions. A substantial amount of genetic diversity has been described in populations of these parasites using molecular markers. We first consider the extent of genetic variation found in Schistosoma mansoni and some factors that may be contributing to this variation. Recently, though, attempts have been made to analyze not only the genetic diversity but how that diversity is partitioned within natural populations of schistosomes. Studies with non-allelic molecular markers (e.g. RAPDs and mtVNTRs) have indicated that schistosome populations exhibit varying levels of gene flow among component subpopulations. The recent characterization of microsatellite markers for S. mansoni provided an opportunity to study schistosome population structure within a population of schistosomes from a single Brazilian village using allelic markers. Whereas the detection of population structure depends strongly on the type of analysis with a mitochondrial marker, analyses with a set of seven microsatellite loci consistently revealed moderate genetic differentiation when village boroughs were used to define parasite subpopulations and greater subdivision when human hosts defined subpopulations. Finally, we discuss the implications that such strong population structure might have on schistosome epidemiology.
26
LoVerde, Philip T., Edward G. Niles, Ahmed Osman, and Wenjie Wu. "Schistosoma mansoni male–female interactions." Canadian Journal of Zoology 82, no. 2 (2004): 357–74. http://dx.doi.org/10.1139/z03-217.
Full textAbstract:
Schistosome parasites are muticellular eucaryotic organisms with a complex life cycle that involves mammalian and snail hosts. Unlike other trematode parasites, schistosomes (along with the Didymozoidae) have evolved separate sexes or dioecy. Sex is determined by a chromosomal mechanism. The dioecious state created an opportunity for the sexes to play a role in schistosome evolution that has resulted in an interesting interplay between the sexes. The classical observation, made more than 50 years ago, is that female schistosomes do not develop unless a male worm is present. Studies up through the 1990s focused on dissecting the role of the sexes in mate attraction, mate choice, mating behavior, female growth, female reproductive development, egg production, and other sex-evolved functions. In the mid-1980s, studies began to address the molecular events of male–female interactions. The classic morphological observation that female schistosomes do not complete reproductive development unless a male worm is present has been redefined in molecular terms. The male by an unknown mechanism transduces a signal that regulates female gene expression in a stage-, tissue-, and temporal-specific manner. A number of female-specific genes have been identified, along with signaling pathways and nuclear receptors, that play a role in female reproductive development. In addition, a number of host factors such as cytokines have also been demonstrated to affect adult male and female development and egg production. This review focuses on the biological interactions of the male and female schistosome and the role of parasite and host factors in these interactions as they contribute to the life cycle of Schistosoma mansoni.
27
Ibikounlé, M., L. G. Gbédjissi, A. Ogouyèmi-Hounto, W. Batcho, D. Kindé-Gazard, and A. Massougbodji. "Schistosomose et géohelminthoses dans le nord-est du Bénin : cas des écoliers des communes de Nikki et de Pèrèrè." Bulletin de la Société de pathologie exotique 107, no. 3 (2014): 171–76. http://dx.doi.org/10.1007/s13149-014-0344-y.
Full text
28
Diop, Amadou Tamsir, O. T. Diaw, Ibrahima Dieme, Ibra Touré, Oumar Sy, and G. Diémé. "Mares de la zone sylvopastorale du Sénégal : tendances évolutives et rôle dans les stratégies de production des populations pastorales." Revue d’élevage et de médecine vétérinaire des pays tropicaux 57, no. 1-2 (2004): 77. http://dx.doi.org/10.19182/remvt.9910.
Full textAbstract:
La zone sylvopastorale du Sénégal, comme la plupart des régions sahéliennes d’Afrique, est une zone où le problème de l’eau se pose avec acuité. Les mares y sont cependant nombreuses. Du début à la fin de la saison des pluies, elles sont fréquentées par une population humaine et animale dont l’importance n’a pas baissé en dépit d’un important programme d’hydraulique basé sur l’exploitation des nappes profondes. Ces mares continuent donc à être utilisées jusqu’à la dernière goutte d’eau par différentes techniques. Mais, de plus en plus, des changements au niveau de leur capacité d’accumulation d’eau ou de la qualité de l’eau sont notés. La prévalence de la schistosomose humaine et animale est pour l’instant faible mais le mollusque, l’hôte intermédiaire, et le parasite sont présents, notamment dans la partie sud de la zone étudiée. Du fait des difficultés de plus en plus importantes notées dans la gestion des ouvrages hydrauliques (forages et puits), les pouvoirs publics ont initié un programme de remise en eau des bassins versants depuis une décennie. Le présent article est une contribution à la mise en oeuvre de ce programme dont l’aménagement des mares constitue une activité très importante en zone sylvopastorale.
29
MANN, VICTORIA H., MARIA E. MORALES, GABRIEL RINALDI, and PAUL J. BRINDLEY. "Culture for genetic manipulation of developmental stages of Schistosoma mansoni." Parasitology 137, no. 3 (2009): 451–62. http://dx.doi.org/10.1017/s0031182009991211.
Full textAbstract:
SUMMARYGenomes of the major human helminth parasites, and indeed many others of agricultural significance, are now the research focus of intensive genome sequencing and annotation. A draft genome sequence of the filarial parasite Brugia malayi was reported in 2007 and draft genomes of two of the human schistosomes, Schistosoma japonicum and S. mansoni reported in 2009. These genome data provide the basis for a comprehensive understanding of the molecular mechanisms involved in schistosome nutrition and metabolism, host-dependent development and maturation, immune evasion and invertebrate evolution. In addition, new potential vaccine candidates and drug targets will likely be predicted. However, testing these predictions is often not straightforward with schistosomes because of the difficulty and expense in maintenance of the developmental cycle. To facilitate this goal, several developmental stages can be maintained in vitro for shorter or longer intervals of time, and these are amenable to manipulation. Our research interests focus on experimental studies of schistosome gene functions, and more recently have focused on development of transgenesis and RNA interference with the longer term aim of heritable gene manipulation. Here we review methods to isolate and culture developmental stages of Schistosoma mansoni, including eggs, sporocysts, schistosomules and adults, in particular as these procedures relate to approaches for gene manipulation. We also discuss recent advances in genetic manipulation of schistosomes including the deployment of square wave electroporation to introduce reporter genes into cultured schistosomes.
30
Ashrafi, Keyhan, Meysam Sharifdini, Abbas Darjani, and Sara V. Brant. "Migratory routes, domesticated birds and cercarial dermatitis: the distribution of Trichobilharzia franki in Northern Iran." Parasite 28 (2021): 4. http://dx.doi.org/10.1051/parasite/2020073.
Full textAbstract:
Background: One of the major migration routes for birds going between Europe and Asia is the Black Sea-Mediterranean route that converges on the Volga Delta, continuing into the area of the Caspian Sea. Cercarial dermatitis is a disorder in humans caused by schistosome trematodes that use aquatic birds and snails as hosts and is prevalent in areas of aquaculture in Northern Iran. Before the disorder can be addressed, it is necessary to determine the etiological agents and their host species. This study aimed to document whether domestic mallards are reservoir hosts and if so, to characterize the species of schistosomes. Previous work has shown that domestic mallards are reservoir hosts for a nasal schistosome. Results: In 32 of 45 domestic mallards (Anas platyrhynchos domesticus) (71.1%), the schistosome Trichobilharzia franki, previously reported only from Europe, was found in visceral veins. Morphological and molecular phylogenetic analysis confirmed the species designation. These findings extend the range of T. franki from Europe to Eurasia. Conclusion: The occurrence of cercarial dermatitis in Iran is high in areas of aquaculture. Previous studies in the area have shown that domestic mallards are reservoir hosts of T. regenti, a nasal schistosome and T. franki, as shown in this study. The genetic results support the conclusion that populations of T. franki from Iran are not differentiated from populations in Europe. Therefore, the schistosomes are distributed with their migratory duck hosts, maintaining the gene flow across populations with compatible snail hosts in Iran.
31
Adema, C. M., E. C. Van Deutekom-Mulder, W. P. W. Van Der Knaap, and T. Sminia. "Schistosomicidal activities ofLymnaea stagnalishaemocytes: the role of oxygen radicals." Parasitology 109, no. 4 (1994): 479–85. http://dx.doi.org/10.1017/s0031182000080732.
Full textAbstract:
SUMMARYMacrophage-like defence cells (haemocytes) of the pond snailLymnaea stagnalismediate cytotoxicity through reactive oxygen intermediates (ROIs). This activity is NADPH-oxidase dependent, as in mammalian phagocytes during the respiratory burst. In this study, mother sporocysts of schistosomes, the compatibleTrichobilharzia ocellataand the incompatibleSchistosoma mansonievokein vitroROI activities (detected by luminol dependent chemiluminescence, LDCL) fromL. stagnalishaemocytes.S. mansoniis encapsulated by haemocytes and eliminated, whereasT. ocellataescapes encapsulation and survives. Both schistosomes were equally susceptible toin vitrooxidative damage from exposure to hydrogen peroxide and to ROIs generated by a xanthine/xanthine oxidase system. Protocatechuic acid, a specific antagonist of NADPH-oxidase, delayed the killing ofT. ocellataandS. mansonisporocysts by haemocytes of resistant snails (Biomphalaria glabrata and L. stagnalis, respectively). We conclude that ROIs take part in haemocyte-mediated cytotoxicity. However, neither a snail's capability to generate ROIs, nor a schistosome's susceptibility to ROIs, determine snail/schistosome incompatibility. Snail/schistosome compatibility is rather determined by the parasite's ability modulate haemocyte behaviour such that effective encapsulation and the generation of lethal concentrations of ROIs are prevented.
32
Brant, S. V., K. Pomajbíková, D. Modry, K. J. Petrželková, A. Todd, and E. S. Loker. "Molecular phylogenetics of the elephant schistosome Bivitellobilharzia loxodontae (Trematoda: Schistosomatidae) from the Central African Republic." Journal of Helminthology 87, no. 1 (2012): 102–7. http://dx.doi.org/10.1017/s0022149x1200003x.
Full textAbstract:
AbstractOne of the most poorly known of all schistosomes infecting mammals is Bivitellobilharzia loxodontae. Nearly all of our available information about this species comes from the original description of worms that were obtained from an animal park-maintained elephant in Germany, probably a forest elephant Loxodonta cyclotis, originating from the present-day Democratic Republic of Congo. We obtained schistosome eggs from faecal samples from wild forest elephants from the Central African Republic. The eggs, which were similar in size and shape to those of described B. loxodontae, were sequenced for the 28S nuclear ribosomal gene and the mitochondrial cytochrome oxidase I (cox1) gene. In a phylogenetic analysis of 28S sequences, our specimens grouped closely with B. nairi, the schistosome from the Indian elephant Elephas maximus, to the exclusion of schistosomes from other genera. However, the eggs were genetically distinct (12% distance cox1) from those of B. nairi. We conclude the specimens we recovered were of B. loxodontae and confirm this is a distinct Bivitellobilharzia species. In addition to providing the first sequence data for B. loxodontae, this report also supports Bivitellobilharzia as a monophyletic group and gives the relative phylogenetic position of the genus within the Schistosomatidae. We also provide a review of the biology of this poorly known schistosome genus.
33
BECKMANN, S., and C. G. GREVELDING. "Paving the way for transgenic schistosomes." Parasitology 139, no. 5 (2011): 651–68. http://dx.doi.org/10.1017/s0031182011001466.
Full textAbstract:
SUMMARYIn parasitological research, significant progress has been made with respect to genomics and transcriptomics but transgenic systems for functional gene analyses are mainly restricted to the protozoan field. Gene insertion and knockout strategies can be applied to parasitic protozoa as well as gene silencing by RNA interference (RNAi). By contrast, research on parasitic helminthes still lags behind. Along with the major advances in genome and transcriptome analyses e.g. for schistosomes, methods for the functional characterization of genes of interest are still in their initial phase and have to be elaborated now, at the beginning of the post-genomic era. In this review we will summarize attempts made in the last decade regarding the establishment of protocols to transiently and stably transform or transfect schistosomes. Besides approaches using particle bombardment, electroporation or virus-based infection strateies to introduce DNA constructs into adult and larval schistosome stages to express reporter genes, first approaches have also been made in establishing protocols based on soaking, lipofection, and/or electroporation for RNA interference to silence gene activity. Although in these cases remarkable progress can be seen, the schistosome community eagerly awaits major breakthroughs especially with respect to stable transformation, but also for silencing or knock-down strategies for every schistosome gene of interest.
34
Padalino, Gilda, Avril Coghlan, Giampaolo Pagliuca, Josephine E. Forde-Thomas, Matthew Berriman, and Karl F. Hoffmann. "Using ChEMBL to Complement Schistosome Drug Discovery." Pharmaceutics 15, no. 5 (2023): 1359. http://dx.doi.org/10.3390/pharmaceutics15051359.
Full textAbstract:
Schistosomiasis is one of the most important neglected tropical diseases. Until an effective vaccine is registered for use, the cornerstone of schistosomiasis control remains chemotherapy with praziquantel. The sustainability of this strategy is at substantial risk due to the possibility of praziquantel insensitive/resistant schistosomes developing. Considerable time and effort could be saved in the schistosome drug discovery pipeline if available functional genomics, bioinformatics, cheminformatics and phenotypic resources are systematically leveraged. Our approach, described here, outlines how schistosome-specific resources/methodologies, coupled to the open-access drug discovery database ChEMBL, can be cooperatively used to accelerate early-stage, schistosome drug discovery efforts. Our process identified seven compounds (fimepinostat, trichostatin A, NVP-BEP800, luminespib, epoxomicin, CGP60474 and staurosporine) with ex vivo anti-schistosomula potencies in the sub-micromolar range. Three of those compounds (epoxomicin, CGP60474 and staurosporine) also demonstrated potent and fast-acting ex vivo effects on adult schistosomes and completely inhibited egg production. ChEMBL toxicity data were also leveraged to provide further support for progressing CGP60474 (as well as luminespib and TAE684) as a novel anti-schistosomal compound. As very few compounds are currently at the advanced stages of the anti-schistosomal pipeline, our approaches highlight a strategy by which new chemical matter can be identified and quickly progressed through preclinical development.
35
SUTTIPRAPA, SUTAS, GABRIEL RINALDI, and PAUL J. BRINDLEY. "Genetic manipulation of schistosomes – progress with integration competent vectors." Parasitology 139, no. 5 (2011): 641–50. http://dx.doi.org/10.1017/s003118201100134x.
Full textAbstract:
SUMMARYDraft genome sequences forSchistosoma japonicumandS. mansoniare now available. The schistosome genome encodes ∼13 000 protein-encoding genes for which the functions of few are well understood. Nonetheless, the new genes represent potential intervention targets, and molecular tools are being developed to determine their importance. Over the past 15 years, noteworthy progress has been achieved towards development of tools for gene manipulation and transgenesis of schistosomes. A brief history of genetic manipulation is presented, along with a review of the field with emphasis on reports of integration of transgenes into schistosome chromosomes.
36
Ibikounlé, M., A. Ogouyèmi-Hounto, Y. Sissinto Savi de Tové, et al. "Épidémiologie de la schistosomose urinaire chez les enfants scolarisés de la commune de Péhunco dans le Nord Bénin : prospection malacologique." Bulletin de la Société de pathologie exotique 107, no. 3 (2014): 177–84. http://dx.doi.org/10.1007/s13149-014-0345-x.
Full text
37
Brady, Ciaran P., Andrew J. Dowd, Paul J. Brindley, Thecla Ryan, Sharon R. Day, and John P. Dalton. "Recombinant Expression and Localization ofSchistosoma mansoni Cathepsin L1 Support Its Role in the Degradation of Host Hemoglobin." Infection and Immunity 67, no. 1 (1999): 368–74. http://dx.doi.org/10.1128/iai.67.1.368-374.1999.
Full textAbstract:
ABSTRACT Cysteine proteinases expressed by schistosomes appear to play key roles in the digestion of host hemoglobin, the principal source of amino acid nutrients utilized by these parasites. We have shown previously that the predominant cysteine proteinase activity in soluble extracts and excretory/secretory (ES) products of adults ofSchistosoma mansoni and S. japonicum is cathepsin L-like in its substrate specificity. However, biochemical analysis of the cathepsin L activity in extracts and ES products of schistosomes has been complicated by the presence of at least two distinct forms of schistosome cathepsin L, termed SmCL1 and SmCL2. We now report the purification and enzyme characteristics of active, recombinant SmCL1 which was obtained by transformingSaccharomyces cerevisiae with an expression plasmid encoding the preproenzyme of SmCL1. Recombinant SmCL1 was secreted by the transformed yeast into the culture media from which it was purified by gel filtration and ion-exchange chromatography. The purified enzyme exhibited substrate specificity against synthetic peptidyl substrates (e.g., Boc-Val-Leu-Lys-NHMec and Z-Phe-Arg-NHMec;k cat/Km = 17.25 and 6.24 mM−1 s−1, respectively) and against gelatin and hemoglobin, characteristic of cathepsin L. Immunoblot analysis using antiserum raised against recombinant SmCL1 demonstrated that native SmCL1 of 33 kDa was present in ES products and soluble extracts of S. mansoni. Using this antiserum and thin tissue sections, we localized the native SmCL1 to the gastrodermis and to the tegument of adult schistosomes. Recombinant SmCL1 was capable of degrading human hemoglobin at pH 4.0 to 4.5 but not higher, suggesting that denaturation of hemoglobin by low pH, as found in the cecum of the adult schistosome, may be necessary for its catalysis by cathepsin L and other gut-associated proteinases. Together, these results support a role for SmCL1 in the degradation of host hemoglobin within the gut of the schistosome.
38
Webb, Alexander James, Fiona Allan, Richard J. R. Kelwick, et al. "Specific Nucleic AcId Ligation for the detection of Schistosomes: SNAILS." PLOS Neglected Tropical Diseases 16, no. 7 (2022): e0010632. http://dx.doi.org/10.1371/journal.pntd.0010632.
Full textAbstract:
Schistosomiasis, also known as bilharzia or snail fever, is a debilitating neglected tropical disease (NTD), caused by parasitic trematode flatworms of the genus Schistosoma, that has an annual mortality rate of 280,000 people in sub-Saharan Africa alone. Schistosomiasis is transmitted via contact with water bodies that are home to the intermediate host snail which shed the infective cercariae into the water. Schistosome lifecycles are complex, and while not all schistosome species cause human disease, endemic regions also typically feature animal-infecting schistosomes that can have broader economic and/or food security implications. Therefore, the development of species-specific Schistosoma detection technologies may help to inform evidence-based local environmental, food security and health systems policy making. Crucially, schistosomiasis disproportionally affects low- and middle-income (LMIC) countries and for that reason, environmental screening of water bodies for schistosomes may aid with the targeting of water, sanitation, and hygiene (WASH) interventions and preventive chemotherapy to regions at highest risk of schistosomiasis transmission, and to monitor the effectiveness of such interventions at reducing the risk over time. To this end, we developed a DNA-based biosensor termed Specific Nucleic AcId Ligation for the detection of Schistosomes or ‘SNAILS’. Here we show that ‘SNAILS’ enables species-specific detection from genomic DNA (gDNA) samples that were collected from the field in endemic areas.
39
Nahum, Laila A., Marina M. Mourão, and Guilherme Oliveira. "New Frontiers inSchistosomaGenomics and Transcriptomics." Journal of Parasitology Research 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/849132.
Full textAbstract:
Schistosomes are digenean blood flukes of aves and mammals comprising 23 species. Some species are causative agents of human schistosomiasis, the second major neglected disease affecting over 230 million people worldwide. Modern technologies including the sequencing and characterization of nucleic acids and proteins have allowed large-scale analyses of parasites and hosts, opening new frontiers in biological research with potential biomedical and biotechnological applications. Nuclear genomes of the three most socioeconomically important species (S. haematobium,S. japonicum, andS. mansoni) have been sequenced and are under intense investigation. Mitochondrial genomes of sixSchistosomaspecies have also been completely sequenced and analysed from an evolutionary perspective. Furthermore, DNA barcoding of mitochondrial sequences is used for biodiversity assessment of schistosomes. Despite the efforts in the characterization ofSchistosomagenomes and transcriptomes, many questions regarding the biology and evolution of this important taxon remain unanswered. This paper aims to discuss some advances in the schistosome research with emphasis on genomics and transcriptomics. It also aims to discuss the main challenges of the current research and to point out some future directions in schistosome studies.
40
Masamba, Priscilla, and Abidemi Paul Kappo. "Immunological and Biochemical Interplay between Cytokines, Oxidative Stress and Schistosomiasis." International Journal of Molecular Sciences 22, no. 13 (2021): 7216. http://dx.doi.org/10.3390/ijms22137216.
Full textAbstract:
The host–parasite schistosome relationship relies heavily on the interplay between the strategies imposed by the schistosome worm and the defense mechanisms the host uses to counter the line of attack of the parasite. The ultimate goal of the schistosome parasite entails five important steps: evade elimination tactics, survive within the human host, develop into adult forms, propagate in large numbers, and transmit from one host to the next. The aim of the parasitized host on the other hand is either to cure or limit infection. Therefore, it is a battle between two conflicting aspirations. From the host’s standpoint, infection accompanies a plethora of immunological consequences; some are set in place to defend the host, while most end up promoting chronic disease, which ultimately crosses paths with oxidative stress and cancer. Understanding these networks provides attractive opportunities for anti-schistosome therapeutic development. Hence, this review discusses the mechanisms by which schistosomes modulate the human immune response with ultimate links to oxidative stress and genetic instability.
41
CHENG, GUOFENG, and YOUXIN JIN. "MicroRNAs: Potentially important regulators for schistosome development and therapeutic targets against schistosomiasis." Parasitology 139, no. 5 (2012): 669–79. http://dx.doi.org/10.1017/s0031182011001855.
Full textAbstract:
SUMMARYMicroRNAs (miRNAs) are small, endogenous non-coding RNA molecules that regulate gene expression post-transcriptionally by targeting the 3′ untranslated region (3′ UTR) of messenger RNAs. Since the discovery of the first miRNA in Caenorhabditis elegans, important regulatory roles for miRNAs in many key biological processes including development, cell proliferation, cell differentiation and apoptosis of many organisms have been described. Hundreds of miRNAs have been identified in various multicellular organisms and many are evolutionarily conserved. Schistosomes are multi-cellular eukaryotes with a complex life-cycle that require genes to be expressed and regulated precisely. Recently, miRNAs have been identified in two major schistosome species, Schistosoma japonicum and S. mansoni. These miRNAs are likely to play critical roles in schistosome development and gene regulation. Here, we review recent studies on schistosome miRNAs and discuss the potential roles of miRNAs in schistosome development and gene regulation. We also summarize the current status for targeting miRNAs and the potential of this approach for therapy against schistosomiasis.
42
ZELCK, U. E., and B. VON JANOWSKY. "Antioxidant enzymes in intramolluscanSchistosoma mansoniand ROS-induced changes in expression." Parasitology 128, no. 5 (2004): 493–501. http://dx.doi.org/10.1017/s0031182004004895.
Full textAbstract:
Killing of intramolluscan schistosomes by host haemocytes is mediated by reactive oxygen metabolites. Hence, defence against oxidative damage is essential for the parasite to survive. In this study, expression of three key antioxidant enzymes, superoxide dismutase (EC 1.15.1.1), glutathione peroxidase (EC 1.11.1.9) and glutathione-S-transferase (EC 2.5.1.18) was determined inSchistosoma mansonimiracidia, sporocysts and cercariae. Stage-dependent expression of these enzymes was shown to be regulated at the transcriptional level. Second, the influence on enzyme expression of reactive oxygen species (ROS) and of haemocytes from schistosome-resistant and -susceptible host snails was determined. Generation of ROS by xanthine/xanthine oxidase resulted in increased transcript levels for all three enzymes. Addition of hydrogen peroxide induced a significantly increased expression of GPx and SOD but not GST. Snail haemocytes induced an up-regulation of SOD and GPx at 12 and 18 h post-exposure, respectively. Susceptible haemocytes elicited a stronger induction of transcript expression than resistant haemocytes. After 36–48 h, SOD remained up-regulated in sporocysts encapsulated by haemocytes from susceptible hosts, whereas a down-regulation of SOD and GPx occurred in schistosomes encapsulated by haemocytes from resistant snails. These observations indicate that schistosomes express elevated levels of antioxidant enzymes in interaction with haemocytes from susceptible snail hosts in which they survive. On the other hand, haemocytes of resistant snails may interfere with reactive oxygen detoxification via down-regulation of schistosome antioxidant enzymes, thus shifting the balance towards parasite killing.
43
MUTAPI, FRANCISCA. "Helminth parasite proteomics: from experimental models to human infections." Parasitology 139, no. 9 (2012): 1195–204. http://dx.doi.org/10.1017/s0031182011002423.
Full textAbstract:
SUMMARYSchistosomiasis is a major human helminth infection endemic in developing countries. Urogenital schistosomiasis, caused by S. haematobium, is the most prevalent human schistosome disease in sub-Saharan Africa. Currently control of schistosome infection is by treatment of infected people with the anthelmintic drug praziquantel, but there are calls for continued efforts to develop a vaccine against the parasites. In order for successful vaccine development, it is necessary to understand the biology and molecular characteristics of the parasite. Ultimately, there is need to understand the nature and dynamics of the relationship between the parasite and the natural host. Thus, my studies have focused on molecular characterization of different parasite stages and integrating this information with quantitative approaches to investigate the nature and development of protective immunity against schistosomes in humans. Proteomics has proved a powerful tool in these studies allowing the proteins expressed by the parasite to be characterized at a molecular and immunological level. In this review, the application of proteomic approaches to understanding the human-schistosome relationship as well as testing specific hypotheses on the nature and development of schistosome-specific immune responses is discussed. The contribution of these approaches to informing schistosome vaccine development is highlighted.
44
Lakshmanan, B., K. Devada, S. Joseph, T. V. Aravindakshan, and L. Sabu. "Copro-PCR based detection of bovine schistosome infection in India." Journal of Helminthology 90, no. 1 (2015): 102–7. http://dx.doi.org/10.1017/s0022149x1400090x.
Full textAbstract:
AbstractSchistosomosis and amphistomosis are the two economically important and widely prevalent snail-borne trematode infections in grazing cattle of southern India. Acute infections are symptomatically similar and difficult to detect by routine microscopy for eggs. The present study was directed towards the development of a copro-polymerase chain reaction (copro-PCR) for detection of bovine schistosome species, using custom-designed primers targeting 18S and 28S ribosomal RNA as well as mitochondrial DNA. The study demonstrated the enhanced diagnostic specificity of mitochondrial DNA markers over ribosomal RNA genes as genus-specific probes to detect schistosomes. We developed a sensitive PCR assay using primers designed from mitochondrial DNA sequences targeting the partialrrnl(16S rRNA), tCys (transfer RNA for cysteine) and partialrrnS(12S rRNA) genes ofSchistosoma spindaleto specifically detect schistosome infection from faecal samples of naturally infected bovines. The salient findings of the work also throw light on to the high similarity of the ribosomal RNA gene sequences of schistosomes with those ofGastrothylax crumeniferandFischoederius elongatus,the most prevalent pouched amphistomes of the region. Further investigation has to be directed towards unravelling the complete gene sequences of 18S and 28S ribosomal RNA as well as mitochondrial DNA sequences of amphistome isolates from India.
45
WEBSTER, J. P., and C. M. DAVIES. "Coevolution and compatibility in the snail–schistosome system." Parasitology 123, no. 7 (2001): 41–56. http://dx.doi.org/10.1017/s0031182001008071.
Full textAbstract:
In stark contrast to the huge body of theoretical work on the importance of hosts and parasites as selective agents acting on each other, until recently, little systematic empirical investigation of this issue has been attempted. Research on snail–schistosome interactions have, therefore, the potential for making an important contribution to the study of coevolution or reciprocal adaptation. This may be particularly pertinent since snail–schistosomes represent an indirectly transmitted macroparasite system, so often overlooked amongst both theoretical and empirical studies. Here we review ideas and experiments on snail–schistosome interactions, with particular emphasis on those that may have relevance to the potential coevolution between host resistance and parasite infectivity and virulence. We commence with an introduction and definition of the general concepts, before going into detail of some specific studies to illustrate these: evidence of snail–schistosome coevolutionary process in the field; evidence of coevolutionary processes in the laboratory; a general assessment of the applicability of coevolutionary models in snail–schistosome interactions; and finishing with a section on conclusions and areas for further study.
46
CHENG, GUOFENG, RONG LUO, CHAO HU, JIE CAO, and YOUXIN JIN. "Deep sequencing-based identification of pathogen-specific microRNAs in the plasma of rabbits infected withSchistosoma japonicum." Parasitology 140, no. 14 (2013): 1751–61. http://dx.doi.org/10.1017/s0031182013000917.
Full textAbstract:
SUMMARYCirculating microRNAs (miRNAs) have received considerable attention as a novel class of biomarkers for the diagnosis of cancer and as signalling molecules in mediating intercellular communication. Schistosomes, the causative agents of schistosomiasis, live in the blood vessels of a mammalian host in the adult stage. In the present study, we characterized schistosome-specific small RNA populations in the plasma of rabbits infected withSchistosoma japonicum(S. japonicum) using a deep sequencing method and then identified five schistosome-specific miRNAs, including four known miRNAs (Bantam, miR-3479, miR-10 and miR-3096), and one novel miRNA (miR-0001, miRBase ID: sja-miR-8185). Four of the five schistosome-specific miRNAs were also detected by real-time RT–PCR in the plasma ofS. japonicum-infected mice. In addition, our study indicated that schistosome Argonaute 2/3 may be an excretory-secretory (ES) protein. In summary, our findings are expected to provide useful information for further development of novel biomarkers for the diagnosis of schistosomiasis and also for deeper understanding of the mechanism of host–parasite interaction.
47
DAVIES, C. M., J. P. WEBSTER, O. KRÜGER, A. MUNATSI, J. NDAMBA, and M. E. J. WOOLHOUSE. "Host–parasite population genetics: a cross-sectional comparison of Bulinus globosus and Schistosoma haematobium." Parasitology 119, no. 3 (1999): 295–302. http://dx.doi.org/10.1017/s0031182099004722.
Full textAbstract:
The genetic population structures of the freshwater snail Bulinus globosus and its trematode parasite Schistosoma haematobium from 8 river sites in the Zimbabwean highveld were compared using randomly amplified DNA(RAPD) markers. There was significant variability between snail populations collected at different sites, but schistosome populations only showed differentiation at a wider geographical scale (between 2 non-connected river systems). For snails, genetic distance was better correlated with proximity along rivers than absolute geographical separation. In contrast, schistosome genetic distance was better correlated with absolute geographical separation than proximity along rivers. These results are consistent with different dispersal mechanisms for snails and schistosomes and the implications for host–parasite coevolution are discussed.
48
Skírnisson, K., J. A. Aldhoun, and L. Kolářová. "A review on swimmer's itch and the occurrence of bird schistosomes in Iceland." Journal of Helminthology 83, no. 2 (2009): 165–71. http://dx.doi.org/10.1017/s0022149x09336408.
Full textAbstract:
AbstractIn the past decade, swimmer's itch (SI) has repeatedly occurred in people who have been wading or bathing in ponds or lakes in Iceland where water birds and snails are abundant. Some of the affected sites were warmed by geothermal activity, and others were not. A search for the causative agent of SI, ocellate furcocercariae that have been found in Iceland only in Radix peregra snails, revealed an average infection prevalence of 1.4% (n = 12,432). Locally, infection rates commonly exceeded 6%, the highest value observed being 24.5%. A search for adult schistosomes in visceral organs and the nasal cavities of 110 water birds belonging to the orders Gaviiformes, Podicipediformes and Anseriformes revealed eggs, miracidia or adult stages of at least seven previously identifiable schistosome species in four anseriform bird species. A previously unknown species of schistosome, Allobilharzia visceralis, was detected in whooper swans (Cygnus cygnus), and classified in a new genus. In mallards (Anas platyrhynchos) a nasal Trichobilharzia sp. and the visceral schistosome T. franki were identified. In red-breasted merganser (Mergus serrator), distinct egg types belonging to two species of the genus Trichobilharzia have been found. In grey-lag goose (Anser anser) two different egg types were also found – a large Trichobilharzia sp. and small eggs of a Dendritobilharzia sp. Additionally, unidentified cercariae, probably belonging to a previously undescribed genus were detected in R. peregra in Oslandsstjörn. Taken together, the data obtained by morphological examination of eggs and recent DNA sequencing results, indicate that at least eight species of bird schistosomes occur in Iceland.
49
HOFFMANN, K. F. "An historical and genomic view of schistosome conjugal biology with emphasis on sex-specific gene expression." Parasitology 128, S1 (2004): S11—S22. http://dx.doi.org/10.1017/s0031182004006213.
Full textAbstract:
The genetic programmes associated with the sexual biology of dioecious schistosomes remain a critically important but significantly understudied area of parasitology. Throughout the last four decades, progress has been slow in describing the gross antigenic and proteomic differences linked to sexually mature schistosomes and in characterizing some of the sex-associated transcripts and regulatory mechanisms induced during developmental maturation. These investigations have been severely hindered by the lack of complete EST/genomic information, as well as corresponding post- and functional-genomic tools for studying these pathogenic parasites. As near complete transcriptomes forSchistosoma japonicumandS. mansonihave recently been reported, and both DNA microarrays and post-transcriptional gene silencing have been applied to schistosomes, the tools and techniques for the high-throughput identification and characterization of transcripts involved in conjugal biology are now readily available. Here, an historical review is presented that summarizes some of the most significant findings associated with schistosome sex and sexual maturation during the last several decades. Following this discussion is a current overview of some modern day genomic approaches used to study schistosomes, which illustrates how major advances in the field of conjugal biology will be achieved.
50
Jouet, D., H. Ferté, C. Hologne, M. L. Kaltenbach, and J. Depaquit. "Avian schistosomes in French aquatic birds: a molecular approach." Journal of Helminthology 83, no. 2 (2009): 181–89. http://dx.doi.org/10.1017/s0022149x09311712.
Full textAbstract:
AbstractThe prevalence of human cercarial dermatitis (HCD) caused by bird schistosomes appears to be increasing in France, in light of the impact of tourism combined with high densities of wild aquatic hosts in freshwater areas. The present work expands our knowledge of schistosome systematics by including samples of bird schistosomes collected from their natural hosts in France. Heads (318) and viscera (81) of aquatic birds belonging to 16 species from five orders, collecting during the hunting seasons or found dead, were autopsied for nasal and visceral schistosomes. Eggs and/or adults were analysed by molecular methods using the D2 domain and the second internal transcribed spacer (ITS-2) region of rDNA to determine species. Even if nasal eggs were polymorphic according to the host, all haplotypes were similar to that of Trichobilharzia regenti. Marked diversity of visceral species was observed. Final hosts under natural conditions were reported. For the first time, Trichobilharzia franki is reported in its natural bird hosts, Anas platyrhynchos, Anas crecca, Aythya fuligula and Cygnus olor. We also identified T. szidati in A. crecca and Anas clypeata. Bilharziella polonica was found in six species of aquatic birds, including Grus grus. This finding is the first record of bird schistosomes in this aquatic bird. Three new taxa of visceral schistosomes in Anser anser are strongly suspected according to their haplotypes. Futhermore, a new haplotype of visceral schistosomes isolated in Cygnus olor and similar to Allobilharzia visceralis was identified.