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Bonnie L Webster - One of the best experts on this subject based on the ideXlab platform.
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Interactions between Schistosoma haematobium group species and their Bulinus spp. intermediate hosts along the Niger River Valley.
Parasites & vectors, 2020Co-Authors: Tom Pennance, Aidan M. Emery, David Rollinson, Fiona Allan, Muriel Rabone, Jo Cable, Amadou Garba, Amina Amadou Hamidou, Joanne P. Webster, Bonnie L WebsterAbstract:Urogenital schistosomiasis, caused by infection with Schistosoma haematobium, is endemic in Niger but complicated by the presence of Schistosoma bovis, Schistosoma curassoni and S. haematobium group hybrids along with various Bulinus snail intermediate host species. Establishing the schistosomes and snails involved in transmission aids disease surveillance whilst providing insights into snail-schistosome interactions/compatibilities and biology. Infected Bulinus spp. were collected from 16 villages north and south of the Niamey region, Niger, between 2011 and 2015. From each Bulinus spp., 20–52 cercariae shed were analysed using microsatellite markers and a subset identified using the mitochondrial (mt) cox1 and nuclear ITS1 + 2 and 18S DNA regions. Infected Bulinus spp. were identified using both morphological and molecular analysis (partial mt cox1 region). A total of 87 infected Bulinus from 24 sites were found, 29 were molecularly confirmed as B. truncatus, three as B. forskalii and four as B. globosus. The remaining samples were morphologically identified as B. truncatus (n = 49) and B. forskalii (n = 2). The microsatellite analysis of 1124 cercariae revealed 186 cercarial multilocus genotypes (MLGs). Identical cercarial genotypes were frequently (60%) identified from the same snail (clonal populations from a single miracidia); however, several (40%) of the snails had cercariae of different genotypes (2–10 MLG’s) indicating multiple miracidial infections. Fifty-seven of the B. truncatus and all of the B. forskalii and B. globosus were shedding the Bovid schistosome S. bovis. The other B. truncatus were shedding the human schistosomes, S. haematobium (n = 6) and the S. haematobium group hybrids (n = 13). Two B. truncatus had co-infections with S. haematobium and S. haematobium group hybrids whilst no co-infections with S. bovis were observed. This study has advanced our understanding of human and bovid schistosomiasis transmission in the Niger River Valley region. Human Schistosoma species/forms (S. haematobium and S. haematobium hybrids) were found transmitted only in five villages whereas those causing veterinary schistosomiasis (S. bovis), were found in most villages. Bulinus truncatus was most abundant, transmitting all Schistosoma species, while the less abundant B. forskalii and B. globosus, only transmitted S. bovis. Our data suggest that species-specific biological traits may exist in relation to co-infections, snail-schistosome compatibility and intramolluscan schistosome development.
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molecular characterization and distribution of Schistosoma cercariae collected from naturally infected bulinid snails in northern and central cote d ivoire
Parasites & Vectors, 2019Co-Authors: Yvesnathan T Tianbi, Bonnie L Webster, Cyrille K. Konan, Fiona Allan, Nana R. Diakité, Mamadou Ouattara, Diabaté Salia, Amani Koné, Adolphe K. Kakou, Muriel RaboneAbstract:Background Accurate identification of schistosome species infecting intermediate host snails is important for understanding parasite transmission, schistosomiasis control and elimination. Cercariae emerging from infected snails cannot be precisely identified morphologically to the species level. We used molecular tools to clarify the distribution of the Schistosoma haematobium group species infecting bulinid snails in a large part of Cote d’Ivoire and confirmed the presence of interspecific hybrid schistosomes.
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population genetic structure of Schistosoma mansoni and Schistosoma haematobium from across six sub saharan african countries implications for epidemiology evolution and control
Acta Tropica, 2013Co-Authors: Charlotte M Gower, Anouk N Gouvras, Poppy H L Lamberton, Arminder K Deol, Jaya Shrivastava, Polydor N Mutombo, Judith V Mbuh, Alice Norton, Bonnie L WebsterAbstract:We conducted the first meta-analysis of ten Schistosoma haematobium (one published and nine unpublished) and eight Schistosoma mansoni (two published and six unpublished) microsatellite datasets collected from individual schistosome-infected school-children across six sub-Saharan Africa countries. High levels of genetic diversity were documented in both S. haematobium and S. mansoni. In S. haematobium populations, allelic richness did not differ significantly between the ten schools, despite widely varying prevalences and intensities of infection, but higher levels of heterozygote deficiency were seen in East than in West Africa. In contrast, S. mansoni populations were more diverse in East than West African schools, but heterozygosity levels did not vary significantly with geography. Genetic structure in both S. haematobium and S. mansoni populations was documented, at both a regional and continental scale. Such structuring might be expected to slow the spread to new areas of anti-Schistosomal drug resistance should it develop. There was, however, limited evidence of genetic structure at the individual host level, which might be predicted to promote the development or establishment of drug resistance, particularly if it were a recessive trait. Our results are discussed in terms of their potential implications for the epidemiology and evolution of schistosomes as well as their subsequent control across sub-Saharan Africa.
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mitochondrial gene order change in Schistosoma platyhelminthes digenea Schistosomatidae
International Journal for Parasitology, 2012Co-Authors: Bonnie L WebsterAbstract:Abstract In the flatworm genus Schistosoma , species of which include parasites of biomedical and veterinary importance, mitochondrial gene order is radically different in some species. A PCR-based survey of 19 Schistosomatid spp. established which of 14 Schistosoma spp. have the ancestral (plesiomorphic) or derived gene order condition. A phylogeny for Schistosoma was estimated and used to infer the origin of the gene order change which is present in all members of a clade containing Schistosoma incognitum and members of the traditionally recognised Schistosoma indicum , Schistosoma mansoni and Schistosoma haematobium spp. groups. Schistosoma turkestanicum , with the plesiomorphic gene order state, is sister to this clade. Common interval analysis suggests change in gene order, from ancestral to derived, consisted of two sequential transposition events: (a) nad1 _ nad3 to nad3 _ nad1 and (b) [ atp6 , nad2 ]_[ nad3 , nad1 , cox1 , rrnL , rrnS , cox2 , nad6 ] to [ nad3 , nad1 , cox1 , rrnL , rrnS , cox2 , nad6 ]_[ atp6 , nad2 ], where gene order of fragments within square brackets remain unchanged. Gene order change is rare in parasitic flatworms and is a robust synapomorphy for schistosome spp. that exhibit it. The Schistosomatid phylogeny casts some doubt on the origin of Schistosoma (Asian or African), highlights the propensity for species to host switch amongst mammalian (definitive) hosts, and indicates the likely importance of snail (intermediate) hosts in determining and defining patterns of schistosome radiation and continental invasion. Mitogenomic sampling of Schistosoma dattai and Schistosoma harinasutai to determine gene order, and within key species, especially S. turkestanicum and S. incognitum , to determine ancestral ranges, may help discover the geographic origins of gene order change in the genus. Samples of S. incognitum from India and Thailand suggest this taxon may include cryptic species.
Karl F Hoffmann - One of the best experts on this subject based on the ideXlab platform.
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Development and validation of a quantitative, high-throughput, fluorescent-based bioassay to detect Schistosoma viability.
Public Library of Science (PLoS), 2010Co-Authors: Emily Peak, Iain W. Chalmers, Karl F HoffmannAbstract:Schistosomiasis, caused by infection with the blood fluke Schistosoma, is responsible for greater than 200,000 human deaths per annum. Objective high-throughput screens for detecting novel anti-Schistosomal targets will drive 'genome to drug' lead translational science at an unprecedented rate. Current methods for detecting schistosome viability rely on qualitative microscopic criteria, which require an understanding of parasite morphology, and most importantly, must be subjectively interpreted. These limitations, in the current state of the art, have significantly impeded progress into whole schistosome screening for next generation chemotherapies.We present here a microtiter plate-based method for reproducibly detecting schistosomula viability that takes advantage of the differential uptake of fluorophores (propidium iodide and fluorescein diacetate) by living organisms. We validate this high-throughput system in detecting schistosomula viability using auranofin (a known inhibitor of thioredoxin glutathione reductase), praziquantel and a range of small compounds with previously-described (gambogic acid, sodium salinomycin, ethinyl estradiol, fluoxetidine hydrochloride, miconazole nitrate, chlorpromazine hydrochloride, amphotericin b, niclosamide) or suggested (bepridil, ciclopirox, rescinnamine, flucytosine, vinblastine and carbidopa) anti-Schistosomal activities. This developed method is sensitive (200 schistosomula/well can be assayed), relevant to industrial (384-well microtiter plate compatibility) and academic (96-well microtiter plate compatibility) settings, translatable to functional genomics screens and drug assays, does not require a priori knowledge of schistosome biology and is quantitative.The wide-scale application of this fluorescence-based bioassay will greatly accelerate the objective identification of novel therapeutic lead targets/compounds to combat schistosomiasis. Adapting this bioassay for use with other parasitic worm species further offers an opportunity for great strides to be made against additional neglected tropical diseases of biomedical and veterinary importance
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Development and validation of a quantitative, high-throughput, fluorescent-based bioassay to detect Schistosoma viability. PLoS Negl. Trop. Dis
2010Co-Authors: Emily Peak, Iain W. Chalmers, Karl F HoffmannAbstract:Background: Schistosomiasis, caused by infection with the blood fluke Schistosoma, is responsible for greater than 200,000 human deaths per annum. Objective high-throughput screens for detecting novel anti-Schistosomal targets will drive ‘genome to drug ’ lead translational science at an unprecedented rate. Current methods for detecting schistosome viability rely on qualitative microscopic criteria, which require an understanding of parasite morphology, and most importantly, must be subjectively interpreted. These limitations, in the current state of the art, have significantly impeded progress into whole schistosome screening for next generation chemotherapies. Methodology/Principal Findings: We present here a microtiter plate-based method for reproducibly detecting schistosomula viability that takes advantage of the differential uptake of fluorophores (propidium iodide and fluorescein diacetate) by living organisms. We validate this high-throughput system in detecting schistosomula viability using auranofin (a known inhibitor of thioredoxin glutathione reductase), praziquantel and a range of small compounds with previouslydescribed (gambogic acid, sodium salinomycin, ethinyl estradiol, fluoxetidine hydrochloride, miconazole nitrate, chlorpromazine hydrochloride, amphotericin b, niclosamide) or suggested (bepridil, ciclopirox, rescinnamine, flucytosine, vinblastine and carbidopa) anti-Schistosomal activities. This developed method is sensitive (200 schistosomula/well can be assayed), relevant to industrial (384-well microtiter plate compatibility) and academic (96-well microtiter plate compatibility
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biomphalaria glabrata transcriptome cdna microarray profiling identifies resistant and susceptible specific gene expression in haemocytes from snail strains exposed to Schistosoma mansoni
BMC Genomics, 2008Co-Authors: Anne E Lockyer, David Rollinson, Jenny Spinks, Richard A Kane, Karl F Hoffmann, Jennifer M Fitzpatrick, Leslie R Noble, Catherine S JonesAbstract:Background Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. B. glabrata/S. mansoni provides a useful model system for investigating the intimate interactions between host and parasite. Examining differential gene expression between S. mansoni-exposed schistosome-resistant and susceptible snail lines will identify genes and pathways that may be involved in snail defences.
Andreas Ruppel - One of the best experts on this subject based on the ideXlab platform.
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invasion by schistosome cercariae neglected aspects in Schistosoma japonicum
Trends in Parasitology, 2004Co-Authors: Andreas Ruppel, Katerina Chlichlia, Mahmoud M BahgatAbstract:Skin invasion by schistosome cercariae was recently discussed in Trends in Parasitology. However, only Schistosoma mansoni was considered, possibly because this species predominates in laboratory studies (at least outside China). One may be tempted to extrapolate from the ‘model’ S. mansoni to other schistosomes, but Schistosoma japonicum must not be neglected. This schistosome is distinguishable from others (particularly S. mansoni) by virtue of its remarkable speed and success of migration, as well as by specific biochemical and immunological features. This leads to the hypothesis that S. japonicum is atypical with respect to the enzymes that facilitate skin penetration.
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polymerase chain reaction assay based on a highly repeated sequence of Schistosoma haematobium a potential tool for monitoring schistosome infested water
American Journal of Tropical Medicine and Hygiene, 2001Co-Authors: Joseph Hamburger, Reda M R Ramzy, J Jourdane, Ibrahim Abbasi, Andreas RuppelAbstract:We have cloned from Schistosoma haematobium genome a repeated sequence, the DraI repeated sequence, which consists of tandemly arranged 121-bp-long units and which is highly abundant (approximately 15% of the S. haematobium genome). By these features, the DraI repeat is similar to the Sm1-7 sequence of Schistosoma mansoni previously described by us. However, their nucleotide sequences are profoundly different. Polymerase chain reaction (PCR) primers were designed on the basis of the DraI sequence information and were used in a PCR assay by which as little as 10 fg of Schistosomal DNA as well as individual cercariae were detected. The DraI repeat cross-hybridized with DNA from Schistosoma bovis, Schistosoma magrebowiei, Schistosoma mattheei, Schistosoma curassoni, and Schistosoma intercalatum, but not with DNA from S. mansoni nor from Trichobilharzia ocellata and Echinostoma sp. A potential value of this PCR assay is suggested for monitoring free-living cercariae and infected snails only in bodies free of cross-hybridizing species.
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Polymerase chain reaction assay based on a highly repeated sequence of Schistosoma haematobium: a potential tool for monitoring schistosome-infested water. Am J Trop Med Hyg 65: 907−911
2001Co-Authors: Joseph Hamburger, Reda M R Ramzy, J Jourdane, Ibrahim Abbasi, Andreas RuppelAbstract:Abstract. We have cloned from Schistosoma haematobium genome a repeated sequence, the DraI repeated se-quence, which consists of tandemly arranged 121-bp-long units and which is highly abundant ( 15 % of the S. haematobium genome). By these features, the DraI repeat is similar to the Sm1–7 sequence of Schistosoma mansoni previously described by us. However, their nucleotide sequences are profoundly different. Polymerase chain reaction (PCR) primers were designed on the basis of the DraI sequence information and were used in a PCR assay by which as little as 10 fg of Schistosomal DNA as well as individual cercariae were detected. The DraI repeat cross-hybridized with DNA from Schistosoma bovis, Schistosoma magrebowiei, Schistosoma mattheei, Schistosoma curassoni, and Schistosoma intercalatum, but not with DNA from S. mansoni nor from Trichobilharzia ocellata and Echinostoma sp. A potential value of this PCR assay is suggested for monitoring free-living cercariae and infected snails only in bodies free of cross-hybridizing species
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circulating antigens in schistosomiasis detection of 31 32 kda proteins in sera from patients infected with Schistosoma japonicum s mansoni s haematobium or s intercalatum
Parasitology Research, 1996Co-Authors: M A Idris, M Corachan, J J Han, Michael Kirschfink, Andreas RuppelAbstract:A sandwich enzyme-linked immunosorbent assay (ELISA) was developed to detect 31/32-kDa schistosome proteins as circulating antigens in sera from schistosomiasis patients. A monoclonal antibody was used as a capture antibody and rabbit antiserum raised against purified 31/32-kDa proteins was the detecting antibody. Positive results were obtained with patients infected with Schistosoma japonicum (88%; n=69), S. mansoni (80%; n=56), S. haematobium (100%; n=40), or S. intercalatum (94%; n=65). Sera from uninfected Chinese and African individuals and from Chinese patients with trichinosis, cysticercosis, or paragonimiasis did not react in the assay. This ELISA appears to be valuable in diagnosing infections by all major human schistosome species.
Muriel Rabone - One of the best experts on this subject based on the ideXlab platform.
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Interactions between Schistosoma haematobium group species and their Bulinus spp. intermediate hosts along the Niger River Valley.
Parasites & vectors, 2020Co-Authors: Tom Pennance, Aidan M. Emery, David Rollinson, Fiona Allan, Muriel Rabone, Jo Cable, Amadou Garba, Amina Amadou Hamidou, Joanne P. Webster, Bonnie L WebsterAbstract:Urogenital schistosomiasis, caused by infection with Schistosoma haematobium, is endemic in Niger but complicated by the presence of Schistosoma bovis, Schistosoma curassoni and S. haematobium group hybrids along with various Bulinus snail intermediate host species. Establishing the schistosomes and snails involved in transmission aids disease surveillance whilst providing insights into snail-schistosome interactions/compatibilities and biology. Infected Bulinus spp. were collected from 16 villages north and south of the Niamey region, Niger, between 2011 and 2015. From each Bulinus spp., 20–52 cercariae shed were analysed using microsatellite markers and a subset identified using the mitochondrial (mt) cox1 and nuclear ITS1 + 2 and 18S DNA regions. Infected Bulinus spp. were identified using both morphological and molecular analysis (partial mt cox1 region). A total of 87 infected Bulinus from 24 sites were found, 29 were molecularly confirmed as B. truncatus, three as B. forskalii and four as B. globosus. The remaining samples were morphologically identified as B. truncatus (n = 49) and B. forskalii (n = 2). The microsatellite analysis of 1124 cercariae revealed 186 cercarial multilocus genotypes (MLGs). Identical cercarial genotypes were frequently (60%) identified from the same snail (clonal populations from a single miracidia); however, several (40%) of the snails had cercariae of different genotypes (2–10 MLG’s) indicating multiple miracidial infections. Fifty-seven of the B. truncatus and all of the B. forskalii and B. globosus were shedding the Bovid schistosome S. bovis. The other B. truncatus were shedding the human schistosomes, S. haematobium (n = 6) and the S. haematobium group hybrids (n = 13). Two B. truncatus had co-infections with S. haematobium and S. haematobium group hybrids whilst no co-infections with S. bovis were observed. This study has advanced our understanding of human and bovid schistosomiasis transmission in the Niger River Valley region. Human Schistosoma species/forms (S. haematobium and S. haematobium hybrids) were found transmitted only in five villages whereas those causing veterinary schistosomiasis (S. bovis), were found in most villages. Bulinus truncatus was most abundant, transmitting all Schistosoma species, while the less abundant B. forskalii and B. globosus, only transmitted S. bovis. Our data suggest that species-specific biological traits may exist in relation to co-infections, snail-schistosome compatibility and intramolluscan schistosome development.
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Molecular characterization and distribution of Schistosoma cercariae collected from naturally infected bulinid snails in northern and central Côte d’Ivoire
Parasites & Vectors, 2019Co-Authors: Yves-nathan T. Tian-bi, Bonnie Webster, Cyrille K. Konan, Fiona Allan, Nana R. Diakité, Mamadou Ouattara, Diabaté Salia, Amani Koné, Adolphe K. Kakou, Muriel RaboneAbstract:Background Accurate identification of schistosome species infecting intermediate host snails is important for understanding parasite transmission, schistosomiasis control and elimination. Cercariae emerging from infected snails cannot be precisely identified morphologically to the species level. We used molecular tools to clarify the distribution of the Schistosoma haematobium group species infecting bulinid snails in a large part of Côte d’Ivoire and confirmed the presence of interspecific hybrid schistosomes. Methods Between June 2016 and March 2017, Bulinus snails were sampled in 164 human-water contact sites from 22 villages of the northern and central parts of Côte d’Ivoire. Multi-locus genetic analysis (mitochondrial cox 1 and nuclear ITS) was performed on individual schistosome cercariae shed from snails, in the morning and in the afternoon, for species and hybrid identification. Results Overall, 1923 Bulinus truncatus , 255 Bulinus globosus and 1424 Bulinus forskalii were obtained. Among 2417 Bulinus screened, 25 specimens (18 B. truncatus and seven B. globosus ) shed schistosomes, with up to 14% infection prevalence per site and time point. Globally, infection rates per time point ranged between 0.6 and 4%. Schistosoma bovis , S. haematobium and S. bovis × S. haematobium hybrids infected 0.5%, 0.2% and 0.4% of the snails screened, respectively. Schistosoma bovis and hybrids were more prevalent in B. truncatus , whereas S. haematobium and hybrid infections were more prevalent in B. globosus . Schistosoma bovis -infected Bulinus were predominantly found in northern sites, while S. haematobium and hybrid infected snails were mainly found in central parts of Côte d’Ivoire. Conclusions The data highlight the necessity of using molecular tools to identify and understand which schistosome species are transmitted by specific intermediate host snails. The study deepens our understanding of the epidemiology and transmission dynamics of S. haematobium and S. bovis in Côte d’Ivoire and provides the first conclusive evidence for the transmission of S. haematobium × S. bovis hybrids in this West African country. Trial registration ISRCTN, ISRCTN10926858. Registered 21 December 2016; retrospectively registered (see: http://www.isrctn.com/ISRCTN10926858 )
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molecular characterization and distribution of Schistosoma cercariae collected from naturally infected bulinid snails in northern and central cote d ivoire
Parasites & Vectors, 2019Co-Authors: Yvesnathan T Tianbi, Bonnie L Webster, Cyrille K. Konan, Fiona Allan, Nana R. Diakité, Mamadou Ouattara, Diabaté Salia, Amani Koné, Adolphe K. Kakou, Muriel RaboneAbstract:Background Accurate identification of schistosome species infecting intermediate host snails is important for understanding parasite transmission, schistosomiasis control and elimination. Cercariae emerging from infected snails cannot be precisely identified morphologically to the species level. We used molecular tools to clarify the distribution of the Schistosoma haematobium group species infecting bulinid snails in a large part of Cote d’Ivoire and confirmed the presence of interspecific hybrid schistosomes.
Fiona Allan - One of the best experts on this subject based on the ideXlab platform.
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Interactions between Schistosoma haematobium group species and their Bulinus spp. intermediate hosts along the Niger River Valley.
Parasites & vectors, 2020Co-Authors: Tom Pennance, Aidan M. Emery, David Rollinson, Fiona Allan, Muriel Rabone, Jo Cable, Amadou Garba, Amina Amadou Hamidou, Joanne P. Webster, Bonnie L WebsterAbstract:Urogenital schistosomiasis, caused by infection with Schistosoma haematobium, is endemic in Niger but complicated by the presence of Schistosoma bovis, Schistosoma curassoni and S. haematobium group hybrids along with various Bulinus snail intermediate host species. Establishing the schistosomes and snails involved in transmission aids disease surveillance whilst providing insights into snail-schistosome interactions/compatibilities and biology. Infected Bulinus spp. were collected from 16 villages north and south of the Niamey region, Niger, between 2011 and 2015. From each Bulinus spp., 20–52 cercariae shed were analysed using microsatellite markers and a subset identified using the mitochondrial (mt) cox1 and nuclear ITS1 + 2 and 18S DNA regions. Infected Bulinus spp. were identified using both morphological and molecular analysis (partial mt cox1 region). A total of 87 infected Bulinus from 24 sites were found, 29 were molecularly confirmed as B. truncatus, three as B. forskalii and four as B. globosus. The remaining samples were morphologically identified as B. truncatus (n = 49) and B. forskalii (n = 2). The microsatellite analysis of 1124 cercariae revealed 186 cercarial multilocus genotypes (MLGs). Identical cercarial genotypes were frequently (60%) identified from the same snail (clonal populations from a single miracidia); however, several (40%) of the snails had cercariae of different genotypes (2–10 MLG’s) indicating multiple miracidial infections. Fifty-seven of the B. truncatus and all of the B. forskalii and B. globosus were shedding the Bovid schistosome S. bovis. The other B. truncatus were shedding the human schistosomes, S. haematobium (n = 6) and the S. haematobium group hybrids (n = 13). Two B. truncatus had co-infections with S. haematobium and S. haematobium group hybrids whilst no co-infections with S. bovis were observed. This study has advanced our understanding of human and bovid schistosomiasis transmission in the Niger River Valley region. Human Schistosoma species/forms (S. haematobium and S. haematobium hybrids) were found transmitted only in five villages whereas those causing veterinary schistosomiasis (S. bovis), were found in most villages. Bulinus truncatus was most abundant, transmitting all Schistosoma species, while the less abundant B. forskalii and B. globosus, only transmitted S. bovis. Our data suggest that species-specific biological traits may exist in relation to co-infections, snail-schistosome compatibility and intramolluscan schistosome development.
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Molecular characterization and distribution of Schistosoma cercariae collected from naturally infected bulinid snails in northern and central Côte d’Ivoire
Parasites & Vectors, 2019Co-Authors: Yves-nathan T. Tian-bi, Bonnie Webster, Cyrille K. Konan, Fiona Allan, Nana R. Diakité, Mamadou Ouattara, Diabaté Salia, Amani Koné, Adolphe K. Kakou, Muriel RaboneAbstract:Background Accurate identification of schistosome species infecting intermediate host snails is important for understanding parasite transmission, schistosomiasis control and elimination. Cercariae emerging from infected snails cannot be precisely identified morphologically to the species level. We used molecular tools to clarify the distribution of the Schistosoma haematobium group species infecting bulinid snails in a large part of Côte d’Ivoire and confirmed the presence of interspecific hybrid schistosomes. Methods Between June 2016 and March 2017, Bulinus snails were sampled in 164 human-water contact sites from 22 villages of the northern and central parts of Côte d’Ivoire. Multi-locus genetic analysis (mitochondrial cox 1 and nuclear ITS) was performed on individual schistosome cercariae shed from snails, in the morning and in the afternoon, for species and hybrid identification. Results Overall, 1923 Bulinus truncatus , 255 Bulinus globosus and 1424 Bulinus forskalii were obtained. Among 2417 Bulinus screened, 25 specimens (18 B. truncatus and seven B. globosus ) shed schistosomes, with up to 14% infection prevalence per site and time point. Globally, infection rates per time point ranged between 0.6 and 4%. Schistosoma bovis , S. haematobium and S. bovis × S. haematobium hybrids infected 0.5%, 0.2% and 0.4% of the snails screened, respectively. Schistosoma bovis and hybrids were more prevalent in B. truncatus , whereas S. haematobium and hybrid infections were more prevalent in B. globosus . Schistosoma bovis -infected Bulinus were predominantly found in northern sites, while S. haematobium and hybrid infected snails were mainly found in central parts of Côte d’Ivoire. Conclusions The data highlight the necessity of using molecular tools to identify and understand which schistosome species are transmitted by specific intermediate host snails. The study deepens our understanding of the epidemiology and transmission dynamics of S. haematobium and S. bovis in Côte d’Ivoire and provides the first conclusive evidence for the transmission of S. haematobium × S. bovis hybrids in this West African country. Trial registration ISRCTN, ISRCTN10926858. Registered 21 December 2016; retrospectively registered (see: http://www.isrctn.com/ISRCTN10926858 )
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molecular characterization and distribution of Schistosoma cercariae collected from naturally infected bulinid snails in northern and central cote d ivoire
Parasites & Vectors, 2019Co-Authors: Yvesnathan T Tianbi, Bonnie L Webster, Cyrille K. Konan, Fiona Allan, Nana R. Diakité, Mamadou Ouattara, Diabaté Salia, Amani Koné, Adolphe K. Kakou, Muriel RaboneAbstract:Background Accurate identification of schistosome species infecting intermediate host snails is important for understanding parasite transmission, schistosomiasis control and elimination. Cercariae emerging from infected snails cannot be precisely identified morphologically to the species level. We used molecular tools to clarify the distribution of the Schistosoma haematobium group species infecting bulinid snails in a large part of Cote d’Ivoire and confirmed the presence of interspecific hybrid schistosomes.
