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Maes T, De Corte Z, Vangestel C, Virgilio M, Smitz N, Djuikwo-Teukeng FF, Papadaki MI, Huyse T. Large-scale and small-scale population genetic structure of the medically important gastropod species Bulinus truncatus (Gastropoda, Heterobranchia). Parasit Vectors 2022; 15:328. [PMID: 36123605 PMCID: PMC9484234 DOI: 10.1186/s13071-022-05445-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/12/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Gastropod snails remain strongly understudied, despite their important role in transmitting parasitic diseases. Knowledge of their distribution and population dynamics increases our understanding of the processes driving disease transmission. We report the first study to use high-throughput sequencing (HTS) to elucidate the population genetic structure of the hermaphroditic snail Bulinus truncatus (Gastropoda, Heterobranchia) on a regional (17-150 km) and inter-regional (1000-5400 km) scale. This snail species acts as an intermediate host of Schistosoma haematobium and Schistosoma bovis, which cause human and animal schistosomiasis respectively. METHODS Bulinus truncatus snails were collected in Senegal, Cameroon, Egypt and France and identified through DNA barcoding. A single-end genotyping-by-sequencing (GBS) library, comprising 87 snail specimens from the respective countries, was built and sequenced on an Illumina HiSeq 2000 platform. Reads were mapped against S. bovis and S. haematobium reference genomes to identify schistosome infections, and single nucleotide polymorphisms (SNPs) were scored using the Stacks pipeline. These SNPs were used to estimate genetic diversity, assess population structure and construct phylogenetic trees of B. truncatus. RESULTS A total of 10,750 SNPs were scored and used in downstream analyses. The phylogenetic analysis identified five clades, each consisting of snails from a single country but with two distinct clades within Senegal. Genetic diversity was low in all populations, reflecting high selfing rates, but varied between locations due to habitat variability. Significant genetic differentiation and isolation by distance patterns were observed at both spatial scales, indicating that gene flow is not strong enough to counteract the effects of population bottlenecks, high selfing rates and genetic drift. Remarkably, the population genetic differentiation on a regional scale (i.e. within Senegal) was as large as that between populations on an inter-regional scale. The blind GBS technique was able to pick up parasite DNA in snail tissue, demonstrating the potential of HTS techniques to further elucidate the role of snail species in parasite transmission. CONCLUSIONS HTS techniques offer a valuable toolbox to further investigate the population genetic patterns of intermediate schistosome host snails and the role of snail species in parasite transmission.
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Affiliation(s)
- Tim Maes
- Department of Biology, Katholieke Universiteit Leuven, Ch. Deberiotstraat 32, 3000 Leuven, Belgium
- Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
| | - Zoë De Corte
- Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
- Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
| | - Carl Vangestel
- Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
- Terrestrial Ecology Unit, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | | | - Nathalie Smitz
- Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
| | | | - Maria Ioanna Papadaki
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Katholieke Universiteit Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Tine Huyse
- Department of Biology, Katholieke Universiteit Leuven, Ch. Deberiotstraat 32, 3000 Leuven, Belgium
- Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium
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Tumwebaze I, Clewing C, Dusabe MC, Tumusiime J, Kagoro-Rugunda G, Hammoud C, Albrecht C. Molecular identification of Bulinus spp. intermediate host snails of Schistosoma spp. in crater lakes of western Uganda with implications for the transmission of the Schistosoma haematobium group parasites. Parasit Vectors 2019; 12:565. [PMID: 31775865 PMCID: PMC6882369 DOI: 10.1186/s13071-019-3811-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 11/15/2019] [Indexed: 12/05/2022] Open
Abstract
Background Human schistosomiasis is the second most important tropical disease and occurs in two forms in Africa (intestinal and urogenital) caused by the digenetic trematodes Schistosoma mansoni and Schistosoma haematobium, respectively. A proposed recent shift of schistosomiasis above a previously established altitudinal threshold of 1400 m above sea level in western Ugandan crater lakes has triggered more research interest there. Methods Based on extensive field sampling in western Uganda and beyond and employing an approach using sequences of the mitochondrial barcoding gene cytochrome c oxidase subunit 1 (cox1) this study aims were: (i) identification and establishment of the phylogenetic affinities of Bulinus species as potential hosts for Schistosoma spp.; (ii) determining diversity, frequency and distribution patterns of Bulinus spp.; and (iii) establishing genetic variability and phylogeographical patterns using Bayesian inference and parsimony network analyses. Results Out of the 58 crater lakes surveyed, three species of Bulinus snails were found in 34 crater lakes. Bulinus tropicus was dominating, Bulinus forskalii was found in two lakes and Bulinus truncatus in one. The latter two species are unconfirmed potential hosts for S. haematobium in this region. However, Bulinus tropicus is an important species for schistosomiasis transmission in ruminants. Bulinus tropicus comprised 31 haplotypes while both B. forskalii and B. truncatus exhibited only a single haplotype in the crater lakes. All species clustered with most of the haplotypes from surrounding lake systems forming source regions for the colonization of the crater lakes. Conclusions This first detailed malacological study of the crater lakes systems in western Uganda revealed presence of Bulinus species that are either not known or not regionally known to be hosts for S. haematobium, the causing agent of human urogenital schistosomiasis. Though this disease risk is almost negligible, the observed dominance of B. tropicus in the crater lakes shows that there is a likelihood of a high risk of infections with Schistosoma bovis. Thus, extra attention should be accorded to safeguard wild and domestic ruminants in this region as the population benefits from these animals.
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Affiliation(s)
- Immaculate Tumwebaze
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany.
| | - Catharina Clewing
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
| | | | - Julius Tumusiime
- Department of Biology, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Grace Kagoro-Rugunda
- Department of Biology, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Cyril Hammoud
- Department of Biology, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080, Tervuren, Belgium.,Limnology Research Unit, Ghent University, K. L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Christian Albrecht
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany.,Department of Biology, Mbarara University of Science and Technology, Mbarara, Uganda
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Gauffre-Autelin P, von Rintelen T, Stelbrink B, Albrecht C. Recent range expansion of an intermediate host for animal schistosome parasites in the Indo-Australian Archipelago: phylogeography of the freshwater gastropod Indoplanorbis exustus in South and Southeast Asia. Parasit Vectors 2017; 10:126. [PMID: 28264699 PMCID: PMC5339995 DOI: 10.1186/s13071-017-2043-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 02/17/2017] [Indexed: 03/13/2024] Open
Abstract
Background The planorbid snail Indoplanorbis exustus is the sole intermediate host for the Schistosoma indicum species group, trematode parasites responsible for cattle schistosomiasis and human cercarial dermatitis. This freshwater snail is widely distributed in Southern Asia, ranging from Iran to China eastwards including India and from the southeastern Himalayas to Southeast Asia southwards. The veterinary and medical importance of this snail explains the interest in understanding its geographical distribution patterns and evolutionary history. In this study, we used a large and comprehensive sampling throughout Indo-Malaya, including specimens from South India and Indonesia, areas that have been formerly less studied. Results The phylogenetic inference revealed five highly divergent clades (genetic distances among clades: 4.4–13.9%) that are morphologically indistinguishable, supporting the assumption that this presumed nominal species may represent a cryptic species complex. The species group may have originated in the humid subtropical plains of Nepal or in southern adjacent regions in the Early Miocene. The major cladogenetic events leading to the fives clades occurred successively from the Early Miocene to the Early Pleistocene, coinciding with major periods of monsoonal intensification associated with major regional paleogeographic events in the Miocene and repeated climate changes due to the Plio-Pleistocene climatic oscillations. Our coverage of the Indo-Australian Archipelago (IAA) highlights the presence of a single clade there. Contrary to expectations, an AMOVA did not reveal any population genetic structure among islands or along a widely recognised zoogeographical regional barrier, suggesting a recent colonisation independent of natural biogeographical constraints. Neutrality tests and mismatch distributions suggested a sudden demographic and spatial population expansion that could have occurred naturally in the Pleistocene or may possibly result of a modern colonisation triggered by anthropogenic activities. Conclusions Even though Indoplanorbis is the main focus of this study, our findings may also have important implications for fully understanding its role in hosting digenetic trematodes. The existence of a cryptic species complex, the historical phylogeographical patterns and the recent range expansion in the IAA provide meaningful insights to the understanding and monitoring of the parasites potential spread. It brings a substantial contribution to veterinary and public health issues. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2043-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Thomas von Rintelen
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Björn Stelbrink
- Department of Animal Ecology and Systematics, Justus Liebig University, Giessen, Germany
| | - Christian Albrecht
- Department of Animal Ecology and Systematics, Justus Liebig University, Giessen, Germany
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Giannelli A, Cantacessi C, Colella V, Dantas-Torres F, Otranto D. Gastropod-Borne Helminths: A Look at the Snail-Parasite Interplay. Trends Parasitol 2015; 32:255-264. [PMID: 26740470 DOI: 10.1016/j.pt.2015.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/16/2015] [Accepted: 12/03/2015] [Indexed: 10/22/2022]
Abstract
More than 300 million people suffer from a range of diseases caused by gastropod-borne helminths, predominantly flatworms and roundworms, whose life cycles are characterized by a diversified ecology and epidemiology. Despite the plethora of data on these parasites, very little is known of the fundamental biology of their gastropod intermediate hosts, or of the interactions occurring at the snail-helminth interface. In this article, we focus on schistosomes and metastrongylids of human and animal significance, and review current knowledge of snail-parasite interplay. Future efforts aimed at elucidating key elements of the biology and ecology of the snail intermediate hosts, together with an improved understanding of snail-parasite interactions, will aid to identify, plan, and develop new strategies for disease control focused on gastropod intermediate hosts.
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Affiliation(s)
- Alessio Giannelli
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano 70010, Italy
| | - Cinzia Cantacessi
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Vito Colella
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano 70010, Italy
| | - Filipe Dantas-Torres
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano 70010, Italy; Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães (Fiocruz-PE), Recife, Pernambuco, Brazil
| | - Domenico Otranto
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano 70010, Italy.
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Lawton SP, Lim RM, Dukes JP, Kett SM, Cook RT, Walker AJ, Kirk RS. Unravelling the riddle of Radix: DNA barcoding for species identification of freshwater snail intermediate hosts of zoonotic digeneans and estimating their inter-population evolutionary relationships. INFECTION GENETICS AND EVOLUTION 2015. [PMID: 26196736 DOI: 10.1016/j.meegid.2015.07.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Radix spp. are intermediate host snails for digenean parasites of medical and veterinary importance. Within this genus, species differentiation using shell and internal organ morphology can result in erroneous species identification, causing problems when trying to understand the population biology of Radix. In the present study, DNA barcoding, using cox1 and ITS2 sequences, identified populations of Radix auricularia and Radix balthica from specimens originally morphologically identified as Radix peregra from the UK. Assessment of cox1 and ITS2 as species identification markers showed that, although both markers differentiated species, cox1 possessed greater molecular diversity and higher phylogenetic resolution. Cox1 also proved useful for gaining insights into the evolutionary relationships of Radix species populations. Phylogenetic analysis and haplotype networks of cox1 indicated that R. auricularia appeared to have invaded the UK several times; some haplotypes forming a distinct UK specific clade, whilst others are more akin to those found on mainland Europe. This was in contrast to relationships between R. balthica populations, which had low molecular diversity and no distinct UK specific haplotypes, suggesting recent and multiple invasions from mainland Europe. Molecular techniques therefore appear to be crucial for distinguishing Radix spp., particularly using cox1. This barcoding marker also enables the population biology of Radix spp. to be explored, and is invaluable for monitoring the epidemiology of fluke diseases especially in the light of emerging diseases and food security.
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Affiliation(s)
- Scott P Lawton
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK.
| | - Rivka M Lim
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK
| | - Juliet P Dukes
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK
| | - Stephen M Kett
- School of Life Sciences, Middlesex University, The Burroughs, London NW4 4BT, UK.
| | - Richard T Cook
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK.
| | - Anthony J Walker
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK.
| | - Ruth S Kirk
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK.
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Akinwale O, Oso O, Salawu O, Odaibo A, Tang P, Chen TW, Gyang P. Molecular characterisation of Bulinus snails – intermediate hosts of schistosomes in Ogun State, South-western Nigeria. FOLIA MALACOLOGICA 2015. [DOI: 10.12657/folmal.023.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Makaula P, Sadalaki JR, Muula AS, Kayuni S, Jemu S, Bloch P. Schistosomiasis in Malawi: a systematic review. Parasit Vectors 2014; 7:570. [PMID: 25490938 PMCID: PMC4288699 DOI: 10.1186/s13071-014-0570-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/25/2014] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Schistosomiasis remains an important public health problem that undermines social and economic development in tropical regions of the world, mainly Sub-Saharan Africa. We are not aware of any systematic review of the literature of the epidemiology and transmission of schistosomiasis in Malawi since 1985. Therefore, we reviewed the current state of knowledge of schistosomiasis epidemiology and transmission in this country and identified knowledge gaps and relevant areas for future research and research governance. METHODS We conducted computer-aided literature searches of Medline, SCOPUS and Google Scholar using the keywords: "schistosomiasis", "Bilharzia", "Bulinus" and "Biomphalaria" in combination with "Malawi". These searches were supplemented by iterative reviews of reference lists for relevant publications in peer reviewed international scientific journals or other media. The recovered documents were reviewed for their year of publication, location of field or laboratory work, authorship characteristics, ethics review, funding sources as well as their findings regarding parasite and intermediate host species, environmental aspects, geographical distribution, seasonality of transmission, and infection prevalence and intensities. REVIEW A total of 89 documents satisfied the inclusion criteria and were reviewed. Of these, 76 were published in international scientific journals, 68 were peer reviewed and 54 were original research studies. Most of the documents addressed urinary schistosomiasis and about two thirds of them dealt with the definitive host. Few documents addressed the parasites and the intermediate hosts. While urinary schistosomiasis occurs in most parts of Malawi, intestinal schistosomiasis mainly occurs in the central and southern highlands, Likoma Island and Lower Shire. Studies in selected communities estimated prevalence rates of up to 94.9% for Schistosoma haematobium and up to 67.0% for Schistosoma mansoni with considerable geographical variation. The main intermediate host species are Bulinus globosus and Bulinus nyassanus for urinary schistosomiasis and Biomphalaria pfeifferi for intestinal schistosomiasis. Seasonality of transmission tends to vary according to geographical, environmental, biological and behavioural factors. CONCLUSION Transmission of schistosomiasis in Malawi appears to be highly focal, with considerable variation in space and time. Many locations have not been covered by epidemiological investigations and, thus, information on the transmission of schistosomiasis in Malawi remains fragmented. Functional infection risk assessment systems based on systematic investigations and surveillance are required for developing informed prevention and control strategies.
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Affiliation(s)
- Peter Makaula
- Research for Health Environment and Development, P.O. Box 345, Mangochi, Malawi.
| | - John R Sadalaki
- School of Public Health and Family Medicine, Department of Public Health, College of Medicine, University of Malawi, Private Bag 360, Chichiri, Blantyre 3, Malawi.
| | - Adamson S Muula
- School of Public Health and Family Medicine, Department of Public Health, College of Medicine, University of Malawi, Private Bag 360, Chichiri, Blantyre 3, Malawi.
| | - Sekeleghe Kayuni
- Medical Aid Society of Malawi (MASM) Medi Clinics, P.O. Box 1254, Blantyre, Malawi.
| | - Samuel Jemu
- Ministry of Health, P.O. Box 30377, Capital City, Lilongwe 3, Malawi.
| | - Paul Bloch
- Steno Health Promotion Center, Steno Diabetes Center, Niels Steensens Vej 8, DK-2820, Gentofte, Denmark.
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Stensgaard AS, Utzinger J, Vounatsou P, Hürlimann E, Schur N, Saarnak CF, Simoonga C, Mubita P, Kabatereine NB, Tchuem Tchuenté LA, Rahbek C, Kristensen TK. Large-scale determinants of intestinal schistosomiasis and intermediate host snail distribution across Africa: does climate matter? Acta Trop 2013; 128:378-90. [PMID: 22142789 DOI: 10.1016/j.actatropica.2011.11.010] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 11/15/2011] [Accepted: 11/18/2011] [Indexed: 10/15/2022]
Abstract
The geographical ranges of most species, including many infectious disease agents and their vectors and intermediate hosts, are assumed to be constrained by climatic tolerances, mainly temperature. It has been suggested that global warming will cause an expansion of the areas potentially suitable for infectious disease transmission. However, the transmission of infectious diseases is governed by a myriad of ecological, economic, evolutionary and social factors. Hence, a deeper understanding of the total disease system (pathogens, vectors and hosts) and its drivers is important for predicting responses to climate change. Here, we combine a growing degree day model for Schistosoma mansoni with species distribution models for the intermediate host snail (Biomphalaria spp.) to investigate large-scale environmental determinants of the distribution of the African S. mansoni-Biomphalaria system and potential impacts of climatic changes. Snail species distribution models included several combinations of climatic and habitat-related predictors; the latter divided into "natural" and "human-impacted" habitat variables to measure anthropogenic influence. The predictive performance of the combined snail-parasite model was evaluated against a comprehensive compilation of historical S. mansoni parasitological survey records, and then examined for two climate change scenarios of increasing severity for 2080. Future projections indicate that while the potential S. mansoni transmission area expands, the snail ranges are more likely to contract and/or move into cooler areas in the south and east. Importantly, we also note that even though climate per se matters, the impact of humans on habitat play a crucial role in determining the distribution of the intermediate host snails in Africa. Thus, a future contraction in the geographical range size of the intermediate host snails caused by climatic changes does not necessarily translate into a decrease or zero-sum change in human schistosomiasis prevalence.
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Jørgensen A, Stothard JR, Madsen H, Nalugwa A, Nyakaana S, Rollinson D. The ITS2 of the genus Bulinus: novel secondary structure among freshwater snails and potential new taxonomic markers. Acta Trop 2013; 128:218-25. [PMID: 22677601 DOI: 10.1016/j.actatropica.2012.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 05/15/2012] [Accepted: 05/20/2012] [Indexed: 11/28/2022]
Abstract
The freshwater snail genus Bulinus has been intensively investigated due to its role as intermediate host for trematode blood flukes that cause the debilitating disease schistosomiasis in man and livestock. Owing to taxonomic ambiguities within Bulinus, attention has often focused upon species delineation and several molecular methods have recently been used for identification and characterization purposes. Inspection of compensatory base changes (CBCs) in the secondary structure of the nuclear ribosomal internal transcribed spacer (ITS) has been used to differentiate species in other genera, and here we present a study investigating the presence of CBCs between species in the species groups within Bulinus. CBCs were present within B. forskalii and B. globosus indicating that these widely distributed taxa might constitute cryptic species complexes. However, other currently recognized species could not be distinguished by CBC analysis. The putative secondary structure of the very long ITS2 sequence of the B. reticulatus species group had an additional helix (DIIa) between DII and DIII not seen in other species groups of Bulinus. The accumulation and inspection of further ITS2 sequences will no doubt reveal additional variation between Bulinus populations, and CBCs should be incorporated in future taxonomic work in this group.
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Affiliation(s)
- Aslak Jørgensen
- Laboratory for Molecular Systematics, The Natural History Museum of Denmark, Faculty of Natural Sciences, University of Copenhagen, Sølvgade 83, 1307 Copenhagen K, Denmark.
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Ohshima I, Tanikawa-Dodo Y, Saigusa T, Nishiyama T, Kitani M, Hasebe M, Mohri H. Phylogeny, biogeography, and host–plant association in the subfamily Apaturinae (Insecta: Lepidoptera: Nymphalidae) inferred from eight nuclear and seven mitochondrial genes. Mol Phylogenet Evol 2010; 57:1026-36. [DOI: 10.1016/j.ympev.2010.09.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Revised: 09/20/2010] [Accepted: 09/21/2010] [Indexed: 10/19/2022]
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Jørgensen A, Madsen H, Nalugwa A, Nyakaana S, Rollinson D, Stothard JR, Kristensen TK. A molecular phylogenetic analysis ofBulinus(Gastropoda: Planorbidae) with conserved nuclear genes. ZOOL SCR 2010. [DOI: 10.1111/j.1463-6409.2010.00458.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
AbstractSchistosome parasites commonly show specificity to their intermediate mollusc hosts and the degree of specificity can vary between parasite strains and geographical location. Here the role of miracidial behaviour in host specificity ofSchistosoma haematobiumon the islands of Zanzibar is investigated. In choice-chamber experiments,S. haematobiummiracidia moved towardsBulinus globosussnail hosts in preference to empty chambers. In addition, miracidia preferred uninfected over patentB. globosus. This preference should benefit the parasite as patent snails are likely to have mounted an immune response toS. haematobiumas well as providing poorer resources than uninfected snails. Miracidia also discriminated between the hostB. globosusand the sympatric, non-host speciesCleopatra ferruginea. In contrast,S. haematobiumdid not discriminate against the allopatricBulinus nasutus. Penetration of the host by miracidia was investigated by screening snails 24 h after exposure using polymerase chain reaction (PCR) withS. haematobiumspecificDraI repeat primers. There was no difference in the frequency of penetration ofB. globosusversusB. nasutus. These responses to different snail species may reflect selection pressure to avoid sympatric non-hosts which represent a transmission dead end. The distribution ofB. nasutuson Unguja is outside the endemic zone and so there is less chance of exposure toS. haematobium, hence there will be little selection pressure to avoid this non-host snail.
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Schistosoma haematobium in Lake Malaŵi: susceptibility and molecular diversity of the snail hosts Bulinus globosus and B. nyassanus. J Helminthol 2008; 82:377-82. [PMID: 18752711 DOI: 10.1017/s0022149x08056290] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Intermediate hosts of Schistosoma haematobium, the causative agent of urinary schistosomiasis, in Lake Malaŵi include: Bulinus globosus, a member of the B. africanus group and B. nyassanus, a diploid member of the B. truncatus/tropicus species complex. We compared genetic variability between isolates of S. haematobium from the southern part of the lake (Cape Maclear), where both B. globosus and B. nyassanus play a role as intermediate hosts, and isolates from the northern part, where only B. globosus is host. Data show that the S. haematobium isolates from these two areas of Lake Malaŵi cannot be distinguished using nuclear or mitochondrial sequences and are capable of cross-infections.
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Jørgensen A, Kristensen TK, Madsen H. A molecular phylogeny of apple snails (Gastropoda, Caenogastropoda, Ampullariidae) with an emphasis on African species. ZOOL SCR 2008. [DOI: 10.1111/j.1463-6409.2007.00322.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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