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Pennance T, Calvelo J, Tennessen JA, Burd R, Cayton J, Bollmann SR, Blouin MS, Spaan JM, Hoffmann FG, Ogara G, Rawago F, Andiego K, Mulonga B, Odhiambo M, Loker ES, Laidemitt MR, Lu L, Iriarte A, Odiere MR, Steinauer ML. The genome and transcriptome of the snail Biomphalaria sudanica s.l.: immune gene diversification and highly polymorphic genomic regions in an important African vector of Schistosoma mansoni. BMC Genomics 2024; 25:192. [PMID: 38373909 PMCID: PMC10875847 DOI: 10.1186/s12864-024-10103-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 02/08/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Control and elimination of schistosomiasis is an arduous task, with current strategies proving inadequate to break transmission. Exploration of genetic approaches to interrupt Schistosoma mansoni transmission, the causative agent for human intestinal schistosomiasis in sub-Saharan Africa and South America, has led to genomic research of the snail vector hosts of the genus Biomphalaria. Few complete genomic resources exist, with African Biomphalaria species being particularly underrepresented despite this being where the majority of S. mansoni infections occur. Here we generate and annotate the first genome assembly of Biomphalaria sudanica sensu lato, a species responsible for S. mansoni transmission in lake and marsh habitats of the African Rift Valley. Supported by whole-genome diversity data among five inbred lines, we describe orthologs of immune-relevant gene regions in the South American vector B. glabrata and present a bioinformatic pipeline to identify candidate novel pathogen recognition receptors (PRRs). RESULTS De novo genome and transcriptome assembly of inbred B. sudanica originating from the shoreline of Lake Victoria (Kisumu, Kenya) resulted in a haploid genome size of ~ 944.2 Mb (6,728 fragments, N50 = 1.067 Mb), comprising 23,598 genes (BUSCO = 93.6% complete). The B. sudanica genome contains orthologues to all described immune genes/regions tied to protection against S. mansoni in B. glabrata, including the polymorphic transmembrane clusters (PTC1 and PTC2), RADres, and other loci. The B. sudanica PTC2 candidate immune genomic region contained many PRR-like genes across a much wider genomic region than has been shown in B. glabrata, as well as a large inversion between species. High levels of intra-species nucleotide diversity were seen in PTC2, as well as in regions linked to PTC1 and RADres orthologues. Immune related and putative PRR gene families were significantly over-represented in the sub-set of B. sudanica genes determined as hyperdiverse, including high extracellular diversity in transmembrane genes, which could be under pathogen-mediated balancing selection. However, no overall expansion in immunity related genes was seen in African compared to South American lineages. CONCLUSIONS The B. sudanica genome and analyses presented here will facilitate future research in vector immune defense mechanisms against pathogens. This genomic/transcriptomic resource provides necessary data for the future development of molecular snail vector control/surveillance tools, facilitating schistosome transmission interruption mechanisms in Africa.
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Affiliation(s)
- Tom Pennance
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA.
| | - Javier Calvelo
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Instituto de Higiene, Universidad de La República, Montevideo, 11600, Uruguay
| | | | - Ryan Burd
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | - Jared Cayton
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | | | | | - Johannie M Spaan
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS, USA
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, USA
| | - George Ogara
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Fredrick Rawago
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Kennedy Andiego
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Boaz Mulonga
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Meredith Odhiambo
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Eric S Loker
- Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Martina R Laidemitt
- Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Lijun Lu
- Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Andrés Iriarte
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Instituto de Higiene, Universidad de La República, Montevideo, 11600, Uruguay
| | - Maurice R Odiere
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Michelle L Steinauer
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA.
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Duguay C, Mosha JF, Lukole E, Mangalu D, Thickstun C, Mallya E, Aziz T, Feng C, Protopopoff N, Mosha F, Manjurano A, Krentel A, Kulkarni MA. Assessing risk factors for malaria and schistosomiasis among children in Misungwi, Tanzania, an area of co-endemicity: A mixed methods study. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002468. [PMID: 37992045 PMCID: PMC10664891 DOI: 10.1371/journal.pgph.0002468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 11/24/2023]
Abstract
Malaria and schistosomiasis are two major parasitic vector-borne diseases that are a particular threat to young children in Sub-Saharan Africa. In the present study, we investigated factors that are associated with malaria, schistosomiasis, and co-infection among school-aged children, using an explanatory sequential mixed-methods approach. A cross-sectional study was conducted in January 2022 in Misungwi, Tanzania, that sampled 1,122 children aged 5 to 14 years old for malaria and schistosomiasis infection. Mixed-effect logistic regression models were used to assess the association between infection prevalence or seroprevalence, and environmental determinants that create favorable conditions for vectors and parasites and social determinants that relate to disease exposure. Community mapping combined with direct field observations were conducted in August 2022 in three selected villages from the cross-sectional study to understand specific water use behaviors and to identify potential malaria mosquito larval breeding sites and freshwater snail habitat. The prevalence of malaria, seroprevalence of schistosomiasis, and co-infection in this study were 40.4%, 94.3%, and 38.1%, respectively. Individual-level factors emerged as the primary determinants driving the association with infection, with age (every one-year increase in age) and sex (boys vs girls) being statistically and positively associated with malaria, schistosomiasis, and co-infection (P<0.05 for all). Community maps identified many unimproved water sources in all three villages that were used by humans, cattle, or both. We found that children primarily fetched water, and that unprotected wells were dedicated for drinking water whereas ponds were dedicated for other domestic uses and cattle. Although not identified in the community maps, we found hand pumps in all three villages were not in use because of unpleasant taste and high cost. This study improves our understanding of individual, social and environmental factors that are associated with malaria, schistosomiasis, and co-infection, which can inform potential entry points for integrated disease prevention and control.
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Affiliation(s)
- Claudia Duguay
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Jacklin F. Mosha
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Eliud Lukole
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Doris Mangalu
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Charles Thickstun
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Elizabeth Mallya
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Tatu Aziz
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Cindy Feng
- Department of Community Health & Epidemiology, Dalhousie University, Halifax, Canada
| | - Natacha Protopopoff
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Franklin Mosha
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Alphaxard Manjurano
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Alison Krentel
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
- Bruyère Research Institute, Ottawa, Ontario, Canada
| | - Manisha A. Kulkarni
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
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Pennance T, Calvelo J, Tennessen JA, Burd R, Cayton J, Bollmann SR, Blouin MS, Spaan JM, Hoffmann FG, Ogara G, Rawago F, Andiego K, Mulonga B, Odhiambo M, Loker ES, Laidemitt MR, Lu L, Iriarte A, Odiere M, Steinauer ML. The genome and transcriptome of the snail Biomphalaria sudanica s.l.: Immune gene diversification and highly polymorphic genomic regions in an important African vector of Schistosoma mansoni. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.01.565203. [PMID: 37961413 PMCID: PMC10635097 DOI: 10.1101/2023.11.01.565203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Control and elimination of schistosomiasis is an arduous task, with current strategies proving inadequate to break transmission. Exploration of genetic approaches to interrupt Schistosoma mansoni transmission, the causative agent for human intestinal schistosomiasis in sub-Saharan Africa and South America, has led to genomic research of the snail vector hosts of the genus Biomphalaria. Few complete genomic resources exist, with African Biomphalaria species being particularly underrepresented despite this being where the majority of S. mansoni infections occur. Here we generate and annotate the first genome assembly of Biomphalaria sudanica sensu lato, a species responsible for S. mansoni transmission in lake and marsh habitats of the African Rift Valley. Supported by whole-genome diversity data among five inbred lines, we describe orthologs of immune-relevant gene regions in the South American vector B. glabrata and present a bioinformatic pipeline to identify candidate novel pathogen recognition receptors (PRRs). Results De novo genome and transcriptome assembly of inbred B. sudanica originating from the shoreline of Lake Victoria (Kisumu, Kenya) resulted in a haploid genome size of ~944.2 Mb (6732 fragments, N50=1.067 Mb), comprising 23,598 genes (BUSCO=93.6% complete). The B. sudanica genome contains orthologues to all described immune genes/regions tied to protection against S. mansoni in B. glabrata. The B. sudanica PTC2 candidate immune genomic region contained many PRR-like genes across a much wider genomic region than has been shown in B. glabrata, as well as a large inversion between species. High levels of intra-species nucleotide diversity were seen in PTC2, as well as in regions linked to PTC1 and RADres orthologues. Immune related and putative PRR gene families were significantly over-represented in the sub-set of B. sudanica genes determined as hyperdiverse, including high extracellular diversity in transmembrane genes, which could be under pathogen-mediated balancing selection. However, no overall expansion in immunity related genes were seen in African compared to South American lineages. Conclusions The B. sudanica genome and analyses presented here will facilitate future research in vector immune defense mechanisms against pathogens. This genomic/transcriptomic resource provides necessary data for the future development of molecular snail vector control/surveillance tools, facilitating schistosome transmission interruption mechanisms in Africa.
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Affiliation(s)
- Tom Pennance
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | - Javier Calvelo
- Laboratorio Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | | | - Ryan Burd
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | - Jared Cayton
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | | | | | - Johannie M Spaan
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS USA
| | - George Ogara
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Fredrick Rawago
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Kennedy Andiego
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Boaz Mulonga
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Meredith Odhiambo
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Eric S Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A
| | - Martina R Laidemitt
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A
| | - Lijun Lu
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A
| | - Andrés Iriarte
- Laboratorio Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | - Maurice Odiere
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS USA
| | - Michelle L Steinauer
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
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Wepnje GB, Peters MK, Green AE, Nkuizin TE, Kenko DBN, Dzekashu FF, Kimbi HK, Anchang-Kimbi JK. Seasonal and environmental dynamics of intra-urban freshwater habitats and their influence on the abundance of Bulinus snail host of Schistosoma haematobium in the Tiko endemic focus, Mount Cameroon region. PLoS One 2023; 18:e0292943. [PMID: 37856526 PMCID: PMC10586688 DOI: 10.1371/journal.pone.0292943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 10/02/2023] [Indexed: 10/21/2023] Open
Abstract
Urogenital schistosomiasis (UGS) caused by Schistosoma haematobium is endemic in the South West Region of Cameroon. An understanding of the abundance and distribution of the Bulinus snail, intermediate host can inform strategic snail control programmes at a local scale. This study investigated seasonal dynamics and environmental factors influencing occurrence and abundance of freshwater snail intermediate hosts in Tiko, a semi-urban endemic focus in the Mount Cameroon area. A longitudinal malacological field survey was conducted between December 2019 and December 2020 in the Tiko municipality. Snails were collected for one year monthly at 12 different human water contact sites along a stretch of the Ndongo stream using a standardized sampling technique. Freshwater snails were identified using shell morphological features. In addition, water temperature, pH, electrical conductivity, total dissolved solutes, salinity, water depth, width and flow velocity were measured, and vegetation cover as well as substrate type were determined. Bayesian regression models were used to identify the main environmental factors affecting the occurrence and abundance of Bulinus intermediate host. In total, 2129 fresh water snails were collected during the study period. Physa (51.4%) was the most abundant genus followed by Melanoides (28.6%) then, Bulinus (15.5%), Lymnaea (4.2%), Indoplanorbis (0.2%) and Potadoma (0.1%). Seasonality in abundance was significant in Bulinus sp as well as other genera, with greater numbers in the dry season (peaks between December and February). Water temperature, a rocky or sandy substrate type associated positively with Bulinus sp, meanwhile a higher water flow rate and medium vegetation negatively influenced the snail intermediate host population. These findings underscore the importance of timing behavioural and snail control interventions against schistosomiasis as well as increase vigilance of other trematode diseases in the study area. The continuous spread of planorbid snail hosts is a major concern.
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Affiliation(s)
- Godlove Bunda Wepnje
- Department of Animal Biology and Conservation, Faculty of Science, University of Buea, Buea, Cameroon
| | - Marcell K. Peters
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Adeline Enjema Green
- Department of Animal Biology and Conservation, Faculty of Science, University of Buea, Buea, Cameroon
| | - Tingmi Emparo Nkuizin
- Department of Animal Biology and Conservation, Faculty of Science, University of Buea, Buea, Cameroon
| | | | - Fairo F. Dzekashu
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Helen Kuokuo Kimbi
- Department of Animal Biology and Conservation, Faculty of Science, University of Buea, Buea, Cameroon
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Bamenda, Bambili, Cameroon
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States of America
| | - Judith Kuoh Anchang-Kimbi
- Department of Animal Biology and Conservation, Faculty of Science, University of Buea, Buea, Cameroon
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Andrus PS, Stothard JR, Wade CM. Seasonal patterns of Schistosoma mansoni infection within Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria. PLoS Negl Trop Dis 2023; 17:e0011506. [PMID: 37578945 PMCID: PMC10424865 DOI: 10.1371/journal.pntd.0011506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/06/2023] [Indexed: 08/16/2023] Open
Abstract
Intestinal schistosomiasis is hyperendemic in many sub-Saharan African countries. In Uganda, it is endemic at both Lake Albert (LA) and Lake Victoria (LV) and caused by S. mansoni that uses Biomphalaria snails as obligatory intermediate snail hosts. To shed light on local patterns of infection, we utilised two PCR-based methods to detect S. mansoni within Biomphalaria spp. as collected at the Ugandan shorelines of Lake Albert and Lake Victoria from 2009-2010. Overall, at our Lake Albert sites, the mean infection prevalence was 12.5% (15 of 120 snails), while at our Lake Victoria sites the prevalence was 5% (3 of 60 snails). At our Lake Albert sites, the highest infection prevalence of 13.3% (8 of 60 snails) was at Walukuba, while at our Lake Victoria sites, the highest infection prevalence of 10% (2 of 20 snails) was at Lwanika. Three species of Biomphalaria, B. pfeifferi, B. stanleyi and B. sudanica, were identified at our Lake Albert collection sites, while only a single species, B. choanomphala, was identified at our Lake Victoria collection sites. Biomphalaria stanleyi (2 of 20 snails; 15%) had the highest infection prevalence, followed by B. sudanica (5 of 60 snails; 13.3%), B. pfeifferi (4 of 40 snails; 10%) and B. choanomphala (3 of 60 snails; 5%). Of the Biomphalaria species identified, B. choanomphala had the highest haplotype (gene) diversity score, followed by B. stanleyi, B. sudanica and B. pfeifferi. Sites with a higher mean prevalence of S. mansoni infection had higher intra-species haplotype diversity scores than sites with a lower mean prevalence. The wet seasons (LA: 13.3%; LV: 8.7%) had a consistently higher mean infection prevalence of S. mansoni than the dry seasons (LA: 9.5%; LV: 5%) for all species and all sites tested at both Lake Albert (n = 480) and Lake Victoria (n = 320), though the difference was not statistically significant.
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Affiliation(s)
- Peter S. Andrus
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - J. Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Christopher M. Wade
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
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Spaan JM, Pennance T, Laidemitt MR, Sims N, Roth J, Lam Y, Rawago F, Ogara G, Loker ES, Odiere MR, Steinauer ML. Multi-strain compatibility polymorphism between a parasite and its snail host, a neglected vector of schistosomiasis in Africa. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2023; 3:100120. [PMID: 37128285 PMCID: PMC10147961 DOI: 10.1016/j.crpvbd.2023.100120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/23/2023] [Indexed: 05/03/2023]
Abstract
Interactions between Schistosoma mansoni and its snail host are understood primarily through experimental work with one South American vector species, Biomphalaria glabrata. However, 90% of schistosomiasis transmission occurs in Africa, where a diversity of Biomphalaria species may serve as vectors. With the long-term goal of determining the genetic and ecological determinants of infection in African snail hosts, we developed genetic models of Biomphalaria sudanica, a principal vector in the African Great Lakes. We determined laboratory infection dynamics of two S. mansoni lines in four B. sudanica lines. We measured the effects of the following variables on infection success and the number of cercariae produced (infection intensity): (i) the combination of parasite and snail line; (ii) the dose of parasites; and (iii) the size of snail at time of exposure. We found one snail line to be almost completely incompatible with both parasite lines, while other snail lines showed a polymorphism in compatibility: compatible with one parasite line while incompatible with another. Interestingly, these patterns were opposite in some of the snail lines. The parasite-snail combination had no significant effect on the number of cercariae produced in a successful infection. Miracidia dose had a strong effect on infection status, in that higher doses led to a greater proportion of infected snails, but had no effect on infection intensity. In one of the snail-schistosome combinations, snail size at the time of exposure affected both infection status and cercarial production in that the smallest size class of snails (1.5-2.9 mm) had the highest infection rates, and produced the greatest number of cercariae, suggesting that immunity increases with age and development. The strongest predictor of the infection intensity was the size of snail at the time of shedding: 1 mm of snail growth equated to a 19% increase in cercarial production. These results strongly suggest that infection status is determined in part by the interaction between snail and schistosome genetic lines, consistent with a gene-for-gene or matching allele model. This foundational work provides rationale for determining the genetic interactions between African snails and schistosomes, which may be applied to control strategies.
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Affiliation(s)
- Johannie M. Spaan
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, OR, USA
| | - Tom Pennance
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, OR, USA
| | - Martina R. Laidemitt
- Department of Biology, University of New Mexico, Albuquerque, USA
- Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, USA
| | - Nicole Sims
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, OR, USA
| | - Jewell Roth
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, OR, USA
| | - Yvonne Lam
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, OR, USA
| | - Fredrick Rawago
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - George Ogara
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Eric S. Loker
- Department of Biology, University of New Mexico, Albuquerque, USA
- Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, USA
| | - Maurice R. Odiere
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, Kenya
| | - Michelle L. Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, OR, USA
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Prevalence of Schistosoma mansoni infection among fishermen in Busega district, Tanzania. PLoS One 2022; 17:e0276395. [PMID: 36441724 PMCID: PMC9704623 DOI: 10.1371/journal.pone.0276395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 10/05/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Schistosoma (S.) mansoni infection is endemic in all regions around Lake Victoria and affects all age groups to different degrees. In most endemic areas, less attention has been paid to determining the prevalence of infection, sanitation status, and knowledge about intestinal schistosomiasis (KIS) in fishermen. Therefore, the purpose of this study was to establish the prevalence of S. mansoni infection and associated factors among fishermen in the Busega district. MATERIALS AND METHODS A cross-sectional study was conducted among fishermen in July, 2020 in five fishing villages in the Busega district located along Lake Victoria. A total of 352 fishermen were interviewed with regard to their sanitation status and level of KIS. A single stool sample from fishermen was examined for S.mansoni eggs by using the Formalin-Ether Concentration technique. The potential factors associated with S. mansoni infection were explored using multivariable logistic regression. RESULTS The prevalence of S. mansoni infection was high (65.0%) among fishermen and varied with age, whereby fishermen aged ≤36 years had the highest prevalence. Fishermen had a low level of KIS and the majority of them reported practicing open defecation during fishing (81%). These fishermen with a low level of KIS and who reported defecating in open areas during fishing had 2.8 times (95% CI: 1.0-7.2) and 2.1 times (95% CI: 1.1-3.9) higher odds of being infected with S. mansoni than those with a high level of KIS and those who did not report defecating in open areas during fishing, respectively. CONCLUSION S. mansoni infection was high among fishermen in the Busega district. Furthermore, fishermen had a low level of KIS and were reported to have defecated in open areas during fishing. Infection with S. mansoni was associated with age, a low level of KIS and open defecation behaviour during fishing. Therefore, mass drug administration (MDA) with praziquantel, health education, and sanitation behaviour change interventions were needed.
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Parasitological and malacological surveys to identify transmission sites for Schistosoma mansoni in Gomma District, south-western Ethiopia. Sci Rep 2022; 12:17063. [PMID: 36224348 PMCID: PMC9556602 DOI: 10.1038/s41598-022-21641-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 09/29/2022] [Indexed: 12/30/2022] Open
Abstract
Schistosomiasis is a neglected tropical disease that disproportionately affects the poorest people in tropical and subtropical countries. It is a major parasitic disease causing considerable morbidity in Ethiopia. Despite significant control efforts, schistosomiasis transmission is still widespread in many rural areas of the country. The aim of this study was to determine the prevalence and intensity of intestinal schistosomiasis among schoolchildren, as well as to identify schistosomiasis transmission sites in Gomma District, southwestern Ethiopia. Between October 2018 and September 2019, cross-sectional parasitological and malacological surveys were conducted in the study area. The study comprised 492 school-children aged 6 to 15 years old from four primary schools in Gomma District. To identify and quantify eggs of Schistosoma mansoni from the children, stool specimens were collected and processed using double Kato-Katz thick smears. Water bodies adjacent to human settlements in the study area were surveyed for snail intermediate hosts of S. mansoni. Morphological identification of collected snails was conducted, followed by examining their infection status using a dissecting microscope. The overall prevalence of S. mansoni infection was 73.8% (95%CI: 69.9-77.7%) and 41.6% of them had moderate-to-heavy infections. The prevalence of S. mansoni infection differed considerably by age group, with the older age groups (12-15) having a higher prevalence than the younger age groups (6-11) (p < 0.001). The prevalence of infection also varied significantly among schools; Dedo Ureche had the highest prevalence (86.9%) (p = 0.034), while Goga Kilole had relatively the lowest prevalence of S. mansoni infection (59.6%) (p = 0.003). A total of 1463 Biomphalaria pfeifferi snails were collected from 11 survey sites throughout the study area, with 357 (24.4%) of the snails shedding schistosomes cercariae. Despite intensified efforts to scale up mass drug administration in Ethiopia, this study reported high levels of S. mansoni infection among schoolchildren and snail intermediate hosts in rural communities in Gomma. Such a high infection rate warrants pressing needs for targeted and integrated interventions to control the disease in the area.
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Hailegebriel T, Nibret E, Munshea A. Distribution and seasonal abundance of Biomphalaria snails and their infection status with Schistosoma mansoni in and around Lake Tana, northwest Ethiopia. Sci Rep 2022; 12:17055. [PMID: 36224227 PMCID: PMC9556671 DOI: 10.1038/s41598-022-21306-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/26/2022] [Indexed: 12/30/2022] Open
Abstract
Biomphalaria snails, namely B. pfeifferi and B. sudanica, are the principal intermediate hosts for Schistosoma mansoni infection in Ethiopia. Epidemiological studies of Biomphalaria snails and their infection status with S. mansoni is vital for public health planning. This study aimed to assess the spatial and seasonal abundance of Biomphalaria snails as well as their infection status with S. mansoni around Lake Tana, northwest Ethiopia. Malacological survey was conducted from January 2021 to December 2021 in ten different collection sites in and around Lake Tana. Snail collection was performed for 20 min from each collection site seasonally (four times in a year) using a standard scoop and handpicking from aquatic vegetation. All collected snails were carefully examined based on their morphological features and all live Biomphalaria snails were subjected to cercariae shedding experiment. Descriptive statistics were used to determine the prevalence of S. mansoni infection and its relationship with snail collection sites and seasons. A total of 3886 freshwater snails were collected from ten collection sites around Lake Tana. Out of the total snails collected, 1606 (41.3%; 95% CI 39.77-42.89%) were Biomphalaria spp. The highest (374) and the lowest numbers (98) of Biomphalaria snails were collected from Shinne River and Qunzela Lakeshore, respectively. Out of the 1375 live Biomphalaria snails, 14.4% (95% CI 12.59-16.37%) snails shed cercariae, but only 4.87% (95% CI 3.79-6.15%) were cercariae of S. mansoni. The infection prevalence of S. mansoni ranged from 10.59% at the Cherechera site to 1.49% at Gumara River. Biomphalaria snail infections with S. mansoni cercariae were observed throughout the season, the highest and the lowest infection rates being in the spring and summer seasons. Significant differences in the prevalence of S. mansoni infection in Biomphalaria snails were observed across study sites and seasons (p < 0.05). Biomphalaria snails were the most abundant freshwater snails found in nearly all of snail collection sites throughout the year. It was revealed that nearly five percent of Biomphalaria snails were infected with S. mansoni cercariae. This study highlights the importance of appropriate snail control strategies to support the ongoing prevention and control of schistosomiasis around Lake Tana.
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Affiliation(s)
- Tamirat Hailegebriel
- grid.442845.b0000 0004 0439 5951Department of Biology, College of Science, Bahir Dar University, Bahir Dar, Ethiopia ,grid.442845.b0000 0004 0439 5951Institute of Biotechnology (IOB), Bahir Dar University, Bahir Dar, Ethiopia
| | - Endalkachew Nibret
- grid.442845.b0000 0004 0439 5951Department of Biology, College of Science, Bahir Dar University, Bahir Dar, Ethiopia ,grid.442845.b0000 0004 0439 5951Institute of Biotechnology (IOB), Bahir Dar University, Bahir Dar, Ethiopia
| | - Abaineh Munshea
- grid.442845.b0000 0004 0439 5951Department of Biology, College of Science, Bahir Dar University, Bahir Dar, Ethiopia ,grid.442845.b0000 0004 0439 5951Institute of Biotechnology (IOB), Bahir Dar University, Bahir Dar, Ethiopia
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Systematic Review and Meta-Analysis on the Infection Rates of Schistosome Transmitting Snails in Southern Africa. Trop Med Infect Dis 2022; 7:tropicalmed7050072. [PMID: 35622699 PMCID: PMC9145527 DOI: 10.3390/tropicalmed7050072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/21/2022] [Accepted: 04/21/2022] [Indexed: 02/05/2023] Open
Abstract
Efforts to interrupt and eliminate schistosomiasis as a public health problem have increased in several Southern African countries. A systematic review was carried out on the infection rates of snails that cause schistosomiasis in humans. The searches were conducted in PubMed, Web of Science, and Scopus databases, using the PRISMA guidelines from inception to 24 February 2022. The study quality was assessed by using the Joanna Briggs Institute prevalence critical appraisal checklist. Pooled infection rates were estimated by using an inverse variance heterogeneity model, while heterogeneity was determined by using Cochran’s Q test and Higgins i2 statistics. A total of 572 articles were screened, but only 28 studies were eligible for inclusion based on predetermined criteria. In the selected studies, 82,471 Bulinus spp. and 16,784 Biomphalaria spp. snails were screened for cercariae. The pooled infectivity of schistosome intermediate host snails, Biomphalaria spp., and Bulinus spp. were 1%, 2%, and 1%, respectively. Snail infection rates were higher in the 1900s compared to the 2000s. A Luis Furuya–Kanamori index of 3.16 indicated publication bias, and a high level of heterogeneity was observed. Although snail infectivity in Southern Africa is relatively low, it falls within the interval of common snail infection rates, thus indicating the need for suitable snail control programs that could interrupt transmission and achieve elimination.
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Laidemitt MR, Gleichsner AM, Ingram CD, Gay SD, Reinhart EM, Mutuku MW, Oraro P, Minchella DJ, Mkoji GM, Loker ES, Steinauer ML. Host preference of field‐derived
Schistosoma mansoni
is influenced by snail host compatibility and infection status. Ecosphere 2022; 13. [PMID: 36285193 PMCID: PMC9592064 DOI: 10.1002/ecs2.4004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Schistosome parasites cause a chronic inflammatory disease in humans, and recent studies have emphasized the importance of control programs for understanding the aquatic phases of schistosomiasis transmission. The host-seeking behavior of larval schistosomes (miracidia) for their snail intermediate hosts plays a critical role in parasite transmission. Using field-derived strains of Kenyan snails and parasites, we tested two main hypotheses: (1) Parasites prefer the most compatible host, and (2) parasites avoid hosts that are already infected. We tested preference to three Biomphalaria host snail taxa (B. pfeifferi, B. sudanica, and B. choanomphala), using allopatric and sympatric Schistosoma mansoni isolates and two different nonhost snail species that co-occur with Biomphalaria, Bulinus globosus, and Physa acuta. We also tested whether schistosomes avoid snail hosts that are already infected by another trematode species and whether competitive dominance played a role in their behavior. Preference was assessed using two-way choice chambers and by visually counting parasites that moved toward competing stimuli. In pairwise comparisons, we found that S. mansoni did not always prefer the more compatible snail taxon, but never favored an incompatible host over a compatible host. While parasites preferred B. pfeifferi to the nonhost species B. globosus, they did not significantly prefer B. pfeifferi versus P. acuta, an introduced species in Kenya. Finally, we demonstrated that parasites avoid infected snails if the resident parasite was competitively dominant (Patagifer sp.), and preferred snails infected with subordinates (xiphidiocercariae) to uninfected snails. These results provide evidence of “fine tuning” in the ability of schistosome miracidia to detect hosts; however, they did not always select hosts that would maximize fitness. Appreciating such discriminatory abilities could lead to a better understanding of how ecosystem host and parasite diversity influences disease transmission and could provide novel control mechanisms to improve human health.
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Affiliation(s)
- Martina R. Laidemitt
- Center for Evolutionary and Theoretical Immunology, Department of Biology University of New Mexico Albuquerque New Mexico USA
| | - Alyssa M. Gleichsner
- Department of Biological Sciences State University of New York, College at Plattsburgh Plattsburgh New York USA
| | - Christopher D. Ingram
- College of Osteopathic Medicine of the Pacific Northwest Western University of Health Sciences Lebanon Oregon USA
| | - Steven D. Gay
- College of Osteopathic Medicine of the Pacific Northwest Western University of Health Sciences Lebanon Oregon USA
| | | | - Martin W. Mutuku
- Center for Biotechnology Research and Development Kenya Medical Research Institute (KEMRI) Nairobi Kenya
| | - Polycup Oraro
- Center for Biotechnology Research and Development Kenya Medical Research Institute (KEMRI) Nairobi Kenya
| | - Dennis J. Minchella
- Department of Biological Sciences Purdue University West Lafayette Indiana USA
| | - Gerald M. Mkoji
- Center for Biotechnology Research and Development Kenya Medical Research Institute (KEMRI) Nairobi Kenya
| | - Eric S. Loker
- Center for Evolutionary and Theoretical Immunology, Department of Biology University of New Mexico Albuquerque New Mexico USA
| | - Michelle L. Steinauer
- College of Osteopathic Medicine of the Pacific Northwest Western University of Health Sciences Lebanon Oregon USA
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Trienekens SCM, Faust CL, Besigye F, Pickering L, Tukahebwa EM, Seeley J, Lamberton PHL. Variation in water contact behaviour and risk of Schistosoma mansoni (re)infection among Ugandan school-aged children in an area with persistent high endemicity. Parasit Vectors 2022; 15:15. [PMID: 34991702 PMCID: PMC8734346 DOI: 10.1186/s13071-021-05121-6] [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: 08/26/2021] [Accepted: 12/11/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Annual mass drug administration with praziquantel has reduced schistosomiasis transmission in some highly endemic areas, but areas with persistent high endemicity have been identified across sub-Saharan Africa, including Uganda. In these areas many children are rapidly reinfected post treatment, while some children remain uninfected or have low-intensity infections. The aim of this mixed-methods study was to better understand variation in water contact locations, behaviours and infection risk in school-aged children within an area with persistent high endemicity to inform additional control efforts. METHODS Data were collected in Bugoto, Mayuge District, Uganda. Two risk groups were identified from a longitudinal cohort, and eight children with no/low-intensity infections and eight children with reinfections were recruited. Individual structured day-long observations with a focus on water contact were conducted over two periods in 2018. In all identified water contact sites, four snail surveys were conducted quarterly over 1 year. All observed Biomphalaria snails were collected, counted and monitored in the laboratory for Schistosoma mansoni cercarial shedding for 3 weeks. RESULTS Children came into contact with water for a range of purposes, either directly at the water sources or by coming into contact with water collected previously. Although some water contact practices were similar between the risk groups, only children with reinfection were observed fetching water for commercial purposes and swimming in water sources; this latter group of children also came into contact with water at a larger variety and number of sites compared to children with no/low-intensity infection. Households with children with no/low-intensity infections collected rainwater more often. Water contact was observed at 10 sites throughout the study, and a total of 9457 Biomphalaria snails were collected from these sites over four sampling periods. Four lake sites had a significantly higher Biomphalaria choanomphala abundance, and reinfected children came into contact with water at these sites more often than children with no/low-intensity infections. While only six snails shed cercariae, four were from sites only contacted by reinfected children. CONCLUSIONS Children with reinfection have more high-risk water contact behaviours and accessed water sites with higher B. choanomphala abundance, demonstrating that specific water contact behaviours interact with environmental features to explain variation in risk within areas with persistent high endemicity. Targeted behaviour change, vector control and safe water supplies could reduce reinfection in school-aged children in these settings.
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Affiliation(s)
- Suzan C. M. Trienekens
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Institute of Health & Wellbeing, College of Social Sciences, University of Glasgow, Glasgow, UK
| | - Christina L. Faust
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Fred Besigye
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Lucy Pickering
- Institute of Health & Wellbeing, College of Social Sciences, University of Glasgow, Glasgow, UK
| | | | - Janet Seeley
- Medical Research Council/Uganda Virus Research Institute, Entebbe, Uganda
- Department of Global Health and Development, Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
| | - Poppy H. L. Lamberton
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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13
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Mutuku MW, Laidemitt MR, Spaan JM, Mwangi IN, Ochanda H, Steinauer ML, Loker ES, Mkoji GM. Comparative Vectorial Competence of Biomphalaria sudanica and Biomphalaria choanomphala, Snail Hosts of Schistosoma mansoni, From Transmission Hotspots In Lake Victoria, Western Kenya. J Parasitol 2021; 107:349-357. [PMID: 33906231 DOI: 10.1645/20-138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Schistosoma mansoni, which causes human intestinal schistosomiasis, continues to be a major public health concern in the Lake Victoria basin in western Kenya, with Biomphalaria sudanica (a shoreline inhabiting snail) and Biomphalaria choanomphala (a deep-water snail) playing roles in transmission. A recent study showed that B. sudanica was abundantly present near all study villages on the lakeshore, but B. choanomphala was significantly more abundant near villages known to be persistent transmission hotspots. The present study investigated the relative compatibility of B. sudanica and B. choanomphala with S. mansoni. A reciprocal cross-infection experiment used young adult F1 generation B. sudanica and B. choanomphala that were exposed to either 1, 5, or 10 sympatric or allopatric human-derived S. mansoni miracidia. Three weeks post-exposure (PE) and weekly thereafter, the snails were counted and screened for schistosome cercariae, and at 7 wk PE, total cercariae shed during a 2 hr period by each infected snail was determined. Pre-patent periods for S. mansoni in both B. sudanica and B. choanomphala were similar, and most snails in all exposure combinations started shedding cercariae 5 wk PE. Prevalences were significantly higher in B. choanomphala (12.2-80.9%) than in B. sudanica (5.2-18.6%) at each dose, regardless of whether miracidia were of an allopatric or a sympatric source (P < 0.0001). Overall, the odds of a snail becoming infected with 5 or 10 miracidia were significantly higher than the odds of being infected with 1 miracidium, (P < 0.0001), and fewer cercariae were produced by snails exposed to single as compared to 5 or 10 miracidia. On average, B. choanomphala produced more cercariae ( = 458, SD = 414) than B. sudanica ( = 238, SD = 208) (P < 0.0001). These results suggest that B. choanomphala is more compatible with S. mansoni than B. sudanica. Though B. choanomphala can be found in shallow shoreline waters, it is, for the most part, a deeper-water taxon. Because dredging is a relatively inefficient means of sampling, B. choanomphala is likely underestimated with respect to its population size, the number of S. mansoni-positive snails, and its role in maintaining transmission.
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Affiliation(s)
- Martin W Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya.,School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya
| | - Martina R Laidemitt
- Center for Evolutionary and Theoretical Immunology, Parasitology Division, Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
| | - Johannie M Spaan
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Ibrahim N Mwangi
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Horace Ochanda
- School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya
| | - Michelle L Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Eric S Loker
- Center for Evolutionary and Theoretical Immunology, Parasitology Division, Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
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Manyangadze T, Chimbari MJ, Rubaba O, Soko W, Mukaratirwa S. Spatial and seasonal distribution of Bulinus globosus and Biomphalaria pfeifferi in Ingwavuma, uMkhanyakude district, KwaZulu-Natal, South Africa: Implications for schistosomiasis transmission at micro-geographical scale. Parasit Vectors 2021; 14:222. [PMID: 33892778 PMCID: PMC8063378 DOI: 10.1186/s13071-021-04720-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/06/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Schsistosomiasis is endemic in sub-Saharan Africa. It is transmitted by intermediate host snails such as Bulinus and Biomphalaria. An understanding of the abundance and distribution of snail vectors is important in designing control strategies. This study describes the spatial and seasonal variation of B. globosus and Bio. pfeifferi and their schistosome infection rates between May 2014 and May 2015 in Ingwavuma, uMkhanyakude district, KwaZulu-Natal province, South Africa. METHODS Snail sampling was done on 16 sites once every month by two people for 30 min at each site using the scooping and handpicking methods. Snails collected from each site were screened for schistosome mammalian cercariae by the shedding method. The negative binomial generalised linear mixed model (glmm) was used to determine the relationship between abundances of the intermediate host snails and climatic factors [rainfall, land surface temperatures (LST), seasons, habitats, sampling sites and water physico-chemical parameters including pH and dissolved oxygen (DO)]. RESULTS In total, 1846 schistosomiasis intermediate host snails were collected during the study period. Biompharia pfeifferi was more abundant (53.36%, n = 985) compared to B. globosus (46.64%, n = 861). Bulinus globosus was recorded at 12 sites (75%) and Bio. pfeifferi was present at 7 sites (43.8%). Biompharia pfeifferi cohabited with B. globosus at all the sites it was present. High numbers of Bio. pfeifferi (n = 872, 88.5%) and B. globosus (n = 705, 81.9%) were found between winter and mid-spring. Monthly rainfall showed a statistically significant negative relationship with the abundance of B. globosus (p < 0.05). Dissolved oxygen (DO) had a statistically significant positive relationship with the abundance of Bio. pfeifferi (p < 0.05) while (LST) had a statistically significant negative relationship (p < 0.05). More B. globosus (8.9%, n = 861) were shedding schistosome mammalian cercariae compared to Bio. pfeifferi (0.1%, n = 985) confirming the already documented high prevalence of S. haematobium in Ingwavuma compared to S. mansoni. CONCLUSION Results of this study provide updated information on the distribution of schistosomiasis intermediate host snails in the study area and contributes towards the understanding of the transmission dynamics of schistosomiasis at the micro-geographical scale in this area.
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Affiliation(s)
- Tawanda Manyangadze
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa.
- Geography Department, Faculty of Science and Engineering, Bindura University of Science Education, Bag 1020, Bindura, Zimbabwe.
| | - Moses John Chimbari
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Owen Rubaba
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - White Soko
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
- Ministry of Health and Child Care, De Beers Research Laboratory, P. O. Box 197, Chiredzi, Zimbabwe
| | - Samson Mukaratirwa
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
- Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, St Kitts and Nevis
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Colley DG, Jacobson JA, Binder S. Schistosomiasis Consortium for Operational Research and Evaluation (SCORE): Its Foundations, Development, and Evolution. Am J Trop Med Hyg 2020; 103:5-13. [PMID: 32400343 PMCID: PMC7351300 DOI: 10.4269/ajtmh.19-0785] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in late 2008 to conduct operational research that would inform practices related to the control and elimination of schistosomiasis. This article traces SCORE’s beginnings and underpinnings. These include an emphasis on openness and contributing to the development of a cohesive schistosomiasis control community, building linkages between researchers and national programs, and focusing on answering questions that will help Neglected Tropical Disease program managers to better control and eliminate schistosomiasis. It describes the development and implementation of SCORE’s multiple projects. SCORE began by drawing on advice from a broad range of experts by holding wide-ranging meetings that informed the priorities and protocols for SCORE research. SCORE’s major efforts included large, multicountry field studies comparing multiple strategies for mass drug administration with praziquantel, assessment of approaches to elimination, evaluation of a point-of-care assay for field mapping Schistosoma mansoni, and increasing the sensitivity of a laboratory-based diagnostic. SCORE also supported studies on morbidity due to schistosomiasis, quantification of vector snails and the detection of schistosome infections in snails, and changes in schistosome population genetics under praziquantel drug pressure. SCORE data and specimens are archived and will remain available for future research. Although much remains to be carried out, our hope is that through the already published articles and SCORE results described in this supplement, we will have provided a body of evidence to assist policy makers in the development of judicious guidelines for the control and elimination of schistosomiasis.
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Affiliation(s)
- Daniel G Colley
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia.,Department of Microbiology, University of Georgia, Athens, Georgia
| | | | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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Prevalence of Schistosoma mansoni and S. haematobium in Snail Intermediate Hosts in Africa: A Systematic Review and Meta-analysis. J Trop Med 2020; 2020:8850840. [PMID: 32963554 PMCID: PMC7492904 DOI: 10.1155/2020/8850840] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/23/2022] Open
Abstract
Background Schistosomiasis is caused by Schistosoma mansoni and S. haematobium in Africa. These schistosome parasites use freshwater snail intermediate hosts to complete their lifecycle. Varied prevalence rates of these parasites in the snail intermediate hosts were reported from several African countries, but there were no summarized data for policymakers. Therefore, this study was aimed to systematically summarize the prevalence and geographical distribution of S. mansoni and S. haematobium among freshwater snails in Africa. Methods Literature search was carried out from PubMed, Science Direct, and Scopus which reported the prevalence of S. mansoni and S. haematobium among freshwater snails in Africa. The pooled prevalence was determined using a random-effect model, while heterogeneities between studies were evaluated by I2 test. The meta-analyses were conducted using Stata software, metan command. Results A total of 273,643 snails were examined for the presence of S. mansoni and S. haematobium cercaria in the eligible studies. The pooled prevalence of schistosome cercaria among freshwater snails was 5.5% (95% CI: 4.9–6.1%). The pooled prevalence of S. mansoni and S. haematobium cercaria was 5.6% (95% CI: 4.9–6.3%) and 5.2% (95% CI: 4.6–5.7%), respectively. The highest pooled prevalence was observed from Nigeria (19.0%; 95% CI: 12.7–25.3%), while the lowest prevalence was reported from Chad (0.05%; 95% CI: 0.03–0.13). Higher prevalence of schistosome cercaria was observed from Bulinus globosus (12.3%; 95% CI: 6.2–18.3%) followed by Biomphalaria sudanica (6.7%; 95% CI: 4.5–9.0%) and Biomphalaria pfeifferi (5.1%; 95% CI: 4.1–6.2%). The pooled prevalence of schistosome cercaria obtained using PCR was 26.7% in contrast to 4.5% obtained by shedding cercariae. Conclusion This study revealed that nearly 6% of freshwater snails in Africa were infected by either S. haematobium or S. mansoni. The high prevalence of schistosomes among freshwater snails highlights the importance of appropriate snail control strategies in Africa.
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Chibwana FD, Tumwebaze I, Mahulu A, Sands AF, Albrecht C. Assessing the diversity and distribution of potential intermediate hosts snails for urogenital schistosomiasis: Bulinus spp. (Gastropoda: Planorbidae) of Lake Victoria. Parasit Vectors 2020; 13:418. [PMID: 32795373 PMCID: PMC7427762 DOI: 10.1186/s13071-020-04281-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 08/03/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The Lake Victoria basin is one of the most persistent hotspots of schistosomiasis in Africa, the intestinal form of the disease being studied more often than the urogenital form. Most schistosomiasis studies have been directed to Schistosoma mansoni and their corresponding intermediate snail hosts of the genus Biomphalaria, while neglecting S. haematobium and their intermediate snail hosts of the genus Bulinus. In the present study, we used DNA sequences from part of the cytochrome c oxidase subunit 1 (cox1) gene and the internal transcribed spacer 2 (ITS2) region to investigate Bulinus populations obtained from a longitudinal survey in Lake Victoria and neighbouring systems during 2010-2019. METHODS Sequences were obtained to (i) determine specimen identities, diversity and phylogenetic positions, (ii) reconstruct phylogeographical affinities, and (iii) determine the population structure to discuss the results and their implications for the transmission and epidemiology of urogenital schistosomiasis in Lake Victoria. RESULTS Phylogenies, species delimitation methods (SDMs) and statistical parsimony networks revealed the presence of two main groups of Bulinus species occurring in Lake Victoria; B. truncatus/B. tropicus complex with three species (B. truncatus, B. tropicus and Bulinus sp. 1), dominating the lake proper, and a B. africanus group, prevalent in banks and marshes. Although a total of 47 cox1 haplotypes, were detected within and outside Lake Victoria, there was limited haplotype sharing (only Haplotype 6 was shared between populations from Lake Victoria open waters and neighbouring aquatic systems) - an indication that haplotypes are specific to habitats. CONCLUSIONS The Bulinus fauna of Lake Victoria consists of at least B. truncatus, B. tropicus, Bulinus sp. 1 (B. trigonus?) and B. ugandae. The occurrence and wide distribution of Bulinus species in Lake Victoria potentially implies the occurrence of urogenital schistosomiasis in communities living along the shores and on islands of the lake who depend solely on the lake for their livelihood. More in-depth studies are needed to obtain a better picture of the extent of the disease in the Lake Victoria basin.
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Affiliation(s)
- Fred D. Chibwana
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
- Department of Zoology and Wildlife Conservation, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Immaculate Tumwebaze
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
| | - Anna Mahulu
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
| | - Arthur F. Sands
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
| | - Christian Albrecht
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
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18
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Allan F, Ame SM, Tian-Bi YNT, Hofkin BV, Webster BL, Diakité NR, N’Goran EK, Kabole F, Khamis IS, Gouvras AN, Emery AM, Pennance T, Rabone M, Kinung’hi S, Hamidou AA, Mkoji GM, McLaughlin JP, Kuris AM, Loker ES, Knopp S, Rollinson D. Snail-Related Contributions from the Schistosomiasis Consortium for Operational Research and Evaluation Program Including Xenomonitoring, Focal Mollusciciding, Biological Control, and Modeling. Am J Trop Med Hyg 2020; 103:66-79. [PMID: 32400353 PMCID: PMC7351297 DOI: 10.4269/ajtmh.19-0831] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/14/2020] [Indexed: 01/05/2023] Open
Abstract
The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was created in 2008 to answer questions of importance to program managers working to reduce the burden of schistosomiasis in Africa. In the past, intermediate host snail monitoring and control was an important part of integrated schistosomiasis control. However, in Africa, efforts to control snails have declined dramatically over the last 30 years. A resurgence of interest in the control of snails has been prompted by the realization, backed by a World Health Assembly resolution (WHA65.21), that mass drug administration alone may be insufficient to achieve schistosomiasis elimination. SCORE has supported work on snail identification and mapping and investigated how xenomonitoring techniques can aid in the identification of infected snails and thereby identify potential transmission areas. Focal mollusciciding with niclosamide was undertaken in Zanzibar and Côte d'Ivoire as a part of elimination studies. Two studies involving biological control of snails were conducted: one explored the association of freshwater riverine prawns and snail hosts in Côte d'Ivoire and the other assessed the current distribution of Procambarus clarkii, the invasive Louisiana red swamp crayfish, in Kenya and its association with snail hosts and schistosomiasis transmission. SCORE also supported modeling studies on the importance of snail control in achieving elimination and a meta-analysis of the impact of molluscicide-based snail control programs on human schistosomiasis prevalence and incidence. SCORE's snail control studies contributed to increased investment in building capacity, and specimens collected during SCORE research deposited in the Schistosomiasis Collections at the Natural History Museum (SCAN) will provide a valuable resource for the years to come.
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Affiliation(s)
- Fiona Allan
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Shaali M. Ame
- Public Health Laboratory - Ivo de Carneri, Pemba, United Republic of Tanzania
| | - Yves-Nathan T. Tian-Bi
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Bruce V. Hofkin
- Department of Biology, University of New Mexico, Albuquerque, New Mexico
| | - Bonnie L. Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Nana R. Diakité
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Eliezer K. N’Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Fatma Kabole
- Neglected Tropical Disease Unit, Unguja, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Iddi S. Khamis
- Neglected Tropical Disease Unit, Unguja, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Anouk N. Gouvras
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Aidan M. Emery
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Tom Pennance
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Muriel Rabone
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Safari Kinung’hi
- National Institute of Medical Research (NIMR) Mwanza Centre, Mwanza, United Republic of Tanzania
| | - Amina Amadou Hamidou
- Réseau International Schistosomoses, Environnement, Aménagement et Lutte (RISEAL-Niger), Niamey, Niger
| | - Gerald M. Mkoji
- Center for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - John P. McLaughlin
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California
| | - Armand M. Kuris
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California
| | - Eric S. Loker
- Department of Biology, University of New Mexico, Albuquerque, New Mexico
| | - Stefanie Knopp
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - David Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
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19
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Fuss A, Mazigo HD, Mueller A. Malacological survey to identify transmission sites for intestinal schistosomiasis on Ijinga Island, Mwanza, north-western Tanzania. Acta Trop 2020; 203:105289. [PMID: 31837312 DOI: 10.1016/j.actatropica.2019.105289] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 11/28/2019] [Accepted: 12/03/2019] [Indexed: 12/18/2022]
Abstract
The role of malacological surveys to identify potential transmission sites for schistosomiasis control in this era of mass drug administration have received little attention. In that context, the present study was conducted to determine the abundance, identity and disease transmission potential of intermediate host snails for intestinal schistosomiasis on Ijinga Island, north-western Tanzania. A cross-sectional malacological study was conducted between February and March 2016 on Ijinga Island, Lake Victoria, north-western Tanzania. Snails were collected at points where humans are in frequent contact with water using a standardized scooping technique and have been identified using shell morphological features. The Schistosoma infection status of the collected snails was determined by using real-time Polymerase Chain Reaction (real-time PCR). A total number of 4,888 snails were putatively identified as Biomphalaria species. A random sample of 788 snails underwent molecular analyses for Schistosoma infection. Overall, 279 (35.4%) of Biomphalaria species were identified to be infected with parasites of the lateral spined S. mansoni group. The findings confirm that Biomphalaria species collected in areas with high human water contacts are infected with Schistosoma and that there is a likeliness of local risk for schistosomiasis transmission at most water contact points around Ijinga Island.
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20
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Mutuku MW, Laidemitt MR, Beechler BR, Mwangi IN, Otiato FO, Agola EL, Ochanda H, Kamel B, Mkoji GM, Steinauer ML, Loker ES. A Search for Snail-Related Answers to Explain Differences in Response of Schistosoma mansoni to Praziquantel Treatment among Responding and Persistent Hotspot Villages along the Kenyan Shore of Lake Victoria. Am J Trop Med Hyg 2020; 101:65-77. [PMID: 31162012 PMCID: PMC6609173 DOI: 10.4269/ajtmh.19-0089] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Following a 4-year annual praziquantel (PZQ) treatment campaign, the resulting prevalence of Schistosoma mansoni was seen to differ among individual villages along the Kenyan shore of Lake Victoria. We have investigated possible inherent differences in snail-related aspects of transmission among such 10 villages, including six persistent hotspot (PHS) villages (≤ 30% reduction in prevalence following repeated treatments) located along the west-facing shore of the lake and four PZQ-responding (RESP) villages (> 30% prevalence reduction following repeated treatment) along the Winam Gulf. When taking into account all sampling sites, times, and water hyacinth presence/absence, shoreline-associated Biomphalaria sudanica from PHS and RESP villages did not differ in relative abundance or prevalence of S. mansoni infection. Water hyacinth intrusions were associated with increased B. sudanica abundance. The deeper water snail Biomphalaria choanomphala was significantly more abundant in the PHS villages, and prevalence of S. mansoni among villages both before and after control was positively correlated with B. choanomphala abundance. Worm recoveries from sentinel mice did not differ between PHS and RESP villages, and abundance of non-schistosome trematode species was not associated with S. mansoni abundance. Biomphalaria choanomphala provides an alternative, deepwater mode of transmission that may favor greater persistence of S. mansoni in PHS villages. As we found evidence for ongoing S. mansoni transmission in all 10 villages, we conclude that conditions conducive for transmission and reinfection occur ubiquitously. This argues for an integrated, basin-wide plan for schistosomiasis control to counteract rapid reinfections facilitated by large snail populations and movements of infected people around the lake.
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Affiliation(s)
- Martin W Mutuku
- School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya.,Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Martina R Laidemitt
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Museum of Southwestern Biology, Parasitology Division, University of New Mexico, Albuquerque, New Mexico
| | - Brianna R Beechler
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon
| | - Ibrahim N Mwangi
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Fredrick O Otiato
- Influenza Surveillance Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Eric L Agola
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Horace Ochanda
- School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya
| | - Bishoy Kamel
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Museum of Southwestern Biology, Parasitology Division, University of New Mexico, Albuquerque, New Mexico
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Michelle L Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon
| | - Eric S Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Museum of Southwestern Biology, Parasitology Division, University of New Mexico, Albuquerque, New Mexico
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21
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Laidemitt MR, Anderson LC, Wearing HJ, Mutuku MW, Mkoji GM, Loker ES. Antagonism between parasites within snail hosts impacts the transmission of human schistosomiasis. eLife 2019; 8:50095. [PMID: 31845890 PMCID: PMC6917487 DOI: 10.7554/elife.50095] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/16/2019] [Indexed: 01/16/2023] Open
Abstract
Human disease agents exist within complex environments that have underappreciated effects on transmission, especially for parasites with multi-host life cycles. We examined the impact of multiple host and parasite species on transmission of the human parasite Schistosoma mansoni in Kenya. We show S. mansoni is impacted by cattle and wild vertebrates because of their role in supporting trematode parasites, the larvae of which have antagonistic interactions with S. mansoni in their shared Biomphalaria vector snails. We discovered the abundant cattle trematode, Calicophoron sukari, fails to develop in Biomphalaria pfeifferi unless S. mansoni larvae are present in the same snail. Further development of S. mansoni is subsequently prevented by C. sukari’s presence. Modeling indicated that removal of C. sukari would increase S. mansoni-infected snails by two-fold. Predictable exploitation of aquatic habitats by humans and their cattle enable C. sukari to exploit S. mansoni, thereby limiting transmission of this human pathogen.
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Affiliation(s)
- Martina R Laidemitt
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States
| | - Larissa C Anderson
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States
| | - Helen J Wearing
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States.,Department of Mathematics and Statistics, University of New Mexico, Albuquerque, United States
| | - Martin W Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Eric S Loker
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States
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22
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Rabone M, Wiethase JH, Allan F, Gouvras AN, Pennance T, Hamidou AA, Webster BL, Labbo R, Emery AM, Garba AD, Rollinson D. Freshwater snails of biomedical importance in the Niger River Valley: evidence of temporal and spatial patterns in abundance, distribution and infection with Schistosoma spp. Parasit Vectors 2019; 12:498. [PMID: 31640811 PMCID: PMC6805334 DOI: 10.1186/s13071-019-3745-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/09/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Sound knowledge of the abundance and distribution of intermediate host snails is key to understanding schistosomiasis transmission and to inform effective interventions in endemic areas. METHODS A longitudinal field survey of freshwater snails of biomedical importance was undertaken in the Niger River Valley (NRV) between July 2011 and January 2016, targeting Bulinus spp. and Biomphalaria pfeifferi (intermediate hosts of Schistosoma spp.), and Radix natalensis (intermediate host of Fasciola spp.). Monthly snail collections were carried out in 92 sites, near 20 localities endemic for S. haematobium. All bulinids and Bi. pfeifferi were inspected for infection with Schistosoma spp., and R. natalensis for infection with Fasciola spp. RESULTS Bulinus truncatus was the most abundant species found, followed by Bulinus forskalii, R. natalensis and Bi. pfeifferi. High abundance was associated with irrigation canals for all species with highest numbers of Bulinus spp. and R. natalensis. Seasonality in abundance was statistically significant in all species, with greater numbers associated with dry season months in the first half of the year. Both B. truncatus and R. natalensis showed a negative association with some wet season months, particularly August. Prevalences of Schistosoma spp. within snails across the entire study were as follows: Bi. pfeifferi: 3.45% (79/2290); B. truncatus: 0.8% (342/42,500); and B. forskalii: 0.2% (24/11,989). No R. natalensis (n = 2530) were infected. Seasonality of infection was evident for B. truncatus, with highest proportions shedding in the middle of the dry season and lowest in the rainy season, and month being a significant predictor of infection. Bulinus spp. and Bi. pfeifferi showed a significant correlation of snail abundance with the number of snails shedding. In B. truncatus, both prevalence of Schistosoma spp. infection, and abundance of shedding snails were significantly higher in pond habitats than in irrigation canals. CONCLUSIONS Evidence of seasonality in both overall snail abundance and infection with Schistosoma spp. in B. truncatus, the main intermediate host in the region, has significant implications for monitoring and interrupting transmission of Schistosoma spp. in the NRV. Monthly longitudinal surveys, representing intensive sampling effort have provided the resolution needed to ascertain both temporal and spatial trends in this study. These data can inform planning of interventions and treatment within the region.
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Affiliation(s)
- Muriel Rabone
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Joris Hendrik Wiethase
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Anouk Nathalie Gouvras
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Tom Pennance
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
- School of Biosciences, Cardiff University, Cardiff, CF10 3AT UK
| | - Amina Amadou Hamidou
- Réseau International Schistosomoses, Environnement Aménagement et Lutte (RISEAL-Niger), 333, Avenue des Zarmakoye, B.P. 13724, Niamey, Niger
| | - Bonnie Lee Webster
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Rabiou Labbo
- Réseau International Schistosomoses, Environnement Aménagement et Lutte (RISEAL-Niger), 333, Avenue des Zarmakoye, B.P. 13724, Niamey, Niger
- Centre de Recherche Médicale et Sanitaire (CERMES), Institut Pasteur International Network, 634 Bd de la Nation, BP 10887, Niamey, Niger
| | - Aidan Mark Emery
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Amadou Djirmay Garba
- Réseau International Schistosomoses, Environnement Aménagement et Lutte (RISEAL-Niger), 333, Avenue des Zarmakoye, B.P. 13724, Niamey, Niger
- World Health Organization, Geneva, Switzerland
| | - David Rollinson
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
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23
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Zhang SM, Bu L, Laidemitt MR, Lu L, Mutuku MW, Mkoji GM, Loker ES. Complete mitochondrial and rDNA complex sequences of important vector species of Biomphalaria, obligatory hosts of the human-infecting blood fluke, Schistosoma mansoni. Sci Rep 2018; 8:7341. [PMID: 29743617 PMCID: PMC5943310 DOI: 10.1038/s41598-018-25463-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/16/2018] [Indexed: 01/24/2023] Open
Abstract
Using high throughput Illumina sequencing technology, we determined complete sequences for the mitochondrial genome (mitogenome) and nuclear ribosomal DNA (rDNA) complex for three African freshwater snail taxa within the genus Biomphalaria, B. pfeifferi, B. sudanica and B. choanomphala, and for two laboratory strains of B. glabrata originating from the Neotropics. Biomphalaria snails are obligate vectors of the blood fluke Schistosoma mansoni, a major etiologic agent of human intestinal schistosomiasis. Our data show that mitogenomes from African and Neotropical Biomphalaria are highly conserved. With respect to rDNA, the two internal transcribed spacers (ITS1 and 2) were found to be highly variable whereas the three ribosomal RNA genes (28S, 5.8S and 18S rRNA) exhibited no or very limited variation. Our analyses reveal that the two taxa inhabiting Lake Victoria, B. sudanica and B. choanomphala, are very similar to one another relative to the similarity either shows to B. pfeifferi or B. glabrata. This new sequence information may prove useful for developing new markers for snail identification, environmental detection/monitoring purposes or for tracking epidemiology and snail dependencies of S. mansoni in endemic areas. It also provides new information pertinent to still unresolved questions in Biomphalaria systematics and nomenclature.
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Affiliation(s)
- Si-Ming Zhang
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerqu, NM, 87131, USA.
| | - Lijing Bu
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerqu, NM, 87131, USA
| | - Martina R Laidemitt
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerqu, NM, 87131, USA
| | - Lijun Lu
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerqu, NM, 87131, USA
| | - Martin W Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box, 54840-00200, Nairobi, Kenya
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), P.O Box, 54840-00200, Nairobi, Kenya
| | - Eric S Loker
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerqu, NM, 87131, USA.,Parasitology Division, Museum of Southwestern Biology, University of New Mexico, Albuquerque, 87131, USA
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24
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Gurarie D, Lo NC, Ndeffo-Mbah ML, Durham DP, King CH. The human-snail transmission environment shapes long term schistosomiasis control outcomes: Implications for improving the accuracy of predictive modeling. PLoS Negl Trop Dis 2018; 12:e0006514. [PMID: 29782500 PMCID: PMC5983867 DOI: 10.1371/journal.pntd.0006514] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 06/01/2018] [Accepted: 05/09/2018] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Schistosomiasis is a chronic parasitic trematode disease that affects over 240 million people worldwide. The Schistosoma lifecycle is complex, involving transmission via specific intermediate-host freshwater snails. Predictive mathematical models of Schistosoma transmission have often chosen to simplify or ignore the details of environmental human-snail interaction in their analyses. Schistosome transmission models now aim to provide better precision for policy planning of elimination of transmission. This heightens the importance of including the environmental complexity of vector-pathogen interaction in order to make more accurate projections. METHODOLOGY AND PRINCIPAL FINDINGS We propose a nonlinear snail force of infection (FOI) that takes into account an intermediate larval stage (miracidium) and snail biology. We focused, in particular, on the effects of snail force of infection (FOI) on the impact of mass drug administration (MDA) in human communities. The proposed (modified) model was compared to a conventional model in terms of their predictions. A longitudinal dataset generated in Kenya field studies was used for model calibration and validation. For each sample community, we calibrated modified and conventional model systems, then used them to model outcomes for a range of MDA regimens. In most cases, the modified model predicted more vigorous post-MDA rebound, with faster relapse to baseline levels of infection. The effect was pronounced in higher risk communities. When compared to observed data, only the modified system was able to successfully predict persistent rebound of Schistosoma infection. CONCLUSION AND SIGNIFICANCE The observed impact of varying location-specific snail inputs sheds light on the diverse MDA response patterns noted in operational research on schistosomiasis control, such as the recent SCORE project. Efficiency of human-to-snail transmission is likely to be much higher than predicted by standard models, which, in practice, will make local elimination by implementation of MDA alone highly unlikely, even over a multi-decade period.
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Affiliation(s)
- David Gurarie
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
| | - Nathan C Lo
- Division of Epidemiology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Martial L Ndeffo-Mbah
- Yale School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - David P Durham
- Yale School of Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Charles H King
- Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
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