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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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Spaan JM, Leavitt N, Shen J, Bundy T, Burrows L, Ingram C, Maehara TR, Ndungu I, Mutuku M, Owino G, Odiere M, Steinauer ML. Genotypic-specific heat shock response of vector susceptibility to Schistosoma mansoni. Ecosphere 2022; 13:e4207. [PMID: 36590709 PMCID: PMC9797131 DOI: 10.1002/ecs2.4207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/27/2022] [Indexed: 01/05/2023] Open
Abstract
Living organisms are vulnerable to thermal stress which causes a diversity of physiological outcomes. Previous work has shown that the snail vectors (Biomphalaria glabrata) of an important human pathogen, Schistosoma mansoni, revert from resistant to susceptible after short exposure to a heat stress as low as 31oC; however, due to lack of replicability among labs and genetic lines of snails, it has been hypothesized that this effect is genotype dependent. We examined the effects of heat shock on resistance of two species of snail vectors including B. glabrata and B. sudanica. We used 3 different inbred laboratory snail lines in addition to the F1 generation of field collected snails from Lake Victoria, Kenya, an area with high levels of schistosomiasis transmission. Our results showed marginal effects of heat shock on prevalence of infection in B. glabrata, and that this response was genotype specific. We found no evidence of a heat shock effect on prevalence of infection in B. sudanica or on intensity of infection (number of infectious stages shed) in either snail species. Such environmentally influenced defense responses stress the importance of considering this unique interaction between snail and parasite genotypes in determining infection dynamics under climate changes.
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Affiliation(s)
- Johannie M. Spaan
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Nathaniel Leavitt
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Jessica Shen
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Taylor Bundy
- Department of Medicine, Oregon Health and Science University, Portland, Oregon 97239
| | - Lillian Burrows
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Christopher Ingram
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Thomas R. Maehara
- M.D. School of Medicine, Western Michigan University Home Stryker, Kalamazoo, Michigan 49001
| | - Ibrahim Ndungu
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Martin Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - George Owino
- Neglected Tropical Diseases Unit, Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Maurice Odiere
- Neglected Tropical Diseases Unit, Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Michelle L. Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
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