Status Quo and Future Perspectives of Molecular and Genomic Studies on the Genus Biomphalaria—The Intermediate Snail Host of Schistosoma mansoni

Abstract

Schistosomiasis, or also generally known as bilharzia or snail fever, is a parasitic disease that is caused by trematode flatworms of the genus Schistosoma. It is considered by the World Health Organisation as the second most prevalent parasitic disease after malaria and affects more than 230 million people in over 70 countries. People are infected via a variety of activities ranging from agricultural, domestic, occupational to recreational activities, where the freshwater snails Biomphalaria release Schistosoma cercariae larvae that penetrate the skin of humans when exposed in water. Understanding the biology of the intermediate host snail Biomphalaria is thus important to reveal the potential spread of schistosomiasis. In this article, we present an overview of the latest molecular studies focused on the snail Biomphalaria, including its ecology, evolution, and immune response; and propose using genomics as a foundation to further understand and control this disease vector and thus the transmission of schistosomiasis.

Seasonal patterns of Schistosoma mansoni infection within Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria

“…The former suggests that the snail host's resistance and susceptibility status play a significant role in determining whether infection is successful, as vulnerable individuals lack the ability to recognise the parasite upon entry or produce an effective immunological response in time [75]. Previous research has shown differences in immune-related genes between compatible and incompatible snails, supporting this hypothesis [76]. Conversely, the latter hypothesis proposes that the success or failure of an infection is not determined by the susceptibility or resistance of an individual, but rather by the level of compatibility between the host and parasite phenotypes, suggesting all snails are potentially susceptible to infection if they encounter a schistosome with a matching phenotype [77,78].…”

“…Conversely, the latter hypothesis proposes that the success or failure of an infection is not determined by the susceptibility or resistance of an individual, but rather by the level of compatibility between the host and parasite phenotypes, suggesting all snails are potentially susceptible to infection if they encounter a schistosome with a matching phenotype [77,78]. Previous experimental treatments have supported this hypothesis, by showing infection rates increase when the phenotypic diversity of miracidia increases [76]. Of the two hypotheses suggested, our results support the assertions proposed by the matching hypothesis, as we found the prevalence of infection increased alongside snail host genetic diversity.…”

Insights into the epidemiology, pathogenesis, and differential diagnosis of schistosomiasis

“…Molecular analysis has identified hybrid schistosomes, which are new hybrid species resulting from the hybridization of different Schistosoma species [ 79 ]. The intermediate host for S. mansoni is the freshwater snail of the genus Biomphalaria [ 14 ]. Reservoirs include primates, marsupials, and rodents.…”

A haplotype-like, chromosome-level assembled and annotated genome of Biomphalaria glabrata, an important intermediate host of schistosomiasis and the best studied model of schistosomiasis vector snails

“…Within the gastropod genus Biomphalaria , which is geographically distributed in the Old and New World, 18 species are susceptible to Schistosoma mansoni [ 12 , 13 ]. Biomphalaria glabrata has been used as a predominant model species for studies of snail-parasite interactions and schistosomiasis since the 1950s [ 14 – 17 ], accumulating a wealth of biological information [ 18 – 22 ]. B .…”