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

Andrus, Peter S.; Stothard, J. Russell; Wade, Christopher M.

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.

Citation

Andrus, P. S., Stothard, J. R., & Wade, C. M. (2023). Seasonal patterns of Schistosoma mansoni infection within Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria. PLoS Neglected Tropical Diseases, 17(8), Article e0011506. https://doi.org/10.1371/journal.pntd.0011506

• Journal Article Type: Article
• Acceptance Date: Jul 6, 2023
• Online Publication Date: Aug 14, 2023
• Publication Date: Aug 14, 2023
• Deposit Date: Aug 21, 2023
• Publicly Available Date: Aug 22, 2023
• Journal: PLoS neglected tropical diseases
• Electronic ISSN: 1935-2735
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 17
• Issue: 8
• Article Number: e0011506
• DOI: https://doi.org/10.1371/journal.pntd.0011506
• Keywords: Biomphalaria; Schistosoma mansoni; Haplotypes; Seasons; Molting; Parasitic diseases; Schistosomiasis; Shores
• Public URL: https://nottingham-repository.worktribe.com/output/24413706
• Publisher URL: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0011506