Species diversity and distribution of schistosome intermediate snail hosts in The Gambia.

Autor: Joof E; School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.; National Public Health Laboratories, Ministry of Health and Social Welfare, Banjul, The Gambia., Sanneh B; National Public Health Laboratories, Ministry of Health and Social Welfare, Banjul, The Gambia., Sambou SM; Epidemiology and Disease Control Department, Ministry of Health and Social Welfare, Banjul, The Gambia., Wade CM; School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.
Jazyk: angličtina
Zdroj: PLoS neglected tropical diseases [PLoS Negl Trop Dis] 2021 Oct 04; Vol. 15 (10), pp. e0009823. Date of Electronic Publication: 2021 Oct 04 (Print Publication: 2021).
DOI: 10.1371/journal.pntd.0009823
Abstrakt: There is a need for recent information on intermediate snail hosts of schistosomes in The Gambia; the previous studies were conducted over three decades ago. This study assessed the incidence, species diversity, distribution and infection status of schistosome intermediate snail hosts in the country. Malacological surveys were conducted in all 5 regions of The Gambia: Central River Region (CRR), Upper River Region (URR), Western Region (WR), Lower River Region (LRR) and North Bank Region (NBR). Sampling of snails was undertaken at 114 sites that included permanent water bodies such as streams (bolongs), rice fields, irrigation canals and swamps; and temporal (seasonal) laterite pools. Ecological and physicochemical factors of sites were recorded. Snails were identified morphologically and screened for schistosome infections using molecular techniques. Freshwater snails were found at more than 50% (60/114) of sites sampled. While three species of Bulinus were collected, no Biomphalaria snails were found in any of the sites sampled. Of the total 2877 Bulinus snails collected, 75.9% were identified as Bulinus senegalensis, 20.9% as Bulinus forskalii and 3.2% as Bulinus truncatus. Seasonal pools produced the largest number of snails, and CRR was the region with the largest number of snails. Bulinus senegalensis was found more in seasonal pools as opposed to permanent sites, where B. forskalii and B. truncatus were observed to thrive. Bulinus snails were more common in seasonal sites where aquatic vegetation was present. In permanent sites, the abundance of snails increased with increase in water temperature and decrease in water pH. Bulinus senegalensis was found infected with both S. haematobium and S. bovis, while B. forskalii and B. truncatus had only S. bovis infection. While the human parasite S. haematobium was restricted to just four sites, the livestock parasite S. bovis had a much more widespread geographical distribution across both CRR and URR. This new information on the distribution of intermediate snail hosts of schistosomes in The Gambia will be vital for the national schistosomiasis control initiative.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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