Microhabitat preferences of Biomphalaria pfeifferi and Lymnaeanatalensis in a natural and a man-made habitat in Southeastern Tanzania

Memórias do Instituto Oswaldo Cruz

Jürg Utzinger¹  Marcel Tanner² 

[1] ,Swiss Tropical Institute Department of Public Health and Epidemiology Basel,Switzerland

关键词: Biomphalaria pfeifferi;    Lymnaea natalensis;    man;    made habitat;    microhabitat preferences;    removal collecting;    schistosomiasis;    Tanzania;   

DOI  :  10.1590/S0074-02762000000300002

来源: SciELO

【 摘 要 】

Schistosoma mansoni is an important human parasitic diseasewhich is widespread throughout Africa. As Biomphalaria pfeifferi snails act asintermediate host, knowledge of their population ecology is an essential prerequisitetowards understanding disease transmission. We conducted a field study and assessed thedensity and microhabitat preferences of B.pfeifferi in a natural habitatwhich was a residual pool of a river. Repeated removal collecting revealed a density of26.6 [95% confidence interval (CI): 24.9-28.3] snails/m2. B.pfeifferishowed microhabitat preferences for shallow water (depths: 0-4cm). They were foundmost abundantly close to the shoreline (distances: 0-40cm), and preferred eitherplant detritus or bedrock as substratum. Lymnaea natalensis, a snail which may actas a host for human Fasciola gigantica, also occurred in this habitat with adensity of 34.0 (95% CI: 24.7-43.3) snails/m2, and preferred significantlydifferent microhabitats when compared to B.pfeifferi. Microhabitat selectionby these snail species was also investigated in a man-made habitat nearby, which consistedof a flat layer of concrete fixed on the riverbed, covered by algae. Here, B.pfeifferishowed no preference for locations close to the shoreline, probably because the habitathad a uniform depth. We conclude that repeated removal collecting in shallow habitatsprovides reliable estimates of snail densities and that habitat changes throughconstructions may create favourable microhabitats and contribute to additional diseasetransmission.

【 授权许可】

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