Distribution patterns and cercarial shedding of Bulinus nasutus and other snails in the Msambweni area, Coast Province, Kenya

Am J Trop Med Hyg. 2004 Apr;70(4):449-56.

Abstract

In the Msambweni area of the Kwale District in Kenya, an area endemic for Schistosoma haematobium, potential intermediate-host snails were systematically surveyed in water bodies associated with human contact that were previously surveyed in the 1980s. Bulinus (africanus) nasutus, which accounted for 67% of the snails collected, was the only snail shedding S. haematobium cercariae. Lanistes purpureus was the second most common snail (25%); lower numbers of Bulinus forskalii and Melanoides tuberculata were also recovered. Infection with non-S. haematobium trematodes was found among all snail species. Rainfall was significantly associated with the temporal distribution of all snail species: high numbers of Bulinus nasutus developed after extensive rainfall, followed, in turn, by increased S. haematobium shedding. Spatial distribution of snails was significantly clustered over a range of up to 1 km, with peak clustering observed at a distance of 400 meters. Water lily (Nymphaea spp.) and several aquatic grass species appeared necessary for local colonization by B. nasutus or L. purpureus.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bulinus / growth & development*
  • Bulinus / parasitology*
  • Cluster Analysis
  • Disease Vectors
  • Humans
  • Hydrogen-Ion Concentration
  • Kenya
  • Satellite Communications
  • Schistosoma haematobium / growth & development*
  • Schistosomiasis haematobia / parasitology
  • Schistosomiasis haematobia / transmission*
  • Water / chemistry
  • Water / parasitology*

Substances

  • Water