title: On the distribution of schistosome infections among host snails.
abstract: The distribution of Schistosoma haematobium infections in a population of Bulinus globosus snails collected from a field site in Zimbabwe is described. Cercariae of both sexes emerged from a proportion of patent infected snails, as was demonstrated by the detection of paired schistosomes in hamsters each exposed to cercariae from a single snail. These snails must have been infected by two or more miracidia. Analysis showed that the proportion of mixed-sex infections was higher than expected if infections were distributed at random among snails. An index of overdispersion was calculated. Overdispersion of infections results from heterogeneities in the exposure and/or susceptibility of snails to infection. The implications for the epidemiology and control of schistosomiasis haematobium are discussed.
authors.affiliation: Department of Pure and Applied Biology, Imperial College, London SW7 2BB, U.K.
authors.forename: M E
authors.initials: ME
authors.lastname: Woolhouse
authors.forename: S K
authors.initials: SK
authors.lastname: Chandiwana
authors.forename: M
authors.initials: M
authors.lastname: Bradley
mesh_terms: D000818:Animals; D002033:Bulinus / Q000469:parasitology*; D004199:Disease Vectors; D005260:Female; D008297:Male; D012548:Schistosoma haematobium / Q000502:physiology*; D015030:Zimbabwe