Chetotaxic polymorphism and development of sensillary associations in the cercaria of Schistosoma mansoni from Cameroon

A survey of the variation of the cercarial papillae patterns, in wild cameroonese samples of S. mansoni, shows ranges of values quite different from those already recorded in Africa. African chaetotype frequency is very low and American-Caribbean one relatively highest. Ecological isolation and possible interbreeding between strains of S. mansoni, transmitted by the 2 sympatric species of snail vector, would have occurred to select the third chaetotype.