The role of secondary vectors of malaria in North-East Tanganyika

Single sporozoite positive specimens of A. coustani, A. pharoensis and A. squamosus were found among series of dissections made in the course of a 3-year study of infection rates in outdoor biting anopheles. No infected specimens were found among large numbers of A. tenebrosus dissected. Apart from the latter species, all the others were present in relatively small numbers. It is concluded that none of them is likely to be of any importance once transmission by the main vectors has been interrupted. Their poor vectorial capacity appears to be linked with a naturally occurring high mortality rate.