Anopheles nili as the main vector of human malaria in villages of southern Cameroon.

In villages near Sanaga river, in the forest zone of south Cameroon, Anopheles nili Theobald is the main species of mosquito regularly found biting man inside houses. Its densities are related to the flow level of the river. It is also the main malaria vector in terms of intensity and seasonal duration of transmission. The yearly malaria inoculation rate due to An. nili alone is 104 infective bites/man, varying between 3 infective bites/man in October and 20 in March. Anopheles gambiae Giles is a less important vector in the area but reached its peak in the dry season, when the Sanaga river is at its lowest level. These observations underline the influence of local ecology on malaria transmission and the need for entomological studies in each situation.