The dynamics of Anopheles arabiensis Patton and Anopheles funestus Giles larval densities in relation to small-scale rice cultivation practices in Western Kenya

Abstract

A two-year study was conducted on the densities of Anopheles arabiensis Patton and Anopheles funestus Giles larvae in two rice cultivation sites with divergent farming practices, at the Ahero Irrigation Scheme, Kenya. The study site was situated in a malaria endemic area where An. arabiensis and An. funestus are the principal vectors. Sampling of mosquito larvae and predators was carried out fortnightly from selected rice paddies, nurseries and irrigation canals. The results of the study showed a relationship between the farming practices and the breeding of the two mosquito species. There were distinct differences in the stability of breeding sites, vegetation heights, and water depths, due to the differences in cultivation practices. The associated larval density fluctuations and the temporo-spatial distribution of the two malaria vectors showed that certain practices can affect the level of breeding of the two vector species as well as lead to the exclusion of An. funestus.