Twelve isolations of Zika virus from Aedes (Stegomyia) africanus

Abstract

In continuation of a series of studies of arboreal mosquitos as virus vectors in Uganda, 12 strains of Zika virus and one strain of another Group B arbovirus were isolated between November 1961 and June 1963 from pools of Aedes (Stegomyia) africanus caught on a 120-foot (36.5-m) tower in Zika forest. For five strains it is known at what height the mosquitos were caught: one was from mosquitos taken at ground level, and the other four were from mosquitos taken in or above the upper canopy after sunset. No small mammal trapped in the forest either on the ground or in the trees showed serum antibody for Zika virus.These findings suggest that in Zika forest, A. (S.) africanus becomes infected from a virus reservoir that is probably not among the small animals tested and that infected mosquitos are liable to be spread widely beyond the forest by convection currents above the tree-tops in the first two or three hours after sunset.