O'nyong-nyong fever: An epidemic virus disease in East Africa VIII. Virus isolations from anopheles mosquitoes

Abstract

Mosquitoes and bed-bugs were collected in 1959–1960 from places in Uganda and Kenya affected by the o'nyong-nyong epidemic. Tests indicated that 39 of 144 pools containing 5,784 Anopheles funestus, and 15 of 206 pools of 6,933 A. gambiae contained o'nyong-nyong (ONN) virus. No isolation was made from 60 pools containing 1,837 culicine mosquitoes of at least 15 species, or from 13 pools of more than 1,561 bed-bugs. Infected A. funestus and A. gambiae caught in the field maintained ONN virus for at least 20 and 13 days respectively, but limited transmission trials with monkeys and infant mice, through these mosquitoes, were unsuccessful. Transmission was, however, obtained with laboratory-infected mosquitoes of both species. The findings strongly support the conclusions of previous studies in the field that A. funestus was the vector of ONN virus, and that A. gambiae was also involved.