First recorded outbreak of XXXX in Kenya, 1992-1993. II. Entomologic investigations.

@entity1 @entity22073 @entity6599 @entity3176
The first recorded outbreak of @entity22073 in Kenya occurred from mid-1992 through March 1993 in the south Kerio Valley, Rift Valley Province. We conducted entomologic studies in February-March 1993 to identify the likely vectors and determine the potential for transmission in the surrounding rural and urban areas. Mosquitoes were collected by landing capture and processed for virus isolation. Container surveys were conducted around @entity1 habitation. Transmission was mainly in woodland of varying density, at altitudes of 1,300-1,800 m. The abundance of Aedes africanus in this biotope, and two isolations of virus from pools of this species, suggest that it was the principal vector in the main period of the outbreak. A third isolate was made from a pool of Ae. keniensis, a little-known species that was collected in the same biotope. Other known @entity22073 vectors that were collected in the arid parts of the valley may have been involved at an earlier stage of the epidemic. @entity3176 and @entity6599 were present in the outbreak area. Peridomestic mosquito species were absent but abundant at urban sites outside the outbreak area. The entomologic and epidemiologic evidence indicate that this was a sylvatic outbreak in which @entity1 cases were directly linked to the epizootic and were independent of other @entity1 cases. The region of the Kerio Valley is probably subject to recurrent wandering epizootics of @entity22073 , although previous episodes of scattered @entity1 infection have gone unrecorded. The risk that the disease could emerge as an urban problem in Kenya should not be ignored.
