Yellow fever in Western Uganda

An investigation covering a 4-year period has been made in an area in Uganda, East Africa, where preliminary protection tests indicated that yellow fever had occurred. During the 4th year of the study an epidemic of yellow fever of some magnitude occurred in the area. Virus was isolated from a human case and from wild-caught Aëdes simpsoni mosquitoes. The data obtained indicate that this outbreak in the human population was associated with contact with the forest. Once it became established in man the principal vector of the disease appeared to be the mosquito, A. simpsoni.