Cytopathic effect of Semliki Forest virus in the mosquito Aedes aegypti.

Summary The mosquito Aedes aegypti was infected with Semliki Forest virus, both by feeding on viremic mice and by the injection of virus into the hemocoele. Transmission of virus to suckling mice was demonstrable within a week after infection, but the transmission rate then declined to reach zero after three weeks, in spite of the fact that the thorax still contained large amounts of virus. The salivary glands of infected moequitoes showed cytological changes which were maximal three weeks after infection. At this time mosquitoes had some difficulty in obtaining a blood meal. The salivary gland changes included a gross decrease in the secretory regions of glandular cells, and an inability of these cells to exclude trypan blue. The salivary gland changes occurred in mosquitoes infected by feeding or by injection with high or with low doses of virus. No shortening of the life span of infected mosquitoes could be demonstrated. Attempts to study the salivary glands of infected mosquitoes by fluorescent antibody staining failed.