Ecology and Epidemiology of Crimean-Congo Hemorrhagic Fever Virus Transmission inthe Republic of Senegal

摘要

Progress continued during the fourth year of studies on the ecology of tick-borneCrimean-Congo hemorrhagic fever (CCHF) virus in the West African savannah. Prospective observations of tick and virus activity were maintained in northern Senegal to describe the seasonal activity of vector ticks. Adult tick abundance was low relative to previous years; seroconversion of sheep was correspondingly diminished. Immature ticks on small mammals and birds were most abundant during and after the rainy season. Laboratory studies of immature Hyalomma truncatum and H. marginatum rufipes feeding on various native vertebrate hosts demonstrated that the dropoff pattern ( '-host' or '3-host' ) depended on the host. Transmission studies have shown that adult male H. truncatum inoculated with CCHF virus transmitted virus to females during mating and cofeeding. Survival of uninfected, unfed adult ticks, monitored during more than one year, depended on temperature and humidity. In other studies, laboratory mice inoculated with CCHF virus differed in survival, viremia, and antibody depending on route, age titer of injection. CCHF virus was isolated from Boophilus decoloratus.