Figure 2.

The life cycle of the RVF virus in Egypt and the role of the mosquito vectors. There are two transmission cycles for RVFV in nature: (1) an enzootic cycle that can occur during the normal rainfall and involves the Aedes mosquitoes, which transmit the virus vertically to their offsprings, and (2) an epidemic-epizootic cycle that occurs during abnormally heavy rainfall and flooding of dams or during the warm season. The virus is transmitted transovarially and the Culex mosquitoes distribute the virus and induce the emergence of outbreaks. The transmission of the virus to humans occurs by direct contact with infected animals. The continuous line represents the direct transmission, while the dashed line represents the vertical transmission.