Isolation and Genetic Characterization of Rift Valley fever virus from Aedes vexans arabiensis, Kingdom of Saudi Arabia

An outbreak of Rift Valley fever in the Kingdom of Saudi Arabia and Yemen in 2000 was the first recognized occurrence of the illness outside of Africa and Madagascar.An assessment of potential mosquito vectors in the region yielded an isolate from Aedes vexans arabiensis, most closely related to strains from Madagascar (1991) and Kenya (1997).n September 10, 2000, accounts of unexplained hemorrhagic fever in humans and associated illness in livestock along the southwestern border of Saudi Arabia and neighboring Yemen were reported to the Ministry of Health, Kingdom of Saudi Arabia.On September 15, 2000, the Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, confirmed a diagnosis of Rift Valley fever in serum samples submitted by the Ministry of Health.This confirmation marked the first occurrence of Rift Valley fever outside of Africa (1).Rift Valley fever virus (RVFV) is an important veterinary pathogen in Africa causing abortions and deaths in young animals, primarily goats and sheep (2).This mosquito-borne virus can also infect humans by arthropod blood-feeding or by contact with infected animal fluids and tissues.RVFV infection in humans is generally not apparent or is self-limiting; serious complications including hemorrhagic fever, encephalitis, and retinitis can occur.Vector-borne virus transmission in Africa is generally associated with periodic heavy rainfall during epizootics and attendant human infections (2).We conducted an entomologic investigation in the Asir, Jizan, and Makkah Regions, north of the suspected origin of the outbreak in Jizan, and in neighboring Yemen.Because this outbreak in the Arabian Peninsula was the first recorded outside of Africa, we wanted to determine the potential arthropod vectors and their larval habitats.A review of recent human