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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Mosquito and Fly Research » Research » Publications at this Location » Publication #221352

Title: Predicting the Next Outbreak of Rift Valley Fever (RVF)

item Linthicum, Kenneth - Ken
item Gibson, Seth

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/18/2007
Publication Date: 10/18/2007
Citation: Linthicum, K., Anyamba, A., Small, J., Tucker, C.J., Chretien, J., Britch, S.C. 2007. Predicting the Next Outbreak of Rift Valley Fever (RVF). Presented at the 111th Annual Meeting of the United States Animal Health Association and 50th Annual Conference American Association of Veterinary Laboratory Diagnosticians in Reno, Nevada on October 18-24, 2007.

Interpretive Summary:

Technical Abstract: Rift Valley fever (RVF) is a mosquito-borne zoonotic disease of domestic ruminants in Africa. The disease is most severe in cattle, sheep, and goats, and it causes high mortality in young animals and abortion in adults. Exotic aanimal breeds from areas where RVF is not endemic tend to be more susceptible. Human infection causes significant morbidity and mortality. RVF has caused serious disease in laboratory workers and must be handled with high level biosecurity. RVF was first described in 1930 in the Rift Valley of Kenya, and the disease has since occurred irregularly in Kenya every 3 to 10 years. The disease first spread outside sub-Saharan Africa into Egypt in 1997 and resulted in large losses among the domestic animal populations and caused significant human disease. Subsequently, in 1987 a large outbreak in animals and people occurred in Sahel region of Senegal and Mauritania, and then in September 2000, a RVF outbreak occurred in Saudi Arabia and Yemen along the Red Sea Coast, representing the first Rift Valley fever cases identified outside Africa. RVF generally occurs during years of unusually heavy rainfall and when localized and widespread flooding occurs. It is thought that the flooding causes transovarially infected Aedes mosquito eggs to hatch and introduce the virus into domestic animals, thus allowing the maintenance of the virus in nature during dry non-epidemic conditions. After livestock are infected, a wide variety of mosquito species may act as the vector for transmission of RVF virus to spread the disease. There are no licensed animal or human vaccines available for use in the United States. We have developed a monitoring and risk mapping system using global sea surface temperatures and normalized difference vegetation index (NDVI) times series data derived from the advanced very high resolution radiometer (AVHRR) instrument on polar orbiting national oceanographic and atmospheric administration (NOAA) satellites to map areas at risk for a potential outbreaks in sub-Saharan Africa, the Nile River Valley, and the Arabian Peninsula. This system is now an important tool for local, national and international organizations involved in the prevention and control of animal and human disease, permitting focused and timely implementation of disease control strategies several months before an outbreak. We are currently developing a geographic information system (GIS)-based remotely sensed early warning system for potential RVF vectors in the United States. Forecasts of the potential emergence of mosquito vectors will be disseminated throughout the United States, providing several months’ warning in advance of potentially elevated mosquito populations. This would allow timely, targeted implementation of mosquito control, animal quarantine and vaccine strategies to reduce or prevent animal and human disease.