Picture of West Nile Virus
West Nile fever:A febrile disease caused by theWest Nile virus从鸟类传播到the common Culex mosquito and then to people. The virus is named after the area it was first found in Uganda.
West Nile feveroccurs in parts of Africa and Asia and, infrequently, in Southern Europe and the Middle East. TheWest Nile virushad never been seen in birds or people in the Western Hemisphere prior to an outbreak in the summer of 1999 in New York City.
> The virus has since moved across the United States.Signs and symptoms include the sudden onset of drowsiness,headacheandnauseadue toencephalitis,painin the abdomen, arash, and swollen glands (lymphadenopathy). These features are usually but not always mild. Fatal cases tend to involve infants and small children under age 5, the aged, and people with an impaired immune system.
The outbreak in New York, which was entirely unexpected, reflects the reality of global travel today that can transport exoticvirusesto new areas. If a mosquito-borne virus enters a new area, the entire mosquito population may be susceptible, putting everyone living there at risk.
West Nilefeveris also known asWest Nile encephalitis. The virus is closely related to other flaviviruses including those responsible forSt. Louis encephalitis, Japaneseencephalitisand Murray Valley encephalitis.