Stanford Internal Medicine (SIM)

SIM 2004 West Nile Virus Update

West Nile Virus is a mosquito-borne virus which can be trasnmitted to animals and humans. The great majority of humans who contract this disease will never be aware of being ill and the virus will cause no lasting effect. A very small minority of humans who contract the disease, however, can develop a more severe form of the disease, characterized by fever, weakness, gastrointestinal symptoms, headache, and changes in mental status. Studies in New York City in 2002-3 found that approximately one person in 150 who contract the disease might develop the more severe symptoms, the majority of these are those over 50 years of age, especially those who have other chronic medical conditions. Treatment is supportive, providing medications to control the symptoms and keeping the patient comfortable until the disease has resolved. Of those admitted to the hospital with severe symptoms, from 3-14% may die from the disease. Again, those most severely affected are of advanced age and who have other serious medical conditions. The virus initially entered California in 2003, it has now spread to Northern California in 2004. The best defense is prevention - avoiding mesquitos thorugh the application of repellants and limiting exposure by wearing appropriate clothing and avoiding evening exposure. In addition, the community can markedly decrease the risk of disease by reducing standing water and through the application of mosquito-control programs.

Please should contact your physician at SIM if you have any questions or have the following symptoms:

West Nile Virus Educational Resources

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