Because this illness is not caused by bacteria, antibiotics do not help treat West Nile virus infection. Standard hospital care may help decrease the risk of complications in severe illness. There is no human vaccine available at present, and it is likely there will not be one for several years.

Research trials are under way to determine whether ribavirin, an antiviral drug used to treat hepatitis C, may be helpful.

In general, the likely outcome of a mild West Nile virus infection is excellent.

For patients with severe cases of West Nile virus infection, the outlook is more guarded. West Nile encephalitis or meningitis has the potential to lead to brain damage and death. Approximately 10% of patients with brain inflammation do not survive.

Complications from mild West Nile virus infection are extremely rare.

Complications from severe West Nile virus infection include permanent brain damage or muscle weakness (sometimes similar to polio), and death.

Call your health care provider if you have any of the symptoms of West Nile virus infection, particularly if you may have had contact with mosquitos. If you are severely ill, seek attention in an emergency room.

If you have been bitten by an infected mosquito, there is no treatment to avoid development of West Nile virus infection. People in good general health generally do not develop a serious illness even if bitten by an infected mosquito.