West Nile Q&A

Q. What is West Nile virus infection?

A. It is caused by West Nile virus (WNV), which is spread to people by the bite of a mosquito infected with the virus. It's usually considered a virus of birds, but people can be accidental hosts. In people, the disease usually causes only a mild illness, but may cause encephalitis (swelling of the brain), meningitis (swelling of the lining of the brain), or even death in rare cases. The virus is named after the West Nile region of Uganda, where the virus was first identified.