West Nile virus is a disease transmitted from infected birds to people by mosquitoes. Although most people who are infected only experience mild flu-like symptoms, a small number of infected individuals may develop life threatening complications such as encephalitis or meningitis (inflammation of the brain or brain lining). West Nile virus can be fatal in some cases.
Culex pipiens is one of the mosquito species that serves as a vector for the West Nile Virus
The below information is a microsite feed from the CDC West Nile website. It is updated regularly by the CDC.