The West Nile fever is transmitted by mosquitoes carrying the West Nile virus; it is endemic to regions of Africa, Asia, and Europe. Symptoms include headache, fever, gastrointestinal symptoms; and swollen and enlarged lymph nodes. Meningitis, encephalitis and myelitis may also occur. The disease may occasionally be fatal or leave survivors with permanent neurological deficits. There is no vaccine against West Nile fever and treatment is purely supportive.