West Nile encephalitis /west nīl/ [West Nile River valley and region in northern Uganda, where the disease was first observed in 1937] , a mild, febrile, sporadic disease caused by the West Nile virus, transmitted by Culex mosquitoes and occurring chiefly in the summer; infection often does not lead to encephalitis. It may be of sudden onset, and symptoms may include drowsiness, severe frontal headache, maculopapular rash, abdominal pain, loss of appetite, nausea, and generalized lymphadenopathy. Most people infected with West Nile encephalitis are asymptomatic or experience flulike symptoms. Care is supportive. Many recover quickly but may experience prolonged malaise. Also called West Nile fever.
