West Nile Virus Home > West Nile Encephalitis
About 1 in 150 people infected with West Nile virus will develop West Nile encephalitis. Symptoms of this condition can include disorientation, coma, convulsions, and tremors. Currently, there is no cure for this illness; however, there are medications that can help relieve some of the symptoms.
West Nile virus disease (simply known as West Nile virus or WNV) is a potentially serious illness caused by the West Nile virus. Experts believe that West Nile virus is established as a seasonal epidemic in North America; it flares up in the summer and continues into the fall.
West Nile encephalitis is a severe form of West Nile virus that occurs when the West Nile virus crosses from the blood into the brain and causes inflammation.
The West Nile virus is a flavivirus (transmitted by ticks and mosquitoes) commonly found in Africa, West Asia, and the Middle East. It is closely related to the St. Louis encephalitis virus, which is also found in the United States. The virus can infect humans, birds, mosquitoes, horses, and some other mammals.
The length of time that the West Nile virus has been in the United States is unknown, but scientists believe the virus has probably been in the eastern United States since the early summer of 1999, or possibly longer.
In most cases, West Nile virus is spread by the bite of an infected mosquito. In rare cases, the West Nile virus can be transmitted through blood transfusions, organ transplants, breastfeeding, and even during pregnancy, from mother to baby (see Cause of West Nile Virus).