WebMD Answers
West Nile encephalitis is an infection of the brain that is caused by a virus known as the West Nile virus. First identified in Uganda in 1937, the virus is commonly found in Africa, West Asia, and the Middle East. "Encephalitis" means inflammation of the brain. One of the causes of encephalitis is viral and bacterial infections, including viral infections transmitted by mosquitoes.
West Nile virus had not been previously reported in the U.S. prior to an outbreak in New York in September 1999. According to the U.S. Centers for Disease Control and Prevention (CDC), 28,961 confirmed and probable cases of West Nile virus disease were reported from 1999 to 2008.
In 41% of the cases, patients developed neuroinvasive disease (involvement of the brain and nervous system), the most severe form of West Nile virus infection. The CDC reports neuroinvasive disease was reported by 46 states and the District of Columbia (none from Alaska, Hawaii, Maine, or Vermont or any U.S. territories). Neuroinvasive disease was most prevalent in the west north central and mountain states, with 63% of cases being reported from 10 states: Arizona, California, Colorado, Illinois, Louisiana, Michigan, Mississippi, Nebraska, South Dakota, and Texas.
West Nile virus also is called West Nile fever or West Nile encephalitis.
This answer should not be considered medical advice...
This answer should not be considered medical advice and should not take the place of a doctor’s visit. Please see the bottom of the page for more information or visit our Terms and Conditions.![]()