CHICAGO, May 24 (UPI) -- Illinois public health officials Friday confirmed that a crow found dead in the Chicago suburb of LaGrange tested positive for West Nile virus.
The bird was the third found in the area this month testing positive for the deadly virus that can cause fatal encephalitis in humans.
State Public Health Director Dr. John Lumpkin said the latest infected bird was found May 15.
The virus first appeared in New York in 1999 and has since been detected in 28 states, as far west as Iowa, Louisiana and Missouri.
This year, viral activity has been identified in Florida, Louisiana, New York, Pennsylvania and Virginia, as well as Illinois. It also has been detected in Alabama, Arkansas, Connecticut, the District of Columbia, Georgia, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, Mississippi, New Hampshire, North Carolina, Ohio, Rhode Island, Tennessee and Wisconsin.
The disease first turned up in Illinois last September when two dead crows from the Chicago area tested positive. In all, 138 infected birds have been found in the Chicago metropolitan area and in downstate Crawford County. No human cases have yet been reported in the state.
West Nile virus has been blamed for 149 cases of encephalitis in the United States in the past three years, mostly in the New York area. Eighteen cases have been fatal.
The disease also poses a threat to horses and other animals. It was first isolated in Uganda in 1937 and has been reported elsewhere in Africa as well as the Middle East, west and central Asia and Oceania.