CLEVELAND (AP) - Health officials estimate that the West Nile virus may have infected as many as 83,000 people last year in Cuyahoga County, which includes Cleveland.
The county board of health released its findings Thursday.
They were based on a federally commissioned study done in December of about 1,200 residents in 19 randomly selected communities.
The infection rate among those surveyed was between 4 percent and 6.4 percent, equivalent to between 52,000 and 83,000 cases countywide.
Cuyahoga County reported 211 of Ohio's 441 confirmed cases of West Nile in 2002. Eleven of the state's 31 West Nile deaths occurred in Cuyahoga County.
The numbers reflect a fraction of those who were exposed to the virus but never were diagnosed because their symptoms were too slight to warrant medical attention, officials said.
The federal Centers for Disease Control and Prevention suggested the local study. It was the fifth such examination commissioned by the CDC in two years. The others were in New York, Louisiana and Connecticut.
West Nile symptoms include headache, fever, body aches, skin rash and swollen lymph glands. The disease is carried by mosquitos and can be fatal to birds and horses, but rarely to humans.