"Only one of every five people who are bitten by an infected mosquito develop any kind of symptoms, such as mild fever," Dr. Russell E. Bartt
told Reuters Health."One of 200 will develop one of the severe neurological symptoms we found to be associated with the disease." Overall, 80 percent of people who are bitten by a mosquito carrying the virus will have no symptoms at all and simply develop an immunity, said Bartt, an assistant professor of neurological sciences at Rush-Presbyterian-St.Luke's Hospital
in Chicago and a senior attending physician at Cook County Hospital
Elderly people and those with compromised immune systems are most vulnerable to severe disease, he
said.In the study, lead investigator Dr. Nidhi K. Watson, Bartt and their colleagues reviewed the records of several Chicago hospitals to identify people who had West Nile virus and had been seen for health problems.
As summer approaches and the risk of West Nile virus infections increase, Bartt
said that people should make sure that standing water -- a breeding ground for mosquitoes -- is not allowed to collect near their homes.Typical culprits would be old tires, garbage containers without lids, and gutters.
"If you're planning a barbecue at sunset, or a picnic in a shady area, wear long sleeves and insect repellant," he
told Reuters Health.
There were 4,161 human cases of West Nile in the United States last year, including 277 deaths, according to the CDC's
Web site.The outbreak was the largest since the virus struck the United States more than three years ago.
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