ATLANTA -- The number of West Nile infections this year is nearly double the amount from this time last year, but fewer people have died as a result, federal officials said Thursday.
So far this year, 2,923 people have been infected with the virus and 54 have died. Last year at this time, there were 1,641 human cases and 72 deaths, the Centers for Disease Control and Prevention said.
"We are still experiencing the up side of the epidemic curve," said Dr. Julie Gerberding, CDC director.
Late August through September is considered the peak season for the virus, which is spread by mosquitoes. By the end of 2002, 4,156 people were infected and 284 died in the largest West Nile outbreak in the Western Hemisphere.
Gerberding said the higher number of infections this year may be the result of improved testing methods and earlier testing. She did not explain the lower death rate, but health officials have said this year's reported cases tend to be less severe, in part because people with milder symptoms are more likely to be tested.
Colorado has been the hardest hit this summer, with 973 human cases. Thirteen of the country's deaths were in Colorado, followed by 10 in Nebraska.
Nebraska had the second-highest number of West Nile cases, with 436, followed by 407 in South Dakota, 239 in Wyoming and 190 in Texas, the CDC said.
The agency's count may be lower than state figures, however, as there often is a lag time of case reporting between the states and the CDC. In previous years, the CDC handled most of the West Nile testing, but state health departments and commercial labs are now able to test for infections.
In the continental United States, only Nevada and Oregon have yet to report cases of West Nile. The virus rarely kills, and most who become infected have no symptoms. About one in 150 people infected will become seriously ill, with the worst cases developing potentially deadly encephalitis or meningitis.
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