Associated Press - November 6, 2009 12:25 PM ET

CHEYENNE, Wyo. (AP) - The Wyoming Department of Health reports that 12 Wyoming residents were infected by West Nile virus this year, resulting in one death and three hospitalizations.

The department said Friday that the laboratory-confirmed cases included four in Fremont County, three in Goshen County, two in Platte County, and one each from Converse, Campbell and Washakie counties.

Mosquitoes spread the virus when they feed on infected birds and then bite people or other animals. Most people never develop symptoms, but extreme cases can result in meningitis or encephalitis.

Last year, there were 10 West Nile cases and no deaths. But this year's numbers were much lower than some previous years this decade. In 2003, the department recorded 393 human cases and 9 deaths.

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