Each year, the health department's Mosquito Control program collects mosquitoes to test for the virus.

Mosquitoes have tested positive for the virus in Benton, Hamilton, Jennings and Marion counties.

Health officials earlier reported cases in Huntington County near Fort Wayne and central Indiana's Madison County.

The Marion County Public Health Department has documented the first mosquitoes of the season carrying West Nile virus. No human cases of the virus have been reported this year in Marion County.