Wilmette becomes latest Chicago suburb to collect West Nile-positive mosquitoes this year

The North Shore suburb of Wilmette this week became the latest Chicago-area municipality to discover mosquitoes carrying the West Nile virus this year.

The North Shore Mosquito Abatement District reported that a batch of mosquitoes collected in a trap in Wilmette Sunday tested positive for West Nile the following day.

In the north suburbs under the jurisdiction of the North Shore Mosquito Abatement District, West Nile-positive mosquitoes have already been found in traps in Evanston and Northbrook, the district said.

The State of Illinois reports that so far this year, a total of 28 West Nile-positive mosquito samples have been collected in Cook County. A total of 74 such samples  been collected statewide.

There have not yet been any human cases of West Nile, or positive West Nile cases in birds or other animals, in Illinois this year.

West Nile virus is spread to humans through bites from mosquitoes that have contracted the virus by feeding on infected birds.

Most cases of West Nile virus in humans are either mild, or show no symptoms, meaning many cases go unreported. Eight out of 10 people infected do not develop symptoms, according to the Centers for Disease Control and Prevention.

The worst year in Illinois for West Nile was 2002, when there were 884 human cases across the state, and 67 deaths — 42 of them in Cook County.