The first positive cases of West Nile virus in mosquitoes were recently discovered in Chicago, including in a trap near 95th Street and Ashland Avenue.

In a mass email on July 13, 19th Ward Ald. Matt O’Shea informed constituents of the situation, and he said the Chicago Department of Public Health (CDPH) confirmed the findings.

“CDPH will continue to monitor the areas where mosquitoes have tested positive,” O’Shea said, “and take appropriate precautions following additional tests.”

No human cases of West Nile virus have been reported this year, O’Shea said.

A Chicago resident died of the virus in October 2020.

According to the Centers for Disease Control and Prevention, West Nile virus is the leading cause of mosquito-borne disease in the continental United States and is most commonly spread to people through the bite of an infected mosquito.

Infections occur during mosquito season, which begins in the summer and continues through the fall.

Most infected people do not feel sick, but about 1 in 5 of infected people develop a fever and other symptoms; about 1 of every 150 infected people develop a serious, sometimes fatal, illness.

No vaccines or medications are available for West Nile virus.

The CDC advises people to use insect repellent and wear long-sleeved shirts and long pants to prevent mosquito bites.

O’Shea said the CDPH monitors up to 83 mosquito traps throughout the city and tests them on a week basis. Catch basins are treated with larvicide to kill developing mosquitoes.

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