Mosquitoes In Skokie First To Test Positive For West Nile Virus

NORTHFIELD, IL — A batch of mosquitoes from Skokie was the first in the state to test positive for West Nile virus this year. While no human infections have been reported so far in 2021, public health officials are still warning residents to be cautious.

The North Shore Mosquito Abatement District collected the insects June 9 from a mosquito trap in Skokie. Further testing revealed the disease on June 11. The risk of being infected during this time of year is low, since temperatures are high and there is little rainfall, though preventative measures like using bug spray and avoiding standing water can lower risk even further.

The NSMAD recommends strategies on its website such as wearing loose-fitting clothing and avoiding being outdoors at dawn and dusk, as those are prime mosquito hours. The most common breeding place for mosquitoes are small bodies of still, unmoving water. Both the Illinois Department of Public Health and NSMAD stressed the importance of refreshing water sources and checking old tires, flower pots and any other place where water may become warm and stagnant.

"Remember," district officials always say, "if it can hold water, it can breed mosquitoes."

Scientists monitor an area for West Nile virus by gathering any dead crows, blue jays, robins and other perching birds for testing along with any larger samples such as sick horses and humans. If one of the subjects tests positive for the virus, officials will know an infected batch is nearby. Local health departments urge people to report instances of sick or dead birds during the summer months.

The first mosquitoes to test positive for West Nile virus in 2020 were collected in late May in Naperville. Last year, 26 counties in Illinois reported a West Nile virus-positive mosquito batch, bird or human case, officials said. While West Nile cases are normally underreported because the rare symptoms mimic the flu, the IDPH still reported 39 human cases including four deaths.

"We are starting to see West Nile virus make its annual appearance," said Illinois Department of Public Health Director Dr. Ngozi Ezike. "Remember to take precautions to protect yourself from mosquitoes and the viruses they carry."

West Nile virus is transmitted through the bite of a specific mosquito, commonly called a house mosquito, that has picked up the virus by feeding on an infected bird. Common symptoms include fever, nausea, headache and muscle aches. However, four out of five people infected with West Nile virus will not show any symptoms. As with most viruses, those with weakened immune systems are at higher risk of severe cases.

Reporting suspicious bird deaths and keeping screens and doors shut tight are the most effective methods of prevention. When someone must go outdoors during peak mosquito times, officials say, it is best to apply an EPA-registered insect repellent that contains DEET, picaridin, lemon or eucalyptus oil.