West Nile virus found in Forreston, Ogle County reports

The Ogle County Health Department has confirmed the first mosquito pool with West Nile virus found in the county this year.

A mosquito pool in Forreston tested positive for West Nile virus, according to an OCHD news release Tuesday. Mosquitoes with the virus should be assumed to be present throughout the county.

Ogle now joins 44 counties in Illinois where people, birds, mosquitoes or horses have tested positive, according to the Illinois Department of Public Health. That list does not include Lee, Whiteside or Carroll counties. Three cases in humans have been confirmed so far this year in Illinois – in DuPage and Lake counties in the suburbs and Wayne County downstate.

Mosquitoes will be present through the fall, so it is important to take precautions to prevent West Nile virus in humans, the health department advised. Monitoring for West Nile virus in Illinois for 2025 includes laboratory tests for mosquito batches as well as testing humans with West Nile virus-like symptoms.

West Nile virus is transmitted through the bite of a Culex pipiens 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. Symptoms may last from a few days to a few weeks. However, four out of five people infected with West Nile virus will not show any symptoms, according to the release.

In rare cases, severe illness, including meningitis or encephalitis, and even death can occur. People older than 50 and those with weakened immune systems are at higher risk for severe illness from West Nile virus.

Precautions include practicing the three “R’s” – reduce, repel and report.

Reduce: Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears or other openings. Try to keep doors and windows shut. Eliminate, or refresh each week, all sources of standing water where mosquitoes can breed, including water in bird baths, ponds, flowerpots, wading pools, old tires and any other containers.

Repel: When outdoors, wear shoes and socks, long pants and a long-sleeved shirt, and apply insect repellent that contains DEET, picaridin, oil of lemon eucalyptus or IR 3535, according to label instructions. Consult a physician before using repellents on infants.

Report: Report locations where you see water sitting stagnant for more than a week, such as roadside ditches, flooded yards and similar locations that may produce mosquitoes. The local health department or city government may be able to add larvicide to the water, which will kill any mosquito eggs.

To learn more about West Nile virus and other mosquito-borne diseases and prevention methods, consult the Illinois Department of Public Health website or contact the IDPH hotline at 866-369-9710 from 8 a.m. to 5 p.m. Monday through Friday.