Mosquitoes test positive for West Nile virus in LaSalle Co.


OTTAWA – The LaSalle County Health Department received confirmation that mosquitoes from Ottawa tested positive for West Nile virus. The mosquitoes were collected on Sept. 3 and Environmental Health staff conducted the confirmatory test on the mosquitoes at the Health Department. This is the first documented West Nile virus activity in LaSalle County this year.

Chris Pozzi, Director of Environmental Health, “This is the time of year we expect to see West Nile virus activity increase. It is important that people be conscientious about self-protection whenever they are outside during the evening hours. In hot, dry weather, mosquitoes that carry West Nile virus breed in stagnant water and multiply rapidly. The best way to protect yourself against illness is to wear insect repellent and to get rid of any stagnant water around your home to reduce the number of mosquitoes.”

West Nile virus is transmitted through the bite of a Culex pipiens mosquito, commonly called a house mosquito, which 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. In rare cases, severe illness including meningitis or encephalitis, or even death, can occur. People older than 60 and individuals with weakened immune systems are at higher risk for severe illness from West Nile virus.

Monitoring for West Nile virus includes laboratory tests for mosquito batches, dead crows, blue jays, and robins, as well as testing humans with West Nile virus-like symptoms. People who observe a sick or dying crow, blue jay, or robin should contact the health department, which will determine if the bird will be picked up for testing.

There are some simple precautions you can take to Fight the Bite. 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, pet bowls, clogged rain gutters, 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, old tires, stagnant pools, or other unattended water holding containers 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.

A complete listing of West Nile virus statistics for LaSalle County is available on the health department’s website at A state-wide listing is available at the Illinois Department of Public Health’s website