Mosquitoes in St. Clair County have tested positive the West Nile virus, prompting local authorities to warn the community to take certain precautions.
The St. Clair County Health Department announced Friday, June 28, that routine testing of mosquitoes uncovered “evidence of the West Nile virus,” which can be transmitted to humans through mosquito bites. The announcement comes a few weeks after the state’s first mosquito-borne virus of 2024 -- Jamestown Canyon virus -- was confirmed in Saginaw County.
Health officials warn that about one in five people infected with West Nile virus will “develop symptoms such as headache, body aches, joint pains, and fatigue. In rare cases, WNV can lead to severe neurological complications and death, especially among older adults and individuals with weakened immune systems,” the health department said.
Symptoms of Jamestown Canyon virus include high fever, confusion, muscle weakness, headache, and fatigue. In rare cases, the virus can cause severe disease in the brain and/or spinal cord including encephalitis and meningitis.
Experts maintain that the best way to prevent illness is to prevent mosquito bites altogether.
Preventing mosquito bites
Michigan officials suggest taking the following steps to prevent mosquito bites:
- When used as directed, Environmental Protection Agency (EPA)-registered insect repellents with one of the active ingredients below are proven safe and effective, even for pregnant and breastfeeding women: DEET, Picaridin (known as KBR 3023 and icaridin outside the US), IR3535, Oil of lemon eucalyptus (OLE), Para-menthane-diol (PMD), and 2-undecanone.
- Wear light-colored, long-sleeved shirts and long pants when outdoors. Apply insect repellent to clothing to help prevent bites.
- Maintain window and door screening to help keep mosquitoes outside.
- Empty water from mosquito breeding sites around the home, such as buckets, unused kiddie pools, old tires or similar sites where mosquitoes lay eggs.
- You could also hire a mosquito control business. Mosquito control businesses are required to be licensed to apply pesticides in Michigan. A list of Michigan firms licensed to apply pesticides is available online.
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Mosquitoes lay eggs in or near standing water
Mosquitoes need standing water to reproduce. That’s why you should empty, scrub or cover any items that hold water.
Standing water is often found in old tires, buckets, planters, toys, pools, birdbaths, flower pot saucers or trash containers.
Mosquitoes can complete their life cycle in about a week. The CDC recommends using an outdoor insect spray made to kill adult mosquitoes. Mosquitoes are often found in dark, humid areas.
Can’t remove standing water? Larvicides are an option
If you’re unable to remove the standing water where you live then you’ve got one other option: Larvicides.
Larvicides work by killing mosquito larvae and pupae before they grow into pesky adults. According to the CDC, if you use larvicides correctly, they do not harm people, pets or the environment.
Larvicides come in liquids, tablets, bits, pellets, granules and briquettes. You use them by applying them where mosquitoes lay eggs (that means anywhere that holds standing water). That can include buckets and rain barrels, fountains, gutters or downspouts, non-chlorinated swimming pools, pool covers that collect water, tires and tree holes.
Use larvicides to treat standing water that will not be used for drinking and cannot be covered, dumped or removed.