Michigan weather continues to be ripe for what feels like 'biblical plague' of mosquitoes

Posted at 2:10 PM, Jul 26, 2021

ANN ARBOR (WXYZ) — Just a milligram of blood from one good bite on your arm or ankle gives a mosquito all she needs to lay hundreds of eggs at once.


"It's the female mosquitoes that bite for blood and they convert that blood into into eggs and the eggs then are laid," said Ned Walker, a professor of entomology and microbiology at Michigan State University who is also known as "the mosquito guy."

And Walker says you can feel comfort in knowing that it's not just you Michigan mosquitoes are really bugging this year.

"So it's usually about 10 to 12 days after a heavy rain event where we see the mosquito population increase. But what I was impressed with really was how how huge a reversal it was from like virtually no mosquitoes at all, to just a biblical plague of them."

"The mosquitoes somehow know where to put their eggs ahead of time before the flooding takes place, and by flooding, what I mean is the temporary formation of puddles, so in grassy areas like roadside ditches," Professor Walker said, adding low-lying meadows that you'll observe are hard to mow or yards where the water sits for about, you know, two weeks or so."

Walker says what we're largely experiencing right now are called 'Summer Floodwater' mosquitoes, and all the eggs need is a good rain (Yep! Like the one we just had) to hatch.

"And that produced this very, very large brood of adult mosquitoes, which are still biting us now," he said.

And all the eggs don't hatch at once, there are staggered hatchings. Professor Walker says those staggered hatchings lead to "some of the pulsing of the mosquito populations that we see with each rainfall, but the other ones are just new eggs that are laid by the mosquitoes that are out now."

Action News caught up to the University of Michigan's Dr. Brad Uren, an associate professor of emergency medicine who says what most people will experience is that familiar itch.

But Dr. Uren says you have to be careful that your scratching doesn't lead to further skin irritation because that could eventually cause an infection.

"I think it's important for people to focus on prevention, the actual diseases are quite rare, but there are very simple and easy things that people can do to prevent those illnesses and that's really to prevent mosquito bites in the first place," he said.


Dr. Uren suggests getting standing water out of things like kiddie pools and dog dishes.

"Things that might be left outside that are just breeding grounds for mosquitoes, get rid of those things," he said.

Dr. Uren said you should contact your doctor if you start developing a headache, confusion, stiff neck, joint pains or a fever.

AMCA Fact Sheet by WXYZ-TV Channel 7 Detroit on Scribd

There are mosquito-borne diseases to be aware of here in Michigan, including Eastern Equine Encephalitis (EEE) and West Nile virus (WNV).

Late last month, the Michigan Department of Health and Human Services Bureau of Laboratories collected mosquitoes in Bay, Oakland, and Saginaw counties that tested positive for Jamestown Canyon virus (JCV).

Mosquitoes infected with JCV virus can spread it to people through bites and most cases occur from late spring through mid-fall, according to MDHHS.


State health officials say the symptoms of JCV can include fever, headache, and fatigue. It can cause severe disease in the brain and/or spinal cord including encephalitis and meningitis.

“It only takes one bite from an infected mosquito to cause a severe illness,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy director for health at MDHHS. “We urge Michiganders to take precautions such as using an EPA-registered insect repellent when outdoors, avoiding areas where mosquitoes are present if possible and wearing clothing to cover arms and legs to prevent bites.”

You can also talk to your local health departments to find out about mosquito control programs in your area or how to start one.

Pay attention to the weather forecast if you are going to treat outdoor areas for mosquitoes to avoid the rain washing it away.

Keep children and pets away from treated areas until they're dry or as directed by warnings and instructions on the product.

Walker said you can try bug foggers and other chemical treatments but that it's crucial that you follow the directions on the label or use a professional pest control company.

Walker said repellents with a high percentage of Deet can also be effective.

"I don't particularly care to use them. I don't like the feel of the oiliness or the smell the odor," he said. "But if I have to be outside, that's my best option."

Some people find natural repellents like lemon eucalyptus oil or crushed lavender to also be effective.

Other tips include wearing light-colored clothing and long-sleeve shirts and long pants when outdoors.

Also, make sure the screens on your home are properly maintained to help keep mosquitoes outside.

"Once the adult mosquitoes are out and flying, it's like, you know, the horses are out of the barn. It's something that's a little hard to get control of at that point," Walker said. "It's easier to try to control the mosquitoes in their larval stages, when they're in the water."