Deadly virus found in Kent County mosquito during routine testing

GRAND RAPIDS, Mich. (WOOD) — The Kent County Health Department says a mosquito found in a testing pool has tested positive for Jamestown Canyon virus .

JCV is one of several diseases that can be spread from mosquitoes to humans that health department officials routinely watch for each summer. This case was found in a pool in the 49504 zip code, which covers part of northwest Grand Rapids and the southeast edge of Walker.

JCV was last detected in Kent County in 2021 in the same trap location, Brendan Earl, the supervising sanitarian for the Kent County Health Department, said. There were six human cases across Michigan that year. Earl said he’s not surprised the virus is back, saying the mild winter has allowed more mosquitoes to emerge this year. West Nile virus showed up in testing six weeks earlier than normal, Earl said.

So far this summer, there have been no confirmed human infections of any mosquito-borne viruses in Michigan.

Typically, a person infected with JCV will experience a fever, headache and fatigue. In rare instances, the disease can cause serious health problems, including encephalitis and meningitis, which can be deadly.

There are no vaccines or medications to treat or prevent JCV, which is why health experts recommend people take the proper precautions to avoid mosquito bites.

“Our point is not to scare people from going outside,” Earl told News 8. “It’s just to have a general awareness that these viruses are out in the environment.”

The KCHD recommends several preventative measures, including:

• Wearing mosquito repellent that contains between 10% to 35% DEET
• Wearing light-colored and long-sleeved shirts and pants
• Staying indoors during dusk
• Removing or refreshing water in bird baths, wading pools and any other standing water
• Ensuring window screens are properly sealed.

Mosquitos lay their eggs in standing water, making it a breeding ground. Flooding and heavy rain in West Michigan early Monday and more projected into Tuesday morning will only create more opportunities for mosquitos to grow.

“Their larval lifestyle requires them to be in water,” Earl said. “If you dump them out, we always call it tip and toss, you’ll get rid of entire generations of mosquitos.”

The latest data from the Michigan Department of Health and Human Services , released on Friday, shows five cases of mosquito-borne infections in animals and 17 positive tests in mosquitoes from testing pools.

All five animal cases have been found in birds. All five are infected with West Nile virus, and have been found in Delta, Luce, Marquette, Mason and Saginaw counties.

Seven mosquitoes have tested positive for West Nile virus, including three in Kent and Bay counties and one in St. Clair County. Ten mosquitoes have tested positive for JCV, including four in Saginaw County, three in bay County, and one each in Calhoun , Dickinson and Kent counties.

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