An Oakland County resident and another from Macomb County have tested positive for Jamestown Canyon virus. They have the first confirmed human cases of the mosquito-borne disease in Michigan in 2023, state health officials said.
They may also be the first in the United States to get the virus this year. US Centers for Disease Control and Prevention reported that on July 25had the nation not yet recorded any confirmed human cases by 2023.
From 2011-22, Michigan had 13 confirmed cases of Jamestown Canyon virus, which is most common in the upper midwestern states of Wisconsin and Minnesota, with infections typically occurring in the summer and early fall. The risk is highest in August and September, according to the Michigan Department of Health and Human Services.
“It only takes one bite from an infected mosquito to cause serious illness, so we recommend using insect repellent and wearing long-sleeved shirts and long pants when outdoors during periods when mosquitoes are active,” Dr. Natasha Bagdasarian, Chief Medical Officer of the State. director, said in a statement. “It’s a good idea to take extra precautions during peak mosquito-biting times, which are from dusk to dawn.”
What is Jamestown Canyon virus?
The insects get viruses after feeding on deer, birds and other animals that carry viruses in their blood. Mosquitoes then spread the disease to humans and other animals when they bite them.
More:A small mosquito bite took away Michigan teen Savanah DeHart’s ability to talk, walk
These viruses cannot be spread by coughing, sneezing or touching an infected person.
So far this year, the CDC has reported 69 human cases of West Nile virus nationally, although none have been identified in Michigan. There has been one known human case of Eastern Equine Encephalitis in the United States in 2023, reported in Louisiana.
In 2019, the United States had a record 38 known EEE infections. Ten of the cases were from Michigan, and six of those infected died.
All four of the Michiganders who survived, including Savanah DeHart, of South Portage, were hospitalized, and three of the four had serious neurological problems, state health officials told the Free Press at the time.
What are the symptoms of Jamestown Canyon virus?
Most people who get Jamestown Canyon virus have no symptoms at all. But in those who do, it can cause headaches, fever and fatigue. Others may develop symptoms such as cough, sore throat and runny nose, according to the CDC. Symptoms typically start between two to 14 days after being bitten by an infected mosquito.
In about half of all cases, Jamestown Canyon virus can cause serious illness that affects the brain, such as encephalitis or meningitis, and patients will need hospitalization. Rarely, some people have died from it, the CDC reports.
Symptoms of severe illness from the virus may include:
- High fever
- Stiff neck
- Severe headache
- Muscle weakness
- Loss of coordination
- Difficulty speaking
How is Jamestown Canyon virus treated?
There are no vaccines to prevent the virus in humans, and there are no medications to treat an infection.
Health officials are urging Michiganders to reduce the risk of infection by preventing mosquito bites.
What parts of Michigan have mosquitoes infested?
State health officials are testing mosquito pools throughout the state as part of a Michigan arbovirus surveillance program. They are checking mosquitoes for Jamestown Canyon virus along with West Nile virus and Eastern Equine Encephalitis to assess the risk of human infection.
So far this summer, mosquito pools from Bay, Saginaw and Washtenaw counties have tested positive for Jamestown Canyon virus. West Nile virus has been found in mosquitoes in Kalamazoo, Wayne and Washtenaw counties.
The best way to prevent these diseases is to reduce the number of mosquitoes around your home and avoid mosquito bites, state health officials said. They recommend:
- Remove all sources of standing water around your home where mosquitoes can breed, including water in birdbaths, old tires and any other object that holds water, including abandoned swimming pools and wading pools.
- Make sure doors and windows have tight-fitting screens without tears, holes or other openings.
- When outdoors, use an EPA-registered insect repellent with active ingredients such as DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthan-diol, and 2-undecanone.
- Wearing shoes and socks, light-colored long pants, and long-sleeved shirts when outdoors.
- Take extra precautions outdoors when mosquitoes are most active, between dusk and dawn.
- Do not use insect repellent on infants under 2 months of age. Instead, dress babies in clothes that cover arms and legs, and cover cots, strollers and carriers with mosquito nets.
- Using the bed net when sleeping outdoors or in conditions without window screens.
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