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Residents urged to protect against mosquito bites as first mosquito-borne virus of 2023 detected in Saginaw County

LANSING, Mich. – Michiganders are being urged to take precautions against mosquito bites as mosquitos recently collected in Saginaw County have tested positive for Jamestown Canyon virus (JCV) at the Michigan Department of Health and Human Services Bureau of Laboratories (MDHHS BOL). These are the first infected mosquitos detected for any virus for 2023.

Residents are reminded that the best way to protect themselves against JCV and other mosquito-borne illnesses, including eastern equine encephalitis (EEE) and West Nile virus (WNV), is to prevent mosquito bites.

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

Every summer in Michigan, bites from mosquitos carry the risk of spreading diseases to people and animals. While the current dry weather conditions have limited the number of biting mosquitos, spring mosquitos that emerged in early May are still active in portions of the state, especially in areas with large tracts of woodland habitat. Some of these spring mosquitos are capable of transmitting JCV. JCV sickened six Michiganders in 2021 and one in 2022. Also reported last year were 12 cases of WNV.

The JCV virus is spread to people through bites from infected mosquitos. Most cases occur from late spring through mid-fall. Illness can develop within a few days to two weeks following a bite from an infected mosquito. While most people do not become ill, initial symptoms can include fever, headache and fatigue. In rare cases, it can cause severe disease in the brain and/or spinal cord including encephalitis and meningitis.

While the JCV is found throughout much of the U.S., cases have been increasing in the Midwest. This likely reflects increased awareness and testing but may also be due to an increase in the presence of the virus in the environment. This is the third year that the MDHHS BOL is offering virus testing of mosquito pools collected by local health departments and county mosquito control programs. Testing is offered to improve detection and notification of mosquito-borne viruses.

JCV can be spread by mosquitos that become infected when they feed on deer or other animals that have the virus in their blood. Infected mosquitos spread the virus to other animals or people through bites. Arboviruses, including WNV and EEE, spread when mosquitos contract the virus from biting infected birds then biting a human.

Residents can stay healthy by using simple, effective strategies to protect themselves and their families. The following steps are recommended to avoid mosquito-borne diseases:

  • Apply insect repellents that contain the active ingredient DEET or other EPA-approved products to exposed skin or clothing. Always follow the manufacturer’s directions for use.
  • 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 mosquitos outside.
  • Empty water from mosquito breeding sites around the home, such as buckets, unused kiddie pools, old tires and other water-holding containers where mosquitos can lay eggs.

“Mosquitoes may seem like a small nuisance, but they can spread deadly diseases like West Nile virus and eastern equine encephalitis through their bites,” said Mike Philip, Michigan Department of Agriculture Rural Development (MDARD) Pesticide and Plant Pest Management division director. “Michiganders can help limit the risk of disease outbreaks by developing a mosquito prevention strategy to reduce pest populations.”

To combat the spread of this disease in animals, owners can:

  • Talk to a veterinarian about vaccinating horses against WNV and other mosquito-borne diseases.
  • Place livestock in a barn under fans (as mosquitos are not strong flyers) and pets inside the home during peak mosquito activity from dusk to dawn.
  • Use an insect repellant on animals that is approved for the species.
  • Eliminate standing water on the property—i.e., fill in puddles, repair eaves, and change the water in buckets and bowls at least once a day.
  • Contact a veterinarian if an animal shows signs of illness.

Michiganders can also hire a mosquito control business. Mosquito control businesses are required to be licensed to apply pesticides in Michigan and must meet certain experience requirements, employ certified pesticide applicators who have passed MDARD proficiency examinations and meet financial requirements including proof of insurance. Use MDARD’s list of licensed pesticide applicator businesses in Michigan to find qualified mosquito abatement applicators.

For more information about mosquito-borne diseases, visit

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