7-18-2025 1:49am

Washtenaw County: Tips for Preventing Insect Bites

Washtenaw County Health Department reminds everyone to prevent mosquito bites whenever possible. Mosquitoes collected in Washtenaw County earlier this summer tested positive for Jamestown Canyon virus. The sample was collected June 12 in the Whitmore Lake area, and results were received this week. No human cases of Jamestown Canyon virus have been reported locally this year, and the last reported case in Washtenaw County was in 2022.

The best way to prevent mosquito-borne infections is to avoid mosquito bites. “Unfortunately, mosquitoes can spread disease,” says Kristen Schweighoefer, MPH, RS, environmental health director with Washtenaw County Health Department. “The Health Department collects and identifies mosquitoes and ticks during the summer months to help understand local and statewide risk of disease transmission.”

Additionally, mosquito pools across Washtenaw County are tested for known mosquito-borne illnesses. The current results confirm the potential for human infection with Jamestown Canyon virus in our local area.

Most people infected with Jamestown Canyon virus do not become ill, or experience only mild illness. In rare cases, infections can become serious. The Health Department does not recommend avoiding the outdoors but urges precautions. Use appropriate repellant, wear protective clothing, and avoid areas with mosquito activity, when possible.

Jamestown Canyon Virus

Jamestown Canyon virus sickened six Michiganders in 2021, one in 2022, four in 2023, and seven in 2024. No 2025 cases have been reported so far. Of the earlier reports, the 2022 case was reported in Washtenaw County. The virus is spread to people through bites from infected mosquitoes. 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. It can cause severe disease in the brain and/or spinal cord including encephalitis and meningitis in rare cases. While Jamestown Canyon virus is found throughout much of the U.S., cases have been increasing in the Midwest. According to the Michigan Department of Health and Human Services (MDHHS), this likely reflects increased awareness and testing but may also be due to an increase in the presence of the virus in the environment.

Other disease risks from mosquitoes and ticks include West Nile virus and Lyme disease. The Health Department reminds everyone to take steps to prevent tick and mosquito bites.

“The best way to avoid tick- and mosquito-borne illnesses is to prevent bites,” according to Susan Ringler Cerniglia, MPH, program administrator with the Washtenaw County Health Department. “Don’t avoid the outdoors but take precautions to avoid bites. Use EPA-approved repellents and check for ticks attached to your body after being outside. If you find a tick on you, remove it immediately.”

Local data on tick and mosquito related illnesses

Lyme disease is the most reported vector-borne disease in the United States. There were 143 cases of Lyme in Washtenaw County residents in 2024. This is a decrease from 2023 (192 cases). The majority (85%) of these cases were likely exposed to the Lyme bacteria in Washtenaw County. As of June 30, 2025, a total of 85 Lyme disease case have been identified locally.

In 2024, West Nile virus was identified in local mosquitoes. No human cases of West Nile virus have been detected in Washtenaw County since 2018.

Additional vector-borne disease data is available on our Communicable Disease Data webpage. More detailed Lyme disease data is on our Lyme and Ticks webpage.

Preventing mosquito bites

Use and EPA-registered insect repellant with an active ingredient such as DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. Follow label instructions. To find one that’s right for you, use the Environmental Protection Agency (EPA)’s insect repellent search tool.
Wear long sleeves, pants, shoes, and socks when outdoors.
Repair screens to keep mosquitoes out of your home.
Reduce mosquito breeding conditions by getting rid of standing water around your home. Once a week, empty flowerpots, barrels, and other items that can hold water.

Preventing tick bites

Check for ticks after being outside. Conduct a full-body tick check using a hand-held mirror, if necessary. Parents should check their children for ticks under the arms, in and around the ears, inside the belly button, behind the knees, between the legs, around the waist, and especially in the hair.

Use insect repellent with 20% or more DEET or other ingredients shown to be effective against ticks, and follow label instructions.
Wear long sleeves, pants, shoes, and socks when outdoors.
Avoid wooded and bushy areas with high grass and leaf litter. Walk in the center of trails.
Bathe or shower as soon as possible after coming inside from outdoor activities and tumble dry clothing on high heat for 10 minutes.
Examine gear and pets for ticks. Ticks can also attach to dogs and cats – do tick checks on pets regularly and talk with your veterinarian about prevention medication.

Tick identification

MDHHS offers tick identification based on photos at no charge for Michigan residents. To submit a photo of a tick for identification, email the photo to MDHHS-Bugs@michigan.gov according to these instructions.

MDHHS does not offer tick testing because the results do not predict infection. Instead, if you are bitten by a tick, monitor for symptoms such as rash, fatigue, fever, headache, muscle pain, or joint swelling/pain occurring within 30 days of the latest tick bite and/or visiting an area with ticks. Some Lyme disease patients do not recall having a tick bite. Seek prompt medical attention if you develop any of these symptoms.