Oakland County Public Health officials announced that a sample from a "mosquito pool" in Royal Oak has tested positive for the West Nile Virus.
The mosquitos were collected on Aug. 12, 2025, at Tenhave Woods/Quickstad Park as part of a "mosquito pool"—a test site meant to trap the Culex species of the insect known for carrying West Nile. The County maintains 10 such trap sites throughout the region, collecting and analyzing samples weekly throughout each summer and early fall.
This is the first positive result in the County in 2025. County officials confirm that the timing is common: West Nile is endemic—always present in nature to some degree. It takes time each year for the virus to spread amongst mosquitoes in our area, so it’s common to see the first positive tests around mid-August.
What is West Nile Virus?
West Nile virus is a single-stranded RNA virus primarily transmitted by the Culex species of mosquitoes. It can cause West Nile fever, which may lead to more severe neurological diseases such as meningitis or encephalitis. Common symptoms include fever, rash, muscle aches, and in rare cases, serious brain inflammation.
How did West Nile get into our community?
West Nile is endemic—always present in nature. It takes time each year for the virus to spread amongst mosquitoes in our area, so it’s common to see the first positive tests around mid-August.
What is the City doing to combat mosquitos and mosquito-borne illnesses?
The City Commission approves our participation each year in the Oakland County West Nile Grant Program. The Department of Public Services purchases and treats catch basins and other areas of standing water with mosquito larvicide tablets, with a partial financial reimbursement from Oakland County.
What should I do to stay safe in parks and greenspaces?
According to County health experts, the best thing you can do is use an Environmental Protection Agency (EPA) registered insect repellent. All EPA-registered insect repellents are evaluated for safety and effectiveness, and will contain DEET, picaridin, IR3535, Oil of Lemon Eucalyptus or para-menthane-diol as the active ingredient. Repellents containing a higher percentage of the active ingredient typically provide longer-lasting protection. Always follow the product label instructions.
Additional tips:
- Wear long-sleeved shirts and pants.
- Limit outdoor activity from dusk to dawn when mosquitoes are most active.
- Be especially careful between August and autumn.
- Older adults and immune-compromised people are more at risk.
What can I do to keep my home and yard safe?
- Get rid of mosquito breeding sites by removing standing water around your home.
- Turn over any container that can collect water. Once a week, empty items that hold water such as tires, buckets, planters, toys, pools, birdbaths, pet bowls, flowerpots and trash containers.
- Clean clogged roof gutters, especially if leaves tend to plug the drains.
- Treat standing water - such as retention ponds or drainage ditches - with a mosquito larvicide. It is easy to use and can be purchased at most home improvement stores.
- Cover holes in window and door screens. Do not prop open doors.
- Be especially careful between August and autumn.
Additional information
See Oakland County's West Nile information page for more information.