A human case of West Nile virus has been reported in an Oakland County resident – the second such case confirmed this year in Michigan. 

No travel was reported by the patient, the Oakland County Health Division said in its statement issued Monday. 

"This is an important reminder that West Nile Virus is present in our community," said Kate Guzman, health officer for Oakland County Health Division. "We strongly encourage residents to protect themselves from mosquitoes until the first hard frost of the year." 

No details about the patient — other than a lack of travel — have been released by the health department. 

This is the first human case of West Nile virus in Oakland County confirmed in 2025; the second in the state this year. The earlier case was reported out of Livingston County. 

What is West Nile virus? 

Mosquitoes are infected with the West Nile virus by biting an infected bird. The virus can then spread to humans through the bite of an infected mosquito. 

Most people who are infected with the virus have either no symptoms or experience a mild illness such as fever, headache, and body aches. But in some people, more serious conditions such as inflammation and swelling of the brain can occur.  

People older than 50 are more likely to develop serious and potentially life-threatening symptoms of West Nile Virus if they do get sick. 

Where has it been found this summer? 

While this is only the second human case in Michigan this year, there are several counties where local health authorities have confirmed West Nile virus among the local mosquito populations. 

West Nile has also been confirmed among mosquitoes this summer in Windsor, Ontario. 

How to limit the spread in humans 

Health officials recommend people take precautions against mosquito bites so to limit the spread of mosquito-borne diseases.  

Those steps include using an insect repellent registered with the Environmental Protection Agency, and removing standing water around homes and outdoor property where mosquitoes could breed.