Human case of West Nile virus detected in Michigan after blood donation

The first human case of West Nile virus in Michigan this year has been reported, detected through routine screening of a blood donation. 

The Kent County Health Department in Grand Rapids made that announcement on Thursday, saying it was the first human report of that virus since a West Michigan resident died of the disease during August of 2025. The West Nile virus case also appears to be the first in Michigan this year, according to records kept by the Michigan Department of Health and Human Services and the Centers for Disease Control and Prevention. 

West Nile virus is the most common of the diseases transmitted to humans by infected mosquitoes. The virus has been found in the mosquito populations in several locations this year in Michigan, including in Macomb, St. Clair, Washtenaw and Wayne counties. 

Kent County detected West Nile virus among mosquito samples in the Grand Rapids and Wyoming ZIP codes during late spring.

The Centers for Disease Control and Prevention says there were 222 human cases reported in 32 states as of August 18. 

Another mosquito-borne disease, Eastern equine encephalitis (EEE), was confirmed earlier this week in a resident of Roscommon County in Northern Lower Michigan. 

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.   

Blood testing 

The Centers for Disease Control says all blood donations are tested for multiple diseases before going to the intended patients. 

That testing includes the presence of the West Nile virus. 

Preventing mosquito-borne illness  

"To many people, mosquitoes may just seem like a nuisance, but they can also carry viruses that cause serious illness," said Sara Simmonds, Environmental Health Director for the Kent County Health Department. "Taking simple steps to prevent mosquito bites before they happen is the best way to protect ourselves."   

There are several insect repellents registered with the Environmental Protection Agency that people can apply to themselves before going outside when mosquitoes are active.  

People should wear shoes and socks, long pants, and long-sleeved shirts when they are outside in areas where mosquitoes are known to be present.  

Because mosquitoes lay their eggs on or near water, people should also inspect their homes and outdoor spaces for potential breeding areas. Clean and flush the water in ornamental fountains, pet bowls and bird baths on a regular basis; and repair or discard containers that stay outside and might normally collect water. 

The above video originally aired on June 2, 2026.