Jessica Mathews / news@whmi.com


Michigan residents are being urged to take precautions against mosquito bites as the first mosquito-borne virus of 2024 has been detected.

Mosquitos collected in Saginaw County on Wednesday, May 22nd tested positive for Jamestown Canyon Virus (JCV) at the Michigan Department of Health and Human Services Bureau of Laboratories. These are the first infected mosquitos detected for 2024.

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.

MDHHS Chief Medical Executive Dr. Natasha Bagdasarian said “It only takes one bite from an infected mosquito to cause a severe illness. 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.

This year’s warm, wet spring has produced a variety of biting mosquitoes.

The state says the majority are mosquitos that hatched in early May and are currently active in tracts of woodland habitat. Some of the spring mosquitos are capable of transmitting JCV. JCV sickened six Michiganders in 2021, one in 2022, and four in 2023. Also reported last year were 21 cases of WNV.

JCV 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 United States, cases have been increasing in the Midwest. The state said that 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 fourth year that the state lab is offering virus testing of mosquitos collected by local health departments and county mosquito control programs. Testing is offered to improve detection and notification of mosquito-borne viruses.