by First Human Case of West Nile Virus in Michigan for 2025 Confirmed in Livingston County
Michigan health officials have confirmed the state’s first human case of West Nile virus for 2025 in a resident of Livingston County. The announcement from the Michigan Department of Health and Human Services (MDHHS) comes with a strong reminder that the peak season for mosquito-borne illnesses is underway, urging residents across the state to take precautions.
While the MDHHS has not released any personal details about the individual, the case serves as a critical alert. “It only takes one bite from an infected mosquito to cause a severe illness,” warned Dr. Natasha Bagdasarian, the state’s chief medical executive. “Use insect repellent and wear long-sleeved shirts and long pants when outdoors during times when mosquitoes are active. These precautions are especially important during peak mosquito-biting hours, which are from dusk to dawn.”
The risk is not isolated to one area. Health officials have detected West Nile virus in mosquito populations in numerous counties this year, including Bay, Kalamazoo, Kent, Macomb, Midland, Saginaw, Tuscola, and Wayne counties. Another mosquito-borne illness, the Jamestown Canyon virus, has also been identified in mosquito pools in Bay, Kalamazoo, Macomb, Ottawa, Saginaw, and Washtenaw counties. With August and September being the most active months for transmission, the threat remains widespread.
Understanding the Symptoms of West Nile Virus
West Nile is the leading cause of mosquito-borne illness in the United States, yet its effects can vary dramatically from person to person. There are no specific vaccines or treatments available for humans, making prevention the only defense.
The Silent Majority: No Symptoms at All
For most people, a West Nile virus infection goes completely unnoticed. The Centers for Disease Control and Prevention (CDC) estimates that about 8 out of 10 infected individuals show no symptoms at all and may never know they had the virus.
The Common Febrile Illness
About one in five people who are infected will develop what is known as West Nile fever. Symptoms are often flu-like and can include fever, headache, body aches, joint pain, vomiting, diarrhea, and sometimes a rash. While most people with this form of the illness recover fully, the fatigue and weakness can linger for weeks or even months, significantly impacting their quality of life.
The Severe Neurological Impact
For a small fraction of individuals—about 1 in 150—the infection becomes much more serious, attacking the central nervous system. This can lead to severe neurological diseases such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes surrounding the brain and spinal cord).
The symptoms of a severe infection are alarming and require immediate medical attention. They include:
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High fever
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Severe headache
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Neck stiffness
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Stupor or disorientation
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Coma
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Tremors or convulsions
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Muscle weakness and paralysis
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Vision loss
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Numbness
While severe illness can affect people of any age, those over 60 are at a significantly higher risk. People with certain underlying medical conditions—such as cancer, diabetes, hypertension, or kidney disease—and organ transplant recipients are also more vulnerable. Recovery from a severe neurological infection can be a long road, taking several weeks or months, and some individuals may be left with permanent neurological damage. Tragically, about 1 in 10 people who develop a severe central nervous system infection from West Nile virus do not survive.
How to Protect Yourself and Your Family
The virus is transmitted through the bite of an infected mosquito that has fed on an infected bird. The best way to avoid West Nile virus is to prevent mosquito bites. The MDHHS recommends the following practical steps:
1. Your First Line of Defense: Repellent
The most effective way to prevent mosquito bites is to use an EPA-registered insect repellent. Look for products containing active ingredients like DEET, picaridin, IR3535, or oil of lemon eucalyptus. Always follow the instructions on the product label and reapply as directed, especially after swimming or sweating. For children under two months old, avoid using repellent. Instead, dress them in clothing that covers their arms and legs and use mosquito netting over cribs, strollers, and baby carriers.
2. Dress for Protection
When you plan to be outdoors, especially during dusk and dawn, wear shoes, socks, and light-colored, loose-fitting long pants and long-sleeved shirts. The extra layer of clothing provides a physical barrier against mosquitoes.
3. Secure Your Home Environment
Make your home a mosquito-free zone. Ensure all doors and windows have tight-fitting screens without any tears or openings. If you sleep outdoors or in rooms without screens, use bed nets for protection.
4. Eliminate Mosquito Breeding Grounds
Mosquitoes lay their eggs in standing water. Once a week, walk around your property and eliminate any sources of stagnant water. This includes emptying bird baths, wading pools, and old tires. Check gutters for clogs and turn over any objects like buckets, planters, or toys that can collect water.
