A great blue heron found in Cass County has tested positive for West Nile virus, the Van Buren/Cass District Health Department announced Thursday. The finding adds to the 69 birds statewide that have tested positive for the virus so far in 2025.

West Nile virus is a mosquito-borne illness that can affect humans and animals. Most people infected do not experience symptoms, but about one in five may develop West Nile fever, which can include fever, headache, body aches, fatigue, and sometimes a rash. In rare cases, the virus can cause severe neurological illness.

Officials are reminding residents to take precautions to reduce mosquito breeding and protect themselves:

• Remove standing water from containers such as flowerpots, buckets, tires, and gutters.
• Use EPA-registered insect repellents containing DEET, picaridin, or oil of lemon eucalyptus.
• Wear long sleeves and pants outdoors, particularly during dawn and dusk when mosquitoes are most active.

While the detection of West Nile virus in birds does not mean human cases will occur, it serves as an early warning of the virus’s presence in the local mosquito population. The health department will continue to monitor mosquito activity and provide updates to the public.

For more information on local programs, services, and public health updates, visit VBCDHD.org.

Image courtesy Michigan Department of Natural Resources.