The Ionia County Health Department has confirmed  a human case of West Nile virus (WNV). This is the first case reported in Ionia County in 2025.

WNV is transmitted to humans through the bites of infected mosquitoes and is the leading cause of mosquito-borne diseases in the United States, but its effects can vary from person to person.  

Most people infected with WNV do not experience symptoms. About 1 in 5 develop mild, flulike illness such as fever, headache, body aches, or rash. About 1 in 150 may develop severe illness affecting the central nervous system, which can sometimes be fatal. Adults who are 50 years and older have the highest risk of illness caused by West Nile virus.