All residents of areas where West Nile virus activity has been identified are at risk of getting West Nile neuro-invasive disease or West Nile fever. In Michigan, the virus has become endemic throughout the state. People over 50 years of age are at the highest risk of developing severe illness. In addition, immunocompromised persons or people with underlying health conditions have an increased risk of developing more severe forms of WNV illness. People over 75 are more likley to die from a WNV infection.