BALTIMORE (AP) — Maryland health officials announced Wednesday that they have confirmed the first human case of West Nile Virus in the state this year.

The Department of Health says an adult living in the Baltimore metropolitan area has tested positive for the virus.

The virus is transmitted to humans by mosquitoes infected by feeding on birds with the virus.

Up to 80% of people who are infected will not display any signs of illness at all, but those with underlying health conditions could become seriously ill.

While most people do not develop symptoms from this virus, some people who develop illness may experience mild symptoms such as fever, headache, body aches, a skin rash or swollen lymph glands.