The New Jersey Department of Health has confirmed the state’s first human cases of West Nile virus this year.

Two residents — one older than 70, the other under 18 years of age — tested positive for the disease, with symptoms reported the first week of July. From Union and Middlesex counties, the two people infected were hospitalized and have since been discharged. An additional report of an asymptomatic West Nile virus-positive blood donor was reported in Somerset County.

Cases of West Nile virus typically occur in New Jersey from mid- August to mid-September. Last year, there were 14 confirmed cases in the state.

“This year, New Jersey is seeing higher than average West Nile virus activity earlier than expected. As mosquito season can last into October, bite prevention will be essential in protecting yourself and your family against mosquito-borne diseases like West Nile virus in the remaining summer months and into the fall,” said New Jersey Health Commissioner Dr. Kaitlan Baston. “This means avoiding mosquito bites through tried-and-true methods, like using insect repellants, wearing long sleeves and pants, and limiting outdoor activity during peak times for mosquito activity.”

West Nile virus causes asymptomatic infection or a mild to moderate illness, typically with a fever, in most cases. People over age 50 and those with weakened immune systems are at greater risk of developing severe illness. About one in 150 people will develop a more severe form of the disease, with symptoms such as a severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.