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

Officials say a child in Atlantic County and an adult in Middlesex County tested positive for the illness. They say the child showed symptoms in the third week of July, and the adult showed symptoms in the first week of August.

“Both residents have been discharged from the hospital and are recovering at home,” officials wrote in a statement.

Health officials are also investigating four additional suspected cases of human West Nile virus in the state. They also say that there is an additional report of an asymptomatic blood donor in Sussex County.

“For many people, WNV causes asymptomatic infection. One in five persons will develop a mild to moderate illness, typically with a fever, chills, headache, body aches, joint pains, vomiting, diarrhea or rash,” officials wrote.

Health officials say the best way to protect against West Nile virus is to avoid mosquito bites and to limit the conditions around one’s home where mosquitoes can breed – such as removing standing water.