NEW JERSEY — New Jersey officials reported the state's first human West Nile virus cases this year, which hospitalized three people. Two of them are recovering at home, while one remains in the hospital, according to Thursday's joint announcement from state health, environmental and agricultural officials.

Three men tested positive for the mosquito-borne virus earlier this month in Bergen, Morris and Ocean Counties. Two are in their 50s, and one is in his 80s, according to state officials.

For many people, West Nile virus causes asymptomatic infection or a mild-to-moderate illness. But people older than 50 and individuals with weak immune systems carry a greater risk of developing severe illness. About one in 150 people will develop a more severe form of the disease, with symptoms that include a severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

New Jersey reports eight human infections from the virus in a typical year. But last year, the New Jersey Department of Health tallied 36 infections, including five deaths.

Early West Nile virus symptoms may be confused with COVID-19 or other common viral illnesses. Specific laboratory tests are necessary to confirm West Nile virus, but there is no specific treatment for it, state officials said.

West Nile virus activity is elevated in mosquitoes this year but is similar to five-year average trends, said a joint statement from New Jersey's health, environmental and agricultural officials. The best way to prevent the disease is to avoid mosquito bites.

Health officials perform arboviral testing on mosquito pools each week and have found the virus in 293 mosquito pools in the state this year — nearly 40 percent lower than the tally of 477 infected pools at this time last year. Check out New Jersey's map of arboviral activity to see where arboviral diseases have been detected.

"August and September are the months that we see most West Nile virus cases in New Jersey," said state Health Commissioner Judith Persichilli. "It is important that residents take steps to protect themselves by using an EPA-registered insect repellent, wearing long sleeves and pants and avoiding the outdoors during dawn and dusk when mosquitoes are most active."

West Nile virus can also affect a horse's neurological system. New Jersey hasn't reported any cases in horses this year, but state officials encouraged equine owners to get their animals vaccinated against illnesses such as West Nile virus and Eastern Equine Encephalitis — another illness spread through an infected mosquito's bite.

State officials asked residents, business owners and contractors to take steps to reduce mosquito populations on their properties by emptying or changing outdoor standing water at least weekly to stop mosquito breeding. Areas that may require attention include flowerpots, pet food and water dishes, birdbaths, swimming pool covers, clogged rain gutters, plastic wading pools and wheelbarrows, and any containers or trash that may be difficult to see, such as under bushes, homes or around building exteriors.

People can also reduce mosquito contact by using air-conditioning when possible and ensuring window screens are in good repair. Here are some mosquito-proofing tips.

"Controlling New Jersey’s mosquito population is a major part of protecting our public health," said state Environmental Protection Commissioner Shawn M. LaTourette. "While we have been seeing unusually dry weather this summer, people can help by removing any standing water in their yards and covering any empty containers that can hold water for more than three days. Even small amounts of rain following these drought-like conditions can produce significant numbers of container-inhabiting mosquitoes known to spread West Nile virus."

Officials encouraged the public to report mosquito concerns to their county mosquito-control agency. Find more info on West Nile virus from the New Jersey Department of Health.

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