A Town of Brookhaven resident has tested positive for West Nile virus, bringing to three the number of human cases reported this year in Suffolk County, health officials said Wednesday.

The most recent resident, who is over 50 years old, started experiencing symptoms in mid-August, was hospitalized and is now recuperating at home, officials said. The earlier cases were both from the Town of Smithtown, one under 50 and the other over 55.

“We know only about the cases in which the patient sought treatment and we received laboratory confirmation of West Nile virus,” Dr. James Tomarken, Suffolk’s commissioner of health services, said in a news release. “There may be many more residents who acquired West Nile virus, but we never learned about them because they didn’t seek medical attention or they sought attention but lab tests weren’t ordered.”

Nassau is reporting six human cases — two individuals under 50 and four over 50 — with none currently hospitalized, said a spokeswoman for the Nassau County health department.

advertisement | advertise on newsday

Humans contract the virus through bites of infected mosquitoes, with about 20 percent of people infected developing noticeable symptoms. Mild symptoms can include fever, head and body aches, skin rash and swollen lymph glands, with high fever, headache, neck stiffness, disorientation, muscle weakness, numbness and paralysis among the more severe symptoms, Suffolk health officials said.

Among those most at risk for the virus, which can be fatal, are people over 50 years old and those with chronic illness or compromised immune systems.

Suffolk reported five human cases each in 2016 and 2015, with no deaths. Nassau saw seven human cases — including one death in 2016 and nine human cases and no deaths in 2015. For the 2016 season nationally, 2,038 cases of West Nile virus had been reported to the federal Centers for Disease Control and Prevention, as of Jan. 17.