With 31 new mosquito samples testing positive for West Nile virus, the total for the year is now 158 in Suffolk County, health officials reported Friday.

The new samples, all Culex pipiens-restuans, were collected Sept. 1 to Sept. 3 in Lindenhurst, North Babylon, West Babylon, Copiague, Huntington, South Huntington, Huntington Station, Northport, Dix Hills, Smithtown, Nesconset, Holbrook, Holtsville, Farmingville, Stony Brook, Setauket, Port Jefferson Station, Rocky Point, East Hampton, and Southold.

Nassau County is reporting 47 positive mosquito samples, a health department spokeswoman said.

Also, on Thursday two human West Nile virus cases were reported for this year, one in each county.

A man older than 55 in the Town of Islip has been hospitalized since late August with West Nile symptoms, said Suffolk health officials, who had no further word on his condition.

And a woman younger than 50 in the Town of Oyster Bay was hospitalized in mid-August and is now recovering at home, said a Nassau health department spokeswoman.

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Some mosquito bites can transmit West Nile to humans, with mosquitoes picking up the virus by feeding on infected birds.

"The confirmation of West Nile virus in mosquito samples or birds indicates the presence of West Nile virus in the area," said Dr. James L. Tomarken, county health services commissioner.

"While there is no cause for alarm, we urge residents to cooperate with us in our efforts to reduce the exposure to the virus, which can be debilitating to humans."

In some cases, the virus causes serious neurological illnesses that can lead to health conditions or death.

Nassau had four reported human cases of West Nile and no deaths, last year, with Suffolk reporting one case and no deaths.

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Last year, 2,205 cases of human infection were reported in the United States, resulting in 97 deaths, according to the federal Centers for Disease Control and Prevention.

Residents are advised to eliminate stagnant water where mosquitoes breed in and around their homes; to minimize outdoor activities and cover their skin in the evening and night when mosquitoes are most active; and to use mosquito repellent outdoors.

Learn more at www.suffolkcountyny.gov/Departments/HealthServices/PublicHealth/PreventiveServices/ArthropodborneDiseaseProgram/PreventingMosquitoBorneIllnesses.aspx