As Nassau County reported 18 additional sites Thursday where mosquitoes have tested positive for West Nile virus, the state issued a public health threat declaration for the county and urged downstate residents to protect themselves from mosquito bites.

Late last month, Nassau identified what it said was the first human case statewide, a New Hyde Park woman, 66, whose symptoms appeared July 5. State confirmation on the Nassau case and a suspected Suffolk case involving a man, 72, from the Town of Huntington is pending.

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Nassau Health Commissioner Dr. Maria Torroella Carney said she requested this year's threat declaration to convey the real risk posed by the mosquito-borne disease.

>> Read Jennifer Smith's full story