The Florida Department of Health announced Aug. 24 that the fourth human encephalitis case caused by the West Nile virus (WNV) has been confirmed. The case is a 73-year-old woman from Sarasota County, who is believed to have contracted the disease while visiting Marathon in the Florida Keys last month. A medical alert is now in effect for Monroe County.

According to acting state epidemiologist Dr Steven Wiersma, it is not unexpected that this virus has been found in south Florida. “Although it might seem unusual that WNV has now been found in the extreme southern part of Florida, this is consistent with migratory bird patterns. We will intensify our surveillance for human and dead bird cases in south Florida and will continue to provide regular updates.” So far, there have been four confirmed human cases of WNV and two confirmed cases of Eastern equine encephalitis (EEE) in Florida.

The medical alert is currently in effect for 34 Florida counties, including Alachua, Baker, Bay, Bradford, Calhoun, Clay, Columbia, Dixie, Duval, Escambia, Franklin, Gadsden, Gilchrist, Gulf, Hamilton, Holmes, Jackson, Jefferson, Lafayette, Leon, Levy, Liberty, Madison, Monroe, Nassau, Okaloosa, Santa Rosa, St. Johns, Suwannee, Taylor, Union, Wakulla, Walton, and Washington counties.