INDIAN RIVER COUNTY, Fla. — University of Florida scientists have identified the northern Treasure Coast as one of five areas in the state they will be closely watching in the coming weeks for evidence that West Nile virus and other mosquito-borne diseases might spread among humans.
"What happens in the next six to eight weeks is critical," said Jon Day, medical entomologist with UF's Institute of Food and Agricultural Sciences lab in Vero Beach. During that time, Day and his colleagues will be looking for heavy rainfall, large numbers of a certain freshwater mosquito species and lots of fledgling birds. A convergence of all these factors could presage an epidemic of West Nile or St. Louis encephalitis among humans.
"What we want to do is communicate with public health and mosquito control workers in those areas," Day said. "This tells us exactly where to look for possible (viral) transmission."
Brevard, Indian River and Osceola counties are among areas Day and fellow researchers believe are primed for mosquito-borne disease, based on current groundwater levels.
Other areas of interest are eastern Palm Beach County; Broward and Miami-Dade counties; Lee, Monroe and Collier counties; and Pinellas County.
Martin and St. Lucie counties were not in any areas of interest shown on the map, published for the last week of April. Another update is expected in about three weeks, Day said.
Once infected with West Nile or St. Louis encephalitis viruses, most people experience a mild fever and headache. Some people, however, experience more severe symptoms, including a sustained high fever, a persistent headache, a rash and neurological symptoms including blurred vision, slurred speech and muscle tremors. Survivors often experience neurological damage that lasts for years. The viruses have a fatality rate of about 5 percent.
Since its arrival in Florida in 2001, West Nile has been responsible for intermittent outbreaks throughout the state. The largest occurred in 2003, when there were 92 human cases and six deaths. Most of the cases occurred in the western Florida panhandle and only one case was reported along the Treasure Coast, Day said.
The last large-scale epidemic of St. Louis encephalitis occurred in 1990, when the disease was confirmed in 223 Floridians. Eleven died, including one Vero Beach woman.