This came up on another forum, this is what I found out about it. This goes beyond Florida, see below. If you are in warm seawater, seems like something to be both aware of and concerned about. Particularly if you go in with cuts, open wounds duct taped over, etc.. It seems to infect through cuts, open wounds and through consumption of raw/under cooked seafood like oysters. "State health officials say at least nine people have died so far this year in Florida " "CDC received reports of more
than 900 V. vulnificus infections from the Gulf Coast states, where most cases occur."
"What type of illness does V. vulnificus cause?
V. vulnificus can cause disease in those who eat contaminated seafood or have an open wound that is exposed to seawater. Among healthy people, ingestion of V. vulnificus can cause vomiting, diarrhea, and abdominal pain. In immunocompromised persons, particularly those with chronic liver disease, V. vulnificus can infect the bloodstream, causing a severe and life-threatening illness characterized by fever and chills, decreased blood pressure (septic shock), and blistering skin lesions. V. vulnificus bloodstream infections are fatal about 50% of the time.
V. vulnificus can cause an infection of the skin when open wounds are exposed to warm seawater; these infections may lead to skin breakdown and ulceration. Persons who are immunocompromised are at higher risk for invasion of the organism into the bloodstream and potentially fatal complications."
CDC - Vibrio vulnificus: General Information - NCZVED
They say activity may be depressed below 20 C or about 68 F. That is chilly in my book. At what temperature it really becomes a problem is a more complicated question unfortunately. Salinity is also tied into the events. The bacteria prefers low salinity water. It looks like the majority of infections have followed ingestion of seafood and about 25% through exposure of open wounds to seawater.
"Incidence
An average of 50 culture-confirmed cases, 45 hospitalizations, and 16 deaths are reported each year from the Gulf Coast region (reporting states are Alabama, Florida, Louisiana, Mississippi, and Texas). Nationwide, there are as many as 95 cases (half of which are culture confirmed), 85 hospitalizations, and 35 deaths."
CDC - Vibrio vulnificus, Technical Information - NCZVED
Precautions:
"Persons with open wounds:
Avoid contact between open wounds and seawater, especially if water temperature is more than 68°F (20°C), or raw seafood
Wash any wound that is exposed to seawater with soap and clean water
Immediately seek medical care for any wound that appears infected"
Vibrio vulnificus Infection: Diagnosis and Treatment - American Family Physician