I got this from another site.
Vibrio vulnificus is a bacterium that is a rare cause of illness in the United States. Infection with V. vulnificus is a serious health threat that predominantly affects people with a compromised immune system or an underlying illness, especially liver disease.
The bacteria is a natural inhabitant of coastal waters. People who develop wound infections generally do so following contamination of a pre-existing wound or through an injury acquired while exposed to brackish or salt water. V. vulnificus infection is very rare among children.
Vibrio naturally occur in estuaries like the Indian River Lagoon and are not a result of human pollution. Their presence is directly linked to temperature and salinity, being most abundant in warm (17-35 °C), brackish (5-25 ppt.) waters. Because of Florida’s warm climate, Vibrio are present in areas of the IRL year-round. V. vulnificus is most likely to be encountered in stagnant, inshore waters (especially near freshwater discharge) rather than in the ocean due to their inability to tolerate high salinities. However, events like rainfall, freshwater release, and low tides can temporarily move water containing these bacteria into areas where they are not normally present.
Local oysters, crabs, shrimp and fish carry Vibrio if they live in areas where it is present. Anglers should be aware of these hazards and use caution when handling fish and bait. Proper footwear should be used when wading to prevent injury. Open wounds should never be exposed to the environment and all seafood should be cooked thoroughly. Fear of V. vulnificus should not keep you out of our local waters this summer- it’s always been here, only a small percent of the population is considered “at risk” and infections are easy to prevent if you follow the safety recommendations below.