Volusia County lifeguards are flying the purple flag to warn swimmers of jellyfish after about 800 people were treated for stings Saturday through Monday, a Beach Safety Ocean Rescue official said.
Moon jellyfish are believed to be responsible for the surfeit of stings, Capt. Tammy Malphurs said.
If stung, flag down a Beach Safety vehicle or go to a staffed lifeguard tower, Malphurs said.
Oceana, the nonprofit organization, says "the moon jelly’s tentacles are covered with specialized stinging cells, called cnidocytes. The moon jelly uses these stinging cells to hunt small pelagic invertebrates and occasionally fishes and to capture other food particles with which it might come in contact. The cnidocytes are also the source of the sting that people feel when we come in contact with a moon jelly."
Scientists believe moon jellies and other jellies thrive in areas affected by human activity, according to Oceana.
Most jellyfish stings can be treated with rinsing the area with vinegar, according to the Mayo Clinic. Methods found to be unhelpful or unproven include: scraping out stingers, rinsing with seawater, rinsing with human urine, rinsing with fresh water, applying meat tenderizer, applying alcohol, ethanol or ammonia, rubbing with a towel and applying pressure bandages.