After two more cases of flesh-eating bacteria infections were reported from Florida waters recently, Tampa Bay area physicians are warning residents and visitors to be careful swimming in brackish water or eating uncooked seafood.

A 77-year-old woman from Ellenton was infected by flesh-eating bacteria and died nearly two weeks after she fell and scraped her leg while walking on Anna Maria Island. The case came just weeks after the mother of a 12-year-old Indiana girl wrote on Facebook that she believes her daughter contracted the same infection during a trip to Destin in early June.

"Necrotizing fasciitis" is an infection caused by bacteria that stops blood circulation and causes tissue to die and skin to decay. The infection is somewhat rare, and can come from different strains of bacteria, doctors say. But it's called "flesh-eating" because the infection is so rapidly progressing.

Here's what you need to know about it:

What are my chances of catching it if I go in the water?

Most healthy adults will be able to fight off a necrotizing fasciitis infection without hospital care.

It's the elderly, children and people with compromised immune systems or issues like liver disease who are more susceptible to the infection — if they have open wounds or lesions. People in these categories should avoid going in warm saltwater or brackish water, hot tubs and swimming pools. They also should avoid eating raw seafood, like crab, oysters or sushi.

But the easiest way to avoid contracting the infection is to wash your hands regularly.

How seriously should I take this?

Even with treatment, one in three patients die from necrotizing fasciitis, according to the U.S. Centers for Disease Control and Prevention. Since 2010, the agency estimates between 700 and 1,200 people a year have contracted the infection in the United States. But cases have gone up in the last year in Florida, local physicians said.

The infection destroys the skin and tissue that covers the muscle within 12 to 24 hours, and the bacteria releases toxins into the tissue over time, causing it to die and decay. It can be quite painful, so doctors recommend seeking treatment as soon as possible if you don't feel well.

Usually, swelling occurs right away and blisters can form over the wound site. Those blisters will turn black and blue over time as tissue and skin begins to die.

Those who have the infection will feel flu-like symptoms of fever, dizziness and cold sweats right away. Severe complications are common, like sepsis, shock and organ failure.

Recovering from necrotizing fasciitis depends on how fast the infection is caught and treated by medical professionals. Multiple surgeries are fairly common to remove infected tissue, as are long courses of potent antibiotics.

How do you catch it?

In April, there were two cases of necrotizing fasciitis in Tampa Bay reported in men who spent time on the water. Mike Walton was fishing in the Gulf of Mexico over Easter weekend when he contracted it through a cut on his hand from a fish hook. He was treated at Tampa General Hospital. Barry Briggs developed an infection during a boating trip to Weedon Island. It wasn't until he returned home to Ohio that he began experiencing symptoms, and nearly lost his foot to the aggressive bacteria.

But both of those cases came from the group "A Streptococcus" bacteria, the same bacteria that causes strep throat, and which is generally considered the most common cause of necrotizing fasciitis, according to the CDC. That means you don't necessarily have to go into the water with an open cut to catch it. You can just be unlucky.

In Florida, physicians generally see strep A bacteria infections peak from winter through spring. The type of bacteria most commonly contracted through warm water, like in the Gulf of Mexico, is usually seen this time of the year and throughout hurricane season.

Contact Justine Griffin at jgriffin@tampabay.com or (727) 893-8467. Follow @SunBizGriffin.