By Amanda Gardner

HealthDay Reporter

THURSDAY, May 24 (HealthDay News) -- Despite scary headlines by the score, most people don't have to fear that they'll be the next victim of the so-called flesh-eating bacteria disease, experts say.

"Only about 10,000 to 12,000 cases are reported a year in the U.S.," said Dr. Pascal James Imperato, dean of the School of Public Health at State University of New York Downstate Medical Center. "It's relatively rare."

Flesh-eating bacteria, known scientifically as necrotizing fasciitis, occurs when certain types of bacteria penetrate the skin and then invade the blood system, eventually eating away at muscle and fat tissue.

People who have weakened immune systems, such as the elderly, people with diabetes and people taking immune-suppressing drugs are more at risk for the condition. Sports teams or people who congregate in close vicinity could also be at higher risk, said Dr. Kenneth Bromberg, director of the Vaccine Research Center at The Brooklyn Hospital Center in New York City.

"But," added Imperato, "there are also instances where there is no apparent disposing factor, and it can occur in people [who are] relatively young and healthy, so it has a certain unpredictability to it."

So it has been with three relatively young people in the southeastern United States who became infected recently.

The first was a 24-year-old graduate student in Georgia who has been on a ventilator and, so far, has had both hands, a leg and the other foot amputated. The infection took hold after she cut her leg falling from a homemade zip line.

Another victim, who is 33 and also lives in Georgia, has already undergone five operations, had two pounds of dying tissue from his groin area removed and will still have to endure skin grafts and reconstructive surgery, according to USA Today.

The third patient is a 36-year-old mother of newborn twins in South Carolina who has had seven surgeries and remains in critical condition, according to CNN.

Necrotizing fasciitis can be caused by any one of a number of bacterium, said Bromberg.

The major culprits can be quite common in the environment and include Streptococcus, which can also cause strep throat, and Staphylococcus aureus, although sometimes more than one bacteria can be contributing to the problem, Imperato said.

But even infection with the chicken pox virus can result -- albeit rarely -- in necrotizing fasciitis.

Most of the time, an infection "will begin and abort very quickly as the body's immune system is sufficient to terminate it before it progresses to a stage where a limb or an arm becomes severely swollen and undergoes necrosis," Imperato said.

But it can result in amputations, and even death, 10 percent to 20 percent of the time.

As with the graduate student in Georgia, infections usually start with an innocuous-seeming cut or scrape or crush injury, which progresses to swelling and worse.

The good news is that these infections tend to respond well to a variety of antibiotics if they're given early enough. If drugs don't work, doctors will go in and remove the dead tissue, Imperato said.

If you're on a sports team, using alcohol-based gels and other hygiene precautions such as diligent hand-washing and not sharing towels will reduce the risk of necrotizing fasciitis, Bromberg said.

Any infection, however minor, which progresses and becomes red and swollen, especially if it's accompanied by diarrhea and vomiting, should be brought to a doctor's attention, Imperato advised.

More information

To learn more, visit the National Necrotizing Fasciitis Foundation.