What is Vibrio Vulnificus and Should You Be Concerned?

Vibrio vulnificus, a deadly type of bacteria, is a growing threat to swimmers at Florida beaches. CDC/Janice Carr/dapd/AP

It's the stuff of nightmares: a type of bacteria that takes over and essentially eats a person alive.

But it's real. Last week, a 26-year-old man went for a swim at a beach in Florida's Hernando County and contracted a bacterial infection that killed him two days later. At least 10 people in the state have been infected with Vibrio vulnificus, and two have died this season after either swimming at a beach or eating raw shellfish that was contaminated with the bacteria.

Here's what you need to know about the scary but relatively rare illness.

What is V. vulnificus?

V. vulnificus is a bacterial microorganism that's from the same family as the type that causes cholera. It typically found in seawater. It is halophilic, which means it requires salt to survive and grow. It also needs warmer temperatures to thrive, which is why infections, known as vibriosis, are more common in the summertime.

How do you get it?

V. vulnificus can be both foodborne and waterborne. Most people will contract an infection after eating raw seafood that contains the bacteria (it's particularly prevalent in oysters). The infection can also occur when the bacteria enters the body through a cut or scrape in the skin, most likely by swimming in contaminated coastal water between 68 and 95 degrees Fahrenheit. The U.S. Centers for Disease Control and Prevention says there is no evidence of person-to-person contamination.

What are the symptoms?

In people with a healthy immune system, V. vulnificus causes vomiting, diarrhea and abdominal pain. Patients who are immunocompromised may develop a life-threatening infection of the blood stream with symptoms that include fever, chills, sepsis and skin lesions. Open-wound exposure to the bacteria may cause swelling, redness and pain near the wound. Symptoms typically begin one to three days after exposure.

An infection may lead to necrotizing fasciitis, where the bacteria destroys the skin and tissue covering the muscle. That's why in the popular media, the infection is sometimes referred to as flesh-eating bacteria. This, however, is not a medical term, and is also occasionally used to describe other bacteria that cause necrotizing fasciitis, including, for example, group A streptococci bacteria.

How many people contract it each year?

V. vulnificus is relatively rare, but health experts say incidences also tend to go unreported. According to the CDC's most recent data, there were more than 900 reported cases of vibriosis between 1998 and 2006 in the Gulf Coast region, including Alabama, Florida, Louisiana, Texas and Mississippi.

Who is at highest risk?

People who eat a lot of raw shellfish are at highest risk for gastrointestinal upset from V. vulnificus. A serious and potentially fatal bloodstream infection typically occurs in people with compromised immune systems or chronic diseases such as diabetes or HIV. According to the CDC, people with preexisting conditions are 80 times more likely to develop a bloodstream infection than people who do not have a preexisting condition.

How is a V. vulnificus infection treated?

Doctors typically treat an infection with common antibiotics such as doxycycline or cephalosporin. Severe infection will likely require amputation. A person who believes they've been exposed to the bacteria and has some symptoms—such as a sore or stomach upset—should see a doctor right away. Antibiotics are most effective if they're used right away.

What's the prognosis?

For the most part, a person who acquires an infection will recover and won't experience any lasting long-term effects. If an infection progresses to the bloodstream and causes skin ulcerations there is a potential to develop gangrene, or decomposition of body tissue, which may require skin-grafting or amputation. Approximately 50 percent of patients who develop a bloodstream infection will die, according to the CDC.

How can you prevent an infection?

The most surefire way to prevent an infection is to avoid eating uncooked shellfish, or at least consume shellfish from a reputable seller or restaurant. It may also be prudent to avoid swimming at the beach if you have an open cut or sore.