KNOXVILLE, Tenn. – Several cases of flesh-eating bacteria, otherwise known as necrotizing fasciitis, have put people in hospitals across the United States and killed some.
A Memphis, Tennessee, man died last week after contracting the flesh-eating bacteria, vibrio vulnificus, while on vacation in Destin, Florida.
So, just how common is this, and should you be worried about swimming in oceans, rivers or lakes?
Are flesh-eating bacteria on the rise?
Mark Rasnake, an infectious disease physician at the University of Tennessee, said the Centers for Disease Control and Prevention has not issued any reports confirming a rise in cases of flesh-eating bacteria this year.
"I sort of think it's just one of those things that's maybe amplified by social media," Rasnake said.
Necrotizing fasciitis is the death of the deep tissue, and multiple types of bacteria can become "flesh-eating," including group A Streptococcus, which causes sore throats but is not associated with water, according to Rasnake.
The CDC tracks necrotizing fasciitis in the U.S. caused by Group A Strep. Its website reports that since 2010, there have been approximately 700 to 1,200 cases of necrotizing fasciitis annually in the country, which " is likely an underestimate."
About one in three people die from the infection, according to the CDC.
What you need to know about Vibrio: Maryland boy infected with flesh-eating bacteria.
Twenty to 30 types of bacteria can be a source, according to Rasnake.
The bacteria associated with saltwater and from eating raw oysters is Vibrio vulnificus, while the bacteria found in freshwater sources like the Tennessee River is Aeromonas.
Vibrio vulnificus and Aeromonas are naturally occurring in warmer waters. Rasnake said July and August are the months when the chance of contracting the bacteria goes up as the bacteria and the number of people enjoying the water increase.
In Virginia, health officials are issuing warnings about Vibrio parahaemolyticus, also a flesh-eating bacteria.
So far this year, nine have contracted the infection in the region and one person has died. According to the Virginia Department of Health, Vibrio parahaemolyticus is the most commonly reported type of Vibrio infection in that state. The number of cases tends to increase between April and October due to warmer seawater temperatures.
'The bacteria had destroyed him': Man dies after being infected by flesh-eating bacteria in Florida
How to avoid it, know its symptoms
While rare, some people are more susceptible than others to getting necrotizing fasciitis, according to Rasnake. Individuals with other illnesses and health problems that can lower the body's ability to fight infections like diabetes, kidney disease, scarring of the liver and cancer, are more likely to contract it.
"I don't think people need to be afraid of the lakes or rivers or oceans, as long as they are otherwise healthy and don't have open wounds, I don't think there's any particular risk to most people," Rasnake said.
If someone has an open wound, he or she should avoid going in the water. However, if you happen to scratch your leg on a broken shell while in the water, for example, look for certain symptoms to know if you possibly have contracted bacteria.
Flesh-eating bacteria: She died of flesh-eating bacteria after a beach trip. Now her family wants to warn others
Early symptoms, according to the CDC, are red or swollen areas on the skin that spread, fever and severe pain that isn't just in the area of the wound. If these symptoms are present, it is advised to go to the hospital.
Other symptoms include ulcers, blisters or black spots, pus or oozing from the wound, dizziness, fatigue and diarrhea or nausea.
In the worst-case scenarios, Rasnake said patients can lose entire limbsor die if the bacteria isn't caught early enough. If diagnosed early, patients can receive antibiotics, although it can still be difficult to treat.
The Tennessee Department of Environment and Conservation monitors bacteria levels in hundreds of locations across Tennessee and uses E. coli as an indicator for the presence of bacteria, following the federal Environmental Protection Agency's guidelines for which contaminants are monitored routinely.
Deputy Communications Director of TDEC Kim Schofiniski said the public should follow all posted bacteriological and fish consumption advisories to avoid contracting any bacteria.
No swimming! No seafood! Toxic bacteria afflicting coast causes rashes, diarrhea, vomiting
Is flesh-eating bacteria contagious?
Most cases of necrotizing fasciitis occur randomly, according to the CDC's website.
It is very rare for someone to spread the infection to other people.
"For this reason, doctors usually do not give preventive antibiotics to close contacts of someone with necrotizing fasciitis," according to the CDC.
Moving North as the climate warms
Since the bacteria live in warmer waters and there has been an increase in ocean temperatures, Rasnake said he expects the bacteria to be found further North.
"As ocean temperatures warm in places where that bacteria did not live before, they start to multiply ... you can certainly start to see more cases in parts of the country that you hadn't seen necessarily seen before, like the northeastern beaches," Rasnake said.
Combined with an aging population that is living longer and more people taking immunosuppressive medications, the number of cases could increase, he said.
Climate change to blame? A rise in cases of flesh-eating bacteria may be linked to climate change, doctors say
Contributing: USA TODAY
This article originally appeared on Knoxville News Sentinel: Here's how you avoid contracting 'flesh-eating' bacteria