Flesh-eating bacteria: what you need to know about Vibrio vulnificus and how to avoid it
In the wake of flooding from Hurricane Ian, Lee County, Florida experienced what the state Department of Health called an « abnormal increase » in cases of the rare bacterial infection.
Florida reported 64 Vibrio vulnificus infections and 13 deaths this year as of Friday, according to the health department, up from 34 cases and 10 deaths last year. It’s the first time the number of cases has topped 50 since 2008, when the state began tracking.
Many cases have been centered in Lee County, where residents cleaned up after Category 4 Hurricane Ian made landfall in late September.
These infections are rare but serious. Vibrio vulnificus causes approximately 80,000 illnesses and 100 deaths in the United States each year, according to the United States Centers for Disease Control and Prevention.
Vibrio vulnificus lives naturally in warm, salty or brackish water. It belongs to the same family as the bacteria responsible for cholera.
Vibrio can be found in waters around the world. In the United States, it lives in the Gulf of Mexico and along some of the coastal waters of the east and west coasts. The bacterium proliferates during the warmer months, when ocean temperatures are at their highest.
Infections can occur when a person comes into contact with water containing large amounts of bacteria or eats contaminated seafood.
A mild case of vibriosis usually includes chills, fever, diarrhea, stomach pain, and possibly vomiting. Usually people get sick on the first day of exposure to the bacteria.
Skin wounds infected with Vibrio vulnificus usually develop blisters, abscesses and ulcers.
Vibrio vulnificus is one of the bacteria that can cause what is commonly called a flesh-eating infection. Necrotizing fasciitis eats away at the skin, muscle, nerves, fat, and blood vessels around an infected wound.
In more severe cases, people can develop sepsis. This is more common in people with underlying health conditions, especially liver disease, cancer, diabetes, HIV or other diseases that weaken the immune system.
Sepsis occurs when the bacteria enters the bloodstream and spreads. It can cause fever, chills, low blood pressure, or blisters on the skin.
This can lead to septic shock, when blood pressure drops dangerously. The bacteria releases toxins into the bloodstream that could cause extremely slow blood flow, damaging tissues and organs.
It can also cause sepsis, in which the body mounts a strong immune response that shuts down important organs like the heart or kidneys. Or it can lead to acute respiratory distress syndrome, or ARDS, a condition in which oxygen from the lungs does not reach the blood. This can cause permanent brain damage and lung damage.
If the infection travels through the bloodstream, the consequences can be fatal.
Typically, the mortality rate is around 25% with wound infections, according to studies. It is much higher for people who are exposed to the bacteria by eating contaminated food.
Most Vibrio infections in the United States usually do not come from an infected wound, but from eating raw or undercooked seafood like oysters, especially during the summer months.
Bacteria can live in the bellies of fish, oysters and other shellfish. People can consume or be exposed to the bacteria when preparing raw seafood.
Vibrio vulnificus infection is the leading cause of death related to seafood consumption in the United States. Most of these cases involve primary sepsis or bacteria in the blood.
With skin infections, a doctor will first take samples from the infected area to determine if Vibrio vulnificus is the cause of the problem.
They will drain abscesses and treat the infected site, sometimes covering the wound with a topical antibiotic and skin protectant, in addition to other antibiotics. If there is necrotizing fasciitis, they may need to have surgery or even amputate the affected limb to prevent the infection from spreading.
Doctors say it’s important to get treatment quickly. People who see a doctor as soon as they notice an infection respond better to treatment, studies show, and their infections are less likely to become fatal.
However, this particular bacterium has developed some resistance to antimicrobials. According to studies, up to 50% of Vibrio vulnificus infections no longer respond to certain antibiotics.
The 28 cases of Vibrio infection associated with Hurricane Ian in Lee County, according to the health department, followed exposure to floodwaters that carried high concentrations of the bacteria into people’s homes. Some may have been exposed while cleaning up after the storm.
Six deaths due to Vibrio infection have been reported in Lee County.
While these infections are still rare, this isn’t the first time a hurricane has brought a small wave of cases. A spike came after Hurricane Katrina in 2005, according to the US Centers for Disease Control and Prevention, when people were also exposed to Vibrio vulnificus in floodwaters.
Scientists fear that infections will continue to rise with climate change. Warmer oceans create a more welcoming environment for bacteria and increase the frequency of hurricanes – and people’s exposure to floodwaters.
The only way to prevent Vibrio infection is to avoid exposure.
If you have a skin wound, even a new tattoo or piercing, doctors suggest you stay out of the ocean and avoid brackish water, or at least cover the area with waterproof bandages.
If exposed to salt water, the CDC advises you to wash your hands and any cuts thoroughly with soap and water afterwards.
If you must go into the water, such as for hurricane cleanup, wear clothing and shoes that protect against cuts or injuries from floodwaters.
You can also reduce your risk of vibriosis by making sure your seafood is cooked properly. Avoid raw or undercooked oysters or other shellfish, and be sure to wash your hands with soap and water after handling raw shellfish.
For cooked shellfish, eat only those that open during cooking. For shelled oysters, the CDC recommends boiling, frying, or grilling them for at least three minutes or baking them at 450 degrees for 10 minutes.