SINGAPORE – The US Centres for Disease Control and Prevention (CDC) on Sept 1 warned about a flesh-eating Vibrio vulnificus, following recent reports of fatal infections of the bacterium.

At least six people have died from the bacterium in the United States’ east coast this summer, according to US media.

The Straits Times reported in September that an American woman lost all four of her limbs after suffering a bacterial infection from eating what was believed to be undercooked fish, although some US media reports later stated that she did not test positive for Vibrio vulnificus.

ST looks at how common Vibrio vulnificus is in Singapore, and how people can protect themselves against it.

Q: What is Vibrio vulnificus?

A: Vibrio vulnificus is a bacterium that lives in warm seawater and is concentrated in sea animals such as oysters and shellfish, according to the US CDC.

People can be infected with Vibrio vulnificus by consuming raw or undercooked seafood or exposing a wound to seawater, the CDC said.

Dr Shawn Vasoo, clinical director of Singapore’s National Centre for Infectious Diseases, said those who are infected with Vibrio vulnificus may suffer from septicaemia, commonly known as blood poisoning, and severe skin or soft tissue infection, also known as necrotising fasciitis.

A patient may survive with early treatment such as antibiotics and surgery, he added. If any infection is established, a patient may suffer loss of limbs or require major surgery to remove damaged tissue.

Q: Who is at risk of getting the infection?

A: Vibrio vulnificus typically occurs in people who have poor immune systems or liver disease, and are exposed to seawater, Dr Vasoo said.

The bacterium may also enter a person’s body through injuries such as cuts, and even pricks when preparing seafood, or people who eat undercooked seafood such as oysters, he added.

“Older men seem to be more affected than women,” Dr Vasoo said.

According to the CDC, about 150 to 200 cases of the infection are reported each year in the US, and around one in five people with the infection dies within one or two days of falling ill.

Q: Are there local cases of the infection?

A: Dr Vasoo said that while Vibrio vulnificus is not a reportable infectious disease here, there have been a few local cases noted in medical journals. A reportable infectious disease is one that must be reported to the Ministry of Health once diagnosed by a doctor or confirmed in a laboratory.

For instance, a 2005 local medical journal reported that a 37-year-old Chinese man had his right leg amputated below the knee after he ate raw cockles.

The man, who had liver disease, had then also recently injured his right foot while getting out of a truck.

Although X-rays did not show any fractures, blisters and early gangrene were observed on his right leg two days after he was admitted to the hospital.

The man subsequently underwent the amputation and was discharged after two months.

In a more severe case, a 66-year-old Chinese man died from Vibrio vulnificus septicaemia in 1986 just a few days after he complained of fever and chills.

A local medical journal in 1988 reported that the man’s swollen left leg turned gangrenous the next day. He also had diabetes mellitus and alcoholic liver disease. Doctors noted that his right leg had areas of ischaemia, a condition where blood flow and oxygen are restricted or reduced in a part of the body.

Both his legs were then amputated above the knee, but the man died several days later.

Q: How is the bacterial infection treated?

A: Antibiotics and surgical treatment are used to treat the infection, said Dr Vasoo.

In the case of skin and soft tissue infection, surgeons may have to perform emergency surgery to remove dead or damaged tissue, he added.

Dr Vasoo said: “Without early treatment, Vibrio vulnificus is severe and can lead to death once infection is established.”

Q: How can I protect myself against the infection?

A: Dr Vasoo said that people with liver disease or a weakened immune system should avoid eating raw seafood.

They should also avoid activities involving raw seafood, such as food preparation, which may lead to injuries such as pricks and cuts, he added.

Such people should be very careful and take precautions, like using cut-resistant gloves, if they have to deal with raw seafood.