Japan has an outbreak of "man-eating bacteria" infection with a mortality rate of up to 30%. Do bacteria really eat people?

"A new deadly infectious disease with a high mortality rate broke out in Japan, 'Man-eating bacteria infection'? "

Recently, the "man-eating bacteria infection" has caused heated discussions on the Internet, and many news reports claim that Japan is being ravaged by "man-eating bacteria". Many friends think that this is some new deadly infectious disease and are very worried about it.

Rumor Analysis

This statement is not correct.

This disease is not a recent phenomenon, nor is it caused by a new pathogen. Although the common name "man-eating bacteria infection" is scary, it is actually streptococcal toxic shock syndrome (STSS). Healthy people are not prone to this syndrome, but for the elderly and people with poor immune system function, if infected, it may indeed cause risks, so we must also understand this disease and develop good hygiene habits to prevent it.

What is "Man-eating Bacteria Infection"? How can we prevent it? Let's talk about it in detail.

Picture from Weibo

What are man-eating mushrooms?

According to statistics released by the National Institute of Infectious Diseases of Japan on June 18, as of June 9, the number of cases of streptococcal toxic shock syndrome (also known as "man-eating bacteria" infection) reported in Japan this year has exceeded 1,000, reaching 1,019. What kind of rare species is this bacteria, which is called "man-eating bacteria" in Japan? Can it really eat people?

In fact, the so-called "man-eating bacteria" are not rare at all. They belong to the hemolytic streptococcus family and often cause health problems for humans. There are many types of hemolytic streptococci, among which type A hemolytic streptococci (GAS) are mostly streptococci pyogenes, which are the main pathogens causing many diseases, including pharyngitis, scarlet fever, streptococcal skin infections (such as impetigo and erysipelas), acute rheumatic fever, and streptococcal toxic shock syndrome.

In addition to type A hemolytic streptococci, there are also type B (GBS) and type C and G. Among them, type B hemolytic streptococci (GBS) mainly cause serious infections in newborns, including sepsis, pneumonia and meningitis. Adults, especially the elderly or those with weakened immune systems, may be infected with GBS, leading to urinary tract infections, skin infections and sepsis. Although type C and G hemolytic streptococci are not as common as type A and type B streptococci, these streptococci can also cause throat infections, skin infections and invasive diseases.

Streptococcus pyogenes that causes the disease (Source: Wikipedia)

These germs are mainly spread through droplets and contact. When the bacteria enter tissues such as blood or muscle, they may cause serious infection. The initial symptoms of the disease include fever and chills. Rapid infection may cause: liver failure, kidney failure, acute respiratory distress syndrome, disseminated intravascular coagulation, soft tissue inflammation, systemic erythematous rash and central nervous system symptoms, and even death. According to reports, the infected are usually elderly people or individuals with weak immune systems, and the mortality rate is as high as 30%.

Do man-eating mushrooms really eat people?

Bacteria are tiny and have no teeth, so they certainly can’t “eat people” the way we eat food. The reason why hemolytic streptococci are called “man-eating bacteria” is actually an exaggeration, mainly because the streptococcal toxic shock syndrome (STSS) it causes has an extremely high mortality rate and rapid tissue destruction.

When this bacteria infects the human body, it first enters the body through damaged skin or mucous membranes, then destroys host tissues by secreting a variety of enzymes and toxins to evade the attack of the immune system. The bacteria and their toxins can enter the blood and cause systemic infection in a short period of time, leading to severe inflammatory reactions, multiple organ failure, and severe muscle and skin necrosis, as if "devouring" the human body.

This time, Japan's "man-eating bacteria" infections have surged, with a total of 941 cases in 2023, and 851 cases reported as of May 2024, 2.8 times the same period in 2023.

As of March 25 this year, the infection situation of "man-eating bacteria" in Japan (Source: National Institute of Infectious Diseases, Japan)

In addition to Japan, from late 2022 to early 2023, the United Kingdom, France, Ireland, the Netherlands, Sweden and other places reported an increase in STSS infections, especially in children under 10 years old, and the number of reports of the M1UK strain of STSS also increased. STSS infections in these countries stabilized around April 2023, but the situation varied thereafter. For example, the United Kingdom has not had any abnormalities since February 2023, while Sweden saw an increase in STSS infections again in the second half of 2023, mainly in the elderly over 70 years old.

The United States also reported an increase in STSS infections in children in December 2022, and the Centers for Disease Control and Prevention subsequently issued a warning, but no further increase was seen. In contrast, Canada has not reported a national outbreak, but British Columbia has seen an increase in STSS infections in children under 20 years old since December 2023. Australia began monitoring STSS infections in 2021, and the number of reports has gradually increased.

In Argentina, there was an increase in STSS infections and deaths among children in 2023. Most of the strains analyzed were of the M1(emm1) type, of which 9.1% were of the M1UK lineage.

How does "man-eating bacteria" spread?

How should it be prevented?

The transmission modes of man-eating bacteria that cause STSS can be divided into the following categories:

1

Droplet transmission

Streptococcus is spread through airborne droplets, which are tiny droplets produced when an infected person coughs, sneezes or talks. This is one of the main ways that strep is spread.

2

Direct contact transmission

Bacteria can more easily enter through direct contact with an infected person's skin or mucous membranes, especially if there are cuts or breaks.

3

Indirect contact transmission

Touching objects contaminated by an infected person, such as towels, door handles, medical equipment, etc., and then touching your own mouth, nose, eyes, etc., may also lead to infection.

It is also important to prevent infection from "man-eating bacteria", including the following measures:

1

Personal Hygiene

Maintaining good personal hygiene is key to preventing STSS. Wash your hands frequently, especially after touching shared objects, treating wounds, or working in a healthcare setting. Wash your hands thoroughly with soap and running water for at least 20 seconds, or use an alcohol-based hand sanitizer.

2

Protecting skin and wounds

Any skin injury, including minor cuts, scrapes and insect bites, should be cleaned, disinfected and covered with a dressing. Avoid scratching the wound to prevent bacteria from entering. Keeping the wound dry and clean can reduce the risk of infection.

3

Avoid close contact

Try to avoid close contact with people who have streptococcal infection, especially when they cough and sneeze. Infected people should wear masks and avoid sharing dishes, towels and bedding with others. If there is an infected person in the family, the family should strengthen cleaning and disinfection.

4

Seek medical attention promptly

If you experience symptoms of infection such as fever, chills, redness, swelling, and pain on the skin, you should seek medical attention immediately, especially if you are in a high-risk group such as the elderly, people with weakened immune systems, or people with chronic diseases. Early diagnosis and treatment can effectively reduce the severity and mortality of STSS.

In short, strengthening personal protection and hygiene habits are the key to preventing infection from "man-eating bacteria". For the elderly and those with weak immunity, they need to be especially vigilant and take extra precautions. However, there is no need to panic. For ordinary people with good health and intact skin, even if they are infected, it is not easy to develop into a serious illness.

Looking in the mirror of rumors

Sometimes, we may give something a resounding "nickname", which is often sensational and can attract attention and traffic, but often exaggerates a certain feature of it, making people ignore the essence of the thing, just like the so-called "flesh-eating bacteria" that has been widely circulated this time. As long as we have a deeper understanding of it, many unnecessary panics will be shattered.

Planning and production

Author: Denovo, PhD in Analytical Chemistry

Review丨Zhang Yu, researcher/PhD, Chinese Center for Disease Control and Prevention, national health science expert

Planning丨Ding Zong

Editor: Ding Zong

Proofread by Xu Lai, Lin Lin

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