What is a streptococcal infection?

Streptococcal infections are spreading at a record pace in Japan: between January and March 2024, 422 cases were recorded (provisional figures) with infections identified in all but two of Japan’s 47 prefectures, compared to 941 in total over 2023, which was already a record, reports the National Institute of Infectious Diseases, the Japanese body responsible for health statistics. Normally, around 100 to 200 cases are counted each year in the Japanese archipelago. It is the most serious formlinked to a more virulent and transmissible strain of bacteria (probably from the line M1UK) which is mainly monitored by the health authorities: streptococcal toxic shock syndrome (SCTS), which has a 30% mortality rate and which would affect young people, under 50 years old.

“Severe and sudden fulminant forms of streptococcus”

“There are still many unknown factors regarding the mechanisms behind fulminant shapes (severe and sudden) streptococcus, and we are not at the stage where we can explain them“, underlines the Japanese daily Asahi shinbun. Some experts believe this rapid increase in cases could be linked to the lifting of restrictions imposed during the Covid-19 pandemic. In May 2023, the Japanese government downgraded Covid to level 5 of the national classification, that is to say at the same stage as seasonal flu. “This led more people to abandon basic measures to prevent infections, such as regular hand disinfectionexplains Ken Kikuchi, professor of infectious diseases at the Tokyo Medical University, to the British daily The Guardian. In my opinion, more than 50% of Japanese people have been infected with Sars-CoV-2. The immunological status of people after recovering from Covid-19 could modify their sensitivity to certain microorganisms. We need to clarify the infection cycle of serious invasive streptococcal pyogenic diseases and control them immediately.”

What is a streptococcal infection?

The term “streptococcal infection” refers to an infection caused by group A streptococcus (Streptococcus pyogenes). There are several types, more or less serious. Most of the time, this bacteria does not cause symptoms. In other words, the person is affected without knowing it and does not become ill. In some cases, the bacteria is called “opportunistic” and can cause mild infections such as strep throat or impetigo, according to thePastor Institute. Exceptionally and when not treated in time, this bacteria can lead to streptococcal toxic shock syndrome, due to the production of a toxin. It is a serious invasive infection with fatal visceral failure In 30% of cases. We must be reassured: in 80% of cases, the infection is non-invasive and benign, recalls the National reference center for streptococci.

At first: symptoms similar to a cold

The transmission of this bacteria is mainly interhuman and occurs through respiratory droplets, contaminated surfaces or through injuries to the hands and feet. This bacteria is contagious. When the bacteria causes a symptomatic infection:

► At first, the infection begins with mild, cold-like symptoms:

• Sore throat
• Runny nose
• Cough

► If the infection gets worseit can develop into streptococcal throat with symptoms:

• Red, painful tonsils
• High fever
• Headache
• Swollen lymph nodes in the neck

► In the most serious (exceptional) cases, it can lead to streptococcal toxic shock syndrome:

• Hypotension
• Confusion
• Severe diarrhea
• Vomiting
• Organ failure that can lead to pneumonia or meningitis
• Kidney damage
• Liver damage

Should we be worried in France?

According to the National Institute of Infectious Diseases, patients under 50 years old appear to be most at risk of developing a severe form. “The reasons for a severe streptococcal A infection are poorly understood. A transient or permanent deficiency of the immune system is suspected.“, explains Professor Antoine Flahault, professor of public health and epidemiologist at the University of Global Health of Geneva in Actu.fr. The epidemiologist nevertheless wants to be reassuring: “Streptococcus A has existed since the dawn of time and the epidemics that we can observe here and there, as currently in Japan, are not exceptional.“, he believes.

No link between the unusual increase in cases in France and the current situation in Japan.

>> In France: these invasive infections have been increasing since 2000, the incidence rate having increased from 1.2 to 3.3/100,000 people (figures from the Pasteur Institute), but there is no no unusual epidemic phenomenon according to health authorities. And an increase in invasive Group A Streptococcus infections has been observed in children under 10 years old since the end of 2022 in different French regions (Occitanie, Auvergne-Rhône-Alpes, New Aquitaine). Public Health France reported 19 deaths in France. This “epidemiological situation is not linked to the emergence of a new bacterial strain”, informed the health agency. There would therefore be no link between this unusual increase in cases in France and the situation in Japan.

Is it treatable?

► Mild streptococcal infections are treated with antibiotics.

► Serious streptococcal infections such as streptococcal toxic shock syndrome require a combination of antibiotics and other medications (often drugs that increase blood pressure), as well as intensive medical care. There does not exist no vaccine to protect against group A streptococcal infection.