Japan experiences significant surge in cases of potentially lethal bacterial disease.
As of June 2, the Japanese Health Ministry has reported 977 instances of streptococcal toxic shock syndrome (STSS), which carries a mortality rate of up to 30%. Between January and March, 77 deaths were recorded due to this infection.
These numbers exceed last year's previous high of 941 preliminary infections, making it the highest since records have been kept in 1999. The National Institute of Infectious Diseases in Japan reported 97 STSS-related deaths last year, the second-highest number of fatalities in the past six years.
STSS is a serious bacterial infection that can arise when bacteria penetrate deep tissues and the bloodstream. Initial symptoms include fever, muscle pain, and vomiting, but they can quickly escalate to life-threatening conditions such as low blood pressure, swelling, and multiple organ failure as the body goes into shock.
Approximately three out of every ten individuals diagnosed with STSS may succumb to the infection, as reported by the US Centers for Disease Control and Prevention (CDC).
Most STSS cases stem from the group A streptococcus (GAS) bacteria, typically responsible for childish fever and throat infections. Rarely, strep A can become invasive, producing a toxin that grants it access to the bloodstream, leading to severe illnesses like toxic shock.
Strep A can also cause necrotizing fasciitis, often referred to as "flesh-eating," potentially resulting in limb loss. However, individuals with underlying health issues, such as cancer or diabetes, are more likely to contract this disease, according to the CDC.
The pandemic's COVID-19 controls, like masking and social distancing, largely curtailed invasive group A strep infections. Yet, following the relaxation of these measures, several countries reported an upswing in cases.
In December 2022, five European countries informed the World Health Organization of an increase in invasive group A streptococcus (iGAS), with children under the age of ten being the most affected. The CDC was also conducting an investigation into what seemed to be an increase in the disease at the time.
In March, Japanese authorities issued a warning about a spike in STSS cases. The National Institute of Infectious Diseases released a risk assessment stating that the number of STSS cases caused by iGAS has increased since July 2023, notably among those under 50 years old.
The CDC advises that older individuals with open wounds are at a higher risk of contracting STSS, including those who have recently undergone surgery.
However, experts are uncertain about the origin of bacteria in nearly half of individuals diagnosed with STSS, as stated by the CDC on its website.
The cause for this year's increase in STSS cases in Japan remains unclear, according to Japanese public broadcaster NHK.
Professor Ken Kikuchi, from Tokyo Women’s Medical University, suggested to NHK that the increase could be due to weakened immune systems as a result of COVID-19.
"Our immunity can be boosted through constant exposure to bacteria. But that mechanism was absent during the coronavirus pandemic," Kikuchi explained. "So, more people are now susceptible to infection, and that may be one reason for the sharp rise in cases."
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The global health community is closely monitoring the situation in Japan, as the country grapples with an unprecedented rise in STSS cases. Various parts of the world, including Asia, have reported a surge in invasive group A streptococcus (iGAS) infections, highlighting the need for international collaboration in addressing this health concern.
