Japan warns of huge unexplained spike in deadly strep cases

Japanese health authorities have warned about a sharp increase in potentially fatal strep infections, particularly in Tokyo where cases have tripled in a year.

As of 10 March, there have been 474 cases of the more severe streptococcal toxic shock syndrome (STSS), which can have a mortality rate of up to 30 per cent, according to a health ministry report.

Across the country, cases of throat infections caused by the streptococcus bacteria have quadrupled over the past five years. STSS occurs when the infection spreads throughout the body, potentially causing organ failure.

Unlike respiratory illnesses such as pneumonia or Covid-19, strep throat is not likely to lead to a pandemic situation, Dr Hitoshi Honda, an infectious diseases professor at Fujita Health University was quoted as saying by Reuters.

“This is a droplet infection,” he said. “Hand hygiene is extremely important for preventing invasive streptococcal infections.”

The surge in cases has even affected international events, as the North Korean soccer team abruptly cancelled a World Cup qualifier match in Japan due to the outbreak.

Since its identification in the country in 1992, there has typically been an average of only 100-200 cases per year of STSS. However, in 2019, this figure skyrocketed to a record high of 894 cases.

STSS is primarily caused by streptococcus pyogenes, commonly referred to as strep A, which can lead to sore throats, particularly in children, although many individuals can carry it without experiencing illness.

Earlier this month, Japan’s National Institute of Infectious Diseases [NIID] said: “There are still many unknown factors regarding the mechanisms behind fulminant (severe and sudden) forms of streptococcus, and we are not at the stage where we can explain them.”

Although older people are generally considered at higher risk, the group A strain of streptococcus bacteria is causing more deaths among patients under 50, according to the NIID.

According to Asahi Shimbun, between July and December last year, 65 people under 50 were diagnosed with STSS and approximately one-third, or 21, of them succumbed to the illness.

Ken Kikuchi, a professor of infectious diseases at Tokyo Women’s Medical University, told the Guardian earlier this month that he was “very concerned” about the significant increase this year in the prevalence of severe invasive streptococcal infections.

He believes that the reclassification of Covid-19 was the primary catalyst for the surge in streptococcus pyogenes infections. He also noted that this prompted more people to neglect fundamental infection prevention practices, such as regular hand disinfection.

“In my opinion, over 50 per cent Japanese people have been infected by Sars-CoV-2 [the virus that causes Covid-19]. People’s immunological status after recovering from Covid-19 might alter their susceptibility to some microorganisms. We need to clarify the infection cycle of severe invasive streptococcus pyogenes diseases and get them under control immediately.”