Health officials racing to identify cause of rise in streptococcal toxic shock syndrome, which has a 30% fatality rate

Experts warn that a rare but dangerous bacterial infection is spreading at a record rate in Japan, with officials struggling to identify the cause.

The number of cases in 2024 is expected to exceed last year’s record numbers, while concern is growing that the harshest and potentially deadly form of group A streptococcal disease – streptococcal toxic shock syndrome (STSS) – will continue to spread, after the presence of highly virulent and infectious strains were confirmed in Japan.

The 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.”

Provisional figures released by the NIID recorded 941 cases of STSS were reported last year. In the first two months of 2024, 378 cases have already been recorded, with infections identified in all but two of Japan’s 47 prefectures.