Japan's Tokyo metropolitan government has issued a warning following a significant increase in cases of a rare yet severe bacterial infection known as streptococcal toxic shock syndrome (STSS), local media reported on Monday.

The latest figures reveal that the number of cases has surpassed half of last year's count, reaching 88 cases in the capital alone, while nationwide infections stand at 517, according to The Japan Times.

STSS, often referred to as the flesh-eating disease and typically caused by group A streptococcus bacteria, can lead to tissue necrosis, with a mortality rate of around 30 percent of infected individuals in 2023, according to the Tokyo metropolitan government.

Tokyo had 88 patients as of March 17, the paper reported, citing a city meeting on infectious disease control last Friday. In 2023, the capital reported a total of 141 cases and 42 deaths linked to STSS infections.

Tokyo's authorities have urged individuals to seek immediate medical attention if they experience symptoms such as limb pain and swelling or fever, indicative of STSS infection.

Group A streptococcus can be transmitted through respiratory droplets and direct contact, as well as through wounds on the hands or feet. Health officials emphasize the importance of basic preventive measures such as frequent handwashing and proper wound care.

The rise in STSS cases is believed to be associated with a variant known as the M1UK strain, which has been increasingly detected in patients since mid-November 2023.

While individuals aged 40 and older have historically accounted for about 90 percent of cases each year in Tokyo, there was a notable increase in infections among individuals in their 40s in 2023, said the paper, citing the National Institute of Infectious Diseases.