TOKYO, April 14 (Xinhua) -- A total of 236 measles cases have been recorded in Japan since January, roughly 3.6 times the number for the same period last year, a national health research body said Tuesday.

According to the Japan Institute for Health Security, 34 cases were reported during the week through April 5. While the first 100 cases were confirmed in the period through March 8, the next 100 were logged in the four following weeks.

Japan was declared measles-free by the World Health Organization in 2015. Patients in Japan who have not traveled abroad are therefore believed to have been infected by a virus that was brought into the country.

The institute released a report this month analyzing the risks of measles, noting that reports of measles cases have been increasing worldwide since 2023, and that active international travel is making it more likely that the virus would be brought in from abroad.

The highest annual number of measles cases in Japan in the past decade was 744 in 2019, while 265 were recorded in 2025 on a provisional basis.