Warnings of possible influenza outbreaks have been issued to all but one prefecture nationwide, a center on infectious diseases said Wednesday.
Serious warnings have been issued this week for 26 prefectures.
According to the Infectious Disease Surveillance Center of the National Institute of Infectious Diseases, only Okinawa Prefecture remains unaffected by possible epidemics, the center said.
In the 26 prefectures that have received serious warnings, including Hokkaido, Tokyo, and Osaka, a flu epidemic has already taken hold and is set to spread, the center said.
The 20 other prefectures have received less serious warnings, meaning an epidemic could possibly break out within the coming four weeks, it said.