Tokyo, Nov 9 (IANS): Japan's influenza cases have entered a nationwide outbreak phase, with cases continuing to increase across the country, government data showed.

For the week ending November 3, roughly 5,000 medical institutions reported a total of 5,127 influenza cases, an increase of 829 cases from the previous week, according to the country's Health Ministry.

The average number of patients per medical institution reached 1.04, surpassing the threshold for declaring the start of a nationwide flu season, prompting the ministry to announce the official onset on Friday, Xinhua news agency reported.

By region, Okinawa reported the highest flu incidence, with 10.64 cases per facility, followed by Shizuoka (2.09), Chiba (2.00), Oita (1.66), and Fukui (1.62).

Health officials urged the public to adhere to basic preventative measures, including frequent handwashing, appropriate mask use, and considering vaccination, particularly for high-risk groups.