Tokyo, Dec 17 : The average number of influenza patients per regularly monitored medical institution in Japan had hit warning levels at the fastest pace in 10 years, the health ministry has announced. About 5,000 such designated institutions across the country reported 166,690 flu cases in the week through December 10, averaging 33.72 people per facility and exceeding the warning level of 30, Xinhua news agency reported citing the Ministry of Health, Labor and Welfare as saying. The National Institute of Infectious Diseases estimated that the number of patients nationwide totaled around 1,118,000 during the seven-day period. While coronavirus cases in the period have also been increasing for the third consecutive week, experts here called for caution amid fears both viruses could spread further as year-end and New Year's social gatherings take place in the country. Influenza outbreaks typically occur in the winter and the end of spring, this year saw an unusual increase in cases from August. Further, the ministry cautioned against the flu in October when cases exceeded the advisory level for that month of 10 people per institution. "Individual measures for preventing infection are the same as those for Covid-19, including getting vaccinated, wearing masks, and avoiding crowded places," Nobuhiko Okabe, head of the Kawasaki City Institute for Public Health, was quoted as saying by the Japan Times. /IANS