According to provisional figures from the National Institute of Infectious Diseases, there were 941 hemolytic streptococcus cases reported nationwide last year. The number of patients has continued to increase this year, reaching 378 as of Feb. 25. Cases have been confirmed in 45 of Japan's 47 prefectures, with only Akita and Iwate recording zero. Group A hemolytic streptococcus, which causes sore throats mainly in children, is a representative example among several pathogenic bacteria. Although infections often present similar symptoms to a cold, in rare cases and regardless of age, they can escalate to severe conditions including strep throat, tonsillitis, pneumonia and meningitis. Once the infection becomes acute, it can cause multiple organ failure and necrosis in tissue surrounding the muscles. According to the health ministry, it is unknown how infections escalate. However, the prevalence of sore throats among children since last summer is cited as a contributing factor in the increase in severe cases. Additionally, strains within Group A streptococcus known for their high pathogenicity, already widely reported in Britain, have also been confirmed domestically. In January, the ministry asked local governments to analyze strains collected from acute cases.