The number of measles cases in Japan since the start of the year has grown at its fastest pace in the past decade, with Mie Prefecture leading the increase.
The National Institute of Infectious Diseases said Tuesday that 167 new measles patients were reported in 20 of the nation’s 47 prefectures between the start of 2019 and Feb. 10.
The health ministry has issued a notice calling on medical institutions to take preventive measures against the highly infectious disease.
The institute said Mie saw 49 new measles patients during the period, followed by 47 reported in Osaka Prefecture, 17 in Aichi Prefecture, 11 in Tokyo and six in Kanagawa Prefecture, south of Tokyo.
According to the Mie Prefectural Government, of 49 people who participated in a seminar held by a religious group late last year at a facility in Tsu, the capital of the prefecture, 29 have been diagnosed with measles.
Of the 29 patients, 24 came from Mie, three from Gifu Prefecture and one each from Aichi and Wakayama prefectures. The disease spread to their family members and those who had contact with those infected at medical institutions and schools.
In the city of Osaka, 12 employees at the Abeno Harukas commercial complex of Kintetsu Department Store Co. and 11 customers had been diagnosed with measles or were suspected of having measles as of Wednesday.
The Osaka Prefectural Government said a woman in her 40s infected with measles traveled between Tokyo Station and Shin-Osaka Station and back via the Shinkansen bullet train on Feb. 8 and Feb. 10. The authority warned that the disease may have been spread to an unspecified number of people.
After a latent period of some 10 days, the disease causes symptoms including fever, cough and a runny nose, which are followed by skin rashes. While patients normally recover in seven to 10 days after the symptoms appear, some may develop complications such as pneumonia and inflammation of the brain.
Receiving a vaccination twice is said to be effective in preventing measles. Over 95 percent of Japanese aged 2 or older have antibodies against the disease, a source said.
A ministry official said a large measles outbreak is unlikely, but called on people to consult with doctors quickly if they suspect they are experiencing any of the known symptoms.