The number of adults suffering from measles has risen sharply in recent months, with a Tokyo hospital reporting about 20 such cases in the last two months, according to officials at the Health and Welfare Ministry.

Medical institutions monitoring the disease have reported to the ministry that the number of people that have contracted measles since January total about 12,000, a threefold increase over the previous 12 months, the officials said.

Many reports came from Osaka, Chiba, Saitama and Kagawa prefectures, while most of those infected were in their 20s, they said.