Culturally verified Mycoplasma pneumoniae pneumonia in Japan: a long-term observation from 1979-99.

We describe the prevalence of community-acquired M. pneumoniae pneumonia diagnosed by culture methods in a single institute in Japan from January 1979 to December 1999. Cultures were performed in 2971 pneumonia cases and yielded M. Pneumoniae in 508 cases. The epidemic peaks recurred regularly at 4-year intervals (1980, 84, 88 and 91-2). Although a large epidemic has not occurred since 1992, traces of epidemic periodicity have still persisted from 1992 to 1999 at 3-year intervals.