Epidemic patterns of infectious diseases from the results of the surveillance of infectious diseases in Japan.

Epidemic patterns of 12 infectious diseases based on the data derived from the surveillance system of infectious diseases in Japan are analyzed. Weekly numbers of patients per one monitor station (general clinics and hospitals) are calculated by prefecture. Based on these data, the patterns of epidemic are classified into five categories: Category 1, nationwide outbreak of short duration (rotavirus enteritis, hand-foot-mouth disease and herpangina); Category 2, nationwide outbreak of long duration (varicella); Category 3, concurrent outbreaks in several districts (rubella and erythema infectiosum); Category 4, epidemic of long duration in several prefectures at different times (measles, mumps, pertussis, streptococcal infection and atypical pneumonia); Category 5, unclear epidemic pattern (exanthema subitum).