[Distributions of the numbers of monitoring stations in the surveillance of infectious diseases in Japan]. 
To describe the characteristics of monitoring stations for the infectious disease surveillance system in Japan, we compared the distributions of the number of monitoring stations in terms of population, region, size of medical institution, and medical specialty.  The distributions of annual number of reported cases in terms of the type of diseases, the size of medical institution, and medical specialty were also compared.  We conducted a nationwide survey of the pediatrics stations (16 diseases), ophthalmology stations (3 diseases) and the stations of sexually transmitted diseases (STD) (5 diseases) in Japan.  In the survey, we collected the data of monitoring stations and the annual reported cases of diseases.  We also collected the data on the population, served by the health center where the monitoring stations existed, from the census.  First, we compared the difference between the present number of monitoring stations and the current standard established by the Ministry of Health and Welfare (MHW).  Second, we compared the distribution of all medical institutions in Japan and the monitoring stations in terms of the size of the medical institution.  Third, we compared the average number of annual reported cases of diseases in terms of the size of medical institution and the medical specialty.  In most health centers, the number of monitoring stations achieved the current standard of MHW, while a few health centers had no monitoring station, although they had a large population.  Most prefectures also achieved the current standard of MHW, but some prefectures were well below the standard.  Among pediatric stations, the sampling proportion of large hospitals was higher than other categories.  Among the ophthalmology stations, the sampling proportion of hospitals was higher than other categories.  Among the STD stations, the sampling proportion of clinics of obstetrics and gynecology was lower than other categories.  Except for some diseases, it made little difference in the average number of annual reported cases of diseases in terms of the type of medical institution.  Among STD, there was a great difference in the average number of annual reported cases of diseases in terms of medical specialty.