The International Tuberculosis Information Center (ITIC) was established in 1992 in order to collect information on tuberculosis epidemiology and on tuberculosis control programme from the countries in the world, analyze and feedback them. In ITIC computerized database system and library of references are maintained. Regarding information for the Western Pacific Region where Japan is a member country, ITIC has been collaborating with Regional Office for the Western Pacific, WHO.
As feedback activities, ITIC has information service through publications,such as Tuberculosis Statistics in the World and Epidemiological Review of Tuberculosis in the Western Pacific Region, and through providing information to inquiry.
The Computerized Tuberculosis Surveillance System in Japan
The computerized tuberculosis surveillance have been carried out since 1987 in Japan. The surveillance system consists of a three-phase structure,the health center level, the local government level, and the Ministry of Health and Welfare (MOHW).
MOHW is technically strongly supported by the Research Institute of Tuberculosis (RIT), Japan Anti-Tuberculosis Association (JATA), as can be seen in the Figure.
As of 1994, there are 844 health centers, 47 prefectures and 12 Metropolitan Cities as local government in Japan.
The individual data consist of the items such as sex, age, occupation of the patient, present bacteriology and X-ray findings and those at the time of registration, chemotherapeutic regimen, date of negative conversion and so on, which are recorded at each health center by the clerk, public health nurse or someone else. The individual data on the newly registered in the course of a month are to be accessed and sent to the local government by 10th of the following month, on-line. The local government should send the individual data to MOHW before 15th, on-line.
The results of the analysis are sent back to the local health center through local government up to 20th on-line. Results are distributed to the public through the monthly official journal of the Japanese Society for Tuberculosis, "Kekkaku".
The results of the analysis of the registered patients are published as “Tuberculosis Year Book”. A total of 50 tables including the distribution of patient's, doctor's and total delay, of initial chemotherapeutic regimen, and of the duration of hospitalization; chemotherapy and registration; treatment results and so on, are included in the routine analysis at national level.
As the Directors of every health center have the direct responsibility for tuberculosis control measures in the area, the analysis of data collected at the health center level is very important. For this purpose, 43 programs to be used for analysis are prepared at each health center. Programs for printout of special cases such as bacteriologically positive cases for one year or more after registration, registered 5 years earlier or more,and so on, are included. Analysis of the patient's, doctor's and total delay, analysis of treatment duration can be also done with the program available at the health center.
Further analysis of the collected data is carried out at prefecture level by the 50 programs already distributed to the local government to support the health center activities.
Precise analysis of the collected data is to be conducted at the RIT, JATA. The National Tuberculosis Surveillance Committee is organized by tuberculosis specialists and a committee meeting is to be held at any time if needed.
Tuberculosis case notification in the world
WHO has been collecting information on tuberculosis notification from the countries in the world. Here you can see tuberculosis case notification rates (rate: annual number of newly notified cases per 100 ,000 population)in several countries by region, which are derived from Tuberculosis - A Global Emergency: Case Notification Update, February 1996, Global Tuberculosis Programme, WHO, Geneva.
We need to understand the following issues when we see data:
1. Definition of notified tuberculosis cases may be different from country to country. For instance, notified tuberculosis cases include pulmonary cases but not extrapulmonary cases in some country.
2. Number of notified cases might be influenced by quality of diagnosis and reporting activities. For instance, cases diagnosed and treated in private sector are not included in official statistics in most developing countries.
Because of nature of these conditions, it should be considered that tuberculosis statistics bases on notification may not precisely reflect actual epidemiological situation of tuberculosis in some occasion. For instance, even if number of tuberculosis shows increase trend, it should be taken into consideration that the increase trend does not necessarily indicate worsening epidemiological situation and that it may just attribute to improvement of diagnosis and reporting activities in some countries. Therefore we call data shown here as case notification rate, not as incidence rate, which usually refers to rate of new cases occurring actually and which is the term used for theoretical discussion.