For planning and implementation of effective national tuberculosis control programme (NTP) in Ethiopia, it is essential to know the real magnitude of tuberculosis problem. Previous tuberculin survey carried out during the period from 1953 to 1955 revealed the annual risk of infection 3.0%, and since then, there has been no survey. A new tuberculin survey was thus conducted during the period from December 1987 to April 1990.
In order to get a sample of 47 previously BCG unvaccinated children, aged 6 to 10 years, selected from each 480 representative clusters of randomly selected 16 Woredas (districts), a total of 26, 529 children, approximately 55 in each cluster, were given tuberculin intradermal injection, and the reaction was read in 26, 269 children (99.0%). A scar survey was done, and 23, 695 had no BCG scar, while 2, 574 (10.1%) had BCG scar. Out of the former, 2, 503 children (10.6%) were positive, and the annual risk of infection thus calculated was 1.4%. Out of the latter, 591 (23.0%) were positive.
The results of these two surveys indicate that tuberculosis showed decline in the past 37 years with the annual reduction rate of 2.2%, however, the trend might change in the future due to present pandemic of HIV infection.

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A clinical study of 52 patients diagnosed as having pulmonary tuberculosis at National Chiba-Higashi Hospital between 1988 and 1990 was performed. The cases ranged in age from 80-89 years; mean male patient age was 82.5, and mean female patient age was 84.3. Diagnosis of the cases were as follows: 19 discovered when checking into hospital because of chest symptoms; 14 diagnosed during the treatment of other diseases; 14 diagnosed during admission to the hospital for other diseases; and five cases were detected by chest X-rays.
A total of 38 cases, had received primary treatment for pulmonary tuberculosis, 11 cases had received secondary treatment, and three cases were receiving treatment for tuberculosis. Upon admission to the hospital after the detection of tuberculosis, 19 cases tested positive to sputum smear examinations, six cases tested positive to culture examinations but negative to smear examinations, and culture examinations were negative in 27 cases. Regarding the chest X-ray findings, using the criterion of roentgenological classification for pulmonary tuberculosis established by the Japanese Society for Tuber culosis, two cases revealed type I, 29 cases revealed type II, and 21 cases revealed type III. Cavitary cases were observed in 60% of the chest X-ray findings. Upon hospital admission, 18 cases were observed to have circulatory diseases, 16 cases had central nervous diseases, 12 cases had digestive diseases and 11 cases had respiratory diseases. Nine cases had malignant neoplase, five cases had diabetes mellitus and 14 cases had other diseases.
A total of 18 cases ended in death; six cases died of pulmonary tuberculosis, and 12cases died of other diseases. It was concluded that most of the cases were progressive and a number of other diseases added complications. It is therefore important that tuberculosis be detected in the early stage for elderly persons, and treatment initiated immediately.

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A 67-year-old man was admitted to our hospital because of cough and sputum. Chest X-ray revealed cavity and consolidation in the right upper lobe. Microscopical examination of stained specimens of sputum disclosed acid-fast bacilli (Mycobacterium tuberculosis). Cough and sputum resolved and cultures of sputum did not yield M. tuberculosis a month after administration of antituberculosis agents. However, a mass shadow in the right upper lobe was found 3 months later. Bronchofiberscopy revealed a polyp with a stalk at the orifice of right upper bronchus, which was elastic, soft in consistency, smooth surfaced, and movable. The pathological findings of the polyp showed non-specific inflammatory granu lation which suggested to be inflammatory bronchial polyp. It was appeared in the healing process of bronchial tuberculosis.

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As far as short course chemotherapy of pulmonary tuberculosis is concerned, Japan is considered to have been a little behind the trend of the world in the past. However, since 1978 the concept of the chemotherapy has begun to be adopted in some hospitals and research councils (Cooperative Study Unit of Chemotherapy of Tuberculosis of National Sanatoria, Tuberculosis Research Committees, Ryoken), and then seems to be prevailing in other hospitals as the results of their gradual understanding. This movement has likely been accelerated since Dr. W. Fox came to Japan in 1978 at the invitation of Japanese Society of Tuberculosis and gave us much information and suggestion through his special lecture on short course chemotherapy of tuberculosis.
Fifteen years have pasted since short course chemotherapy started in Japan. At this opportunity, I would like to review the results of short course chemotherapy studies reported by Japanese investigators.
Bacteriological relapse rates in cases followed-up for three years and for from five to nine years after the end of short course chemotherapy were 1.9% (20 out of 1067) and 3.3% (26 out of 783), respectively.
According to the analysis of the time of relapse after completion chemotherapy, bacteriological relapses could be divided into two types. One was early relapse which occurred within one year after completing treatment, and the other was late relapse which occurred two or three years after completing treatment.
It is very difficult to analyze clinically the factors related to relapses after treatment because the amount of bacilli at the start of treatment, speed of negative conversion, existence of cavity and the character of cavitary wall had no influence on relapse of pulmonary tuberculosis.
Although it is not clear what factors were responsible for relapses after the completion of chemotherapy, further preferable research for short course chemotherapy and important counterplan in relation to prevention from occurring relapse tuberculosis were mentioned.

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According to the operational definition adopted at Wolfheze Workshop held in March 1991 (Table 1), tuberculosis low incidence countries are defined as those where the incidence of all forms of tuberculosis is less than 1 per 100, 000. The incidence was 41.9 in 1990 in Japan, so that Japan cannot be considered as a low incidence country. Why is the incidence of tuberculosis so high in Japan? What part of population is affected by the tuberculosis disease? To solve these questions and to make clear the mode of development of tuberculosis, a study was carried out.
Fortunately, both the annual risk of tuberculosis infection and the prevalences of persons with healed and/or fibrotic lesion in the lung are known from the results of the National Tuberculosis Prevalence Surveys carried out in 1963 and 1973 as shown in Figures 1 and 2. From these data, the number of newly infected within 5 years and that of remote infections by age group were estimated. The former was divided into BCG vaccinated and non-vaccinated and the latter into persons with fibrotic lesion, with healed foci and without abnormality in the lung. (Table 2)
The rates of development of tuberculosis disease according to the X-ray findings of the lung were observed at the five-years follow-up study of all the examinees at the Prevalence Survey carried out in 1968. The ratio of development of the disease in those with recent infections, remote infections with fibrotic lesion, those with healed foci and those without abnormality was estimated as 20: 10: 2: 1. (Table 3) As the risks of development of the disease vary with age, so that the parameters shown in Table 4 were used for the estimation of the number of new cases.
The results of estimation of the number of new cases by age group in each calendar year are shown in Fig. 3 and Table 5. The fitness of the estimation was fairly good except that of 1975. The author discussed the reasons of under-estimation of new cases among 20-39 years of age in 1990 and those among 40 years of age or more in the text, although it is omitted here. It was estimated that 91.6% of new cases were developed from the persons with remote infection, and only 8.4% of them were developed from those infected during the last 5 years. The patients with disease reactivated from fibrotic lesion occupied 11.4% and those with healed foci 16.4% according to the estimation done in 1990.
The estimation of the number of new cases that will be developed in 2000 was done by the same method. Total number of new cases was estimated as 35, 049 or 26.7 per 100, 000. The results of the calculation showed that 97.7% of new cases are to develope from the persons with remote infection. (Table 7) Although the persons infected within 5 years would be 0.03% of the total population, 3.2% of the patients would occur from them. (Table 8) It was clearly shown that the persons with fibrotic lesion are one of the highest risk groups of tuberculosis. It is not difficult to detect the persons with fibrotic lesion in Japan where Xray examinations are very common, therefore, preventive chemotherapy for those persons has been recommended.
From the results of the estimation of tuberculosis in 2000, the author concluded that active implementation of several tuberculosis control measures as shown in Table 9 would be advised to accelerate the elimination of tuberculosis in Japan. The prevalence of HIV infection is not so high at present, however, it is increasing rapidly as shown in Fig. 5. The author stressed the importance to decrease tuberculosis before the spread of HIV infection in Japan.

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