An epidemiological survey was carried out on the effects of the special tuberculosis control programme conducted during the period from 1969 to 1971 in Nagata-ku, Kobe City.
The coverage of the mass survey for general inhabitants was verly low in the area and it rised up to 50 to 70%, and moreover, an attempt has been made to promote patients to receive treatment regularly by using the “communication memo” between physicians and the health center. Though three years' period might be too short to obtain some effects, the evaluation of the programme was made by analyzing the epidemiological status of newly registered cases and of tuberculosis death.
The results obtained are as follows:
1) As to the role of foreigners in the prevalence of tuberculosis in the area, the proportion of foreigners among newly registered cases and tuberculosis death were 4-5% and less than 7%, respectively.
2) The number of moved-in patients for the sake of receiving treatment was less than 2% among newly registered cases, and less than 6% among tuberculosis death.
3) The number and the rate of newly detected patients to the whole newly registered cases decreased year by year.
4) The number and the rate of families with tuberculosis patients in the same family showed reduction.
5) The number and the rate of cases with previous history of tuberculosis has been increasing.
6) The number and the rate of cases newly detected by the mass survey has been increasing.
7) The number and the rate of active infectious cases at the time of registration to cases with previous history of tuberculosis increased year by year.
8) The number and the rate of tuberculosis death remained on the same level.
9) The number of those who were registered and died of tuberculosis in Nagata-ku in creased slightly.
10) Of tuberculosis deaths, 57 to 68% were active infectious at the time of registration.
11) The duration of disease from registration to tuberculosis death was 4.0±3.2, 5.2±3.6 and 4.0±3.7 years, respectively, in 1968, 1969 and 1970.
12) The number of tuberculosis death which were not registered previously was 22, 13 and 14, respectively, in 1968, 1969 and 1970.
The above mentioned findings are summarized as follows: a) many previously unknown patients were detected in accordance with the expansion of the mass survey, b) the detection rate of new cases by the mass survey was first rather high, and it reduced gradually, c) no decrease was seen in the number of tuberculosis death during this period.
Comparing the incidence rate of newly registered cases and the prevalence of active tuberculosis in Nagata-ku, Kobe City and the whole country, the incidence rate in Nagata-ku and that in the whole country decreased faster than the rate in Kobe City: while the prevalence of active tuberculosis in Nagata-ku and that in Kobe City fell more rapidly than that in the whole country.
In conclusion, the special tuberculosis control programme of 3 years' period consisting mainly of the mass survey for general inhabitants and workers in smaller enterprises and the supervision of detected cases gave some effects on the incidence rate and the prevalence of tuberculosis while it gave no influence on tuberculosis mortality.

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A follow-up survey of tuberculin reaction was carried out in the autumn of 1969, one year after the first Survey, on children in Okinawa, aged 0 to 13 or 14 years (2nd grade of junior high school), who had been perfectly examined at the Tuberculosis Prevalence Survey in 1968.
Tuberculin tests were performed on 8, 499 children with attendance rate of 99.5%, and the children whose transverse diameter of induration was 5mm or more, were examined by chest radiograms.
On 7, 337 children who had never been vaccinated with B.C.G., changes in the results of tuberculin reaction from 1968 to 1969 were analyzed in relation to several factors such as sex, age, the presence or absence of tuberculous patients in their households, etc.
Moreover, the background factors of newly detected TB suspects were studied, and the prevalence of healed lesions on chest radiograms was observed by the degree of tuberculin allergy.
The results were as follows:
1) The positive conversion rate by age was 1.16% for 0-4 years, 0.79% for 5-9 years, 3.57% for 10-14 years and 1.67% for the total. Among children with tuberculous patients in their households, the positive conversion rate was 5.5 times higher than that of children without patients.
2) The negative conversion rate by age was 22.86% for 0-4 years, 26.98% for 5-9 years, 18.40% for 10-14 years and 21.16% for the total. Children who were strongly positive in 1968 or who had tuberculous patients in their households, showed lower negative conversion rate.
3) Seven new TB suspects were detected by chest radiograms and five of them were primary tuberculosis with hilar lymphnode swelling. Among them, three were the family member of active-infectious TB patients.
4) Prevalence of healed lesions on chest radiograms increased proportionally to the intensity of tuberculin allergy.
The positive conversion rate derived from this survey might be somewhat over-estimate of the infection rate among children in Okinawa, as the negative conversion from the positive reactors without previous BCG vaccination was relatively high.
In order to estimate a more reasonable infection rate, it seems to be necessary to develop some new methods considering both negative conversion as well as positive conversion.
These problems will be discussed in the next report.

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To decide the clinical significance of the critical drug resistance concentration, studies were done from two aspects. One was an approach from the distribution of naturally resistant variant of the wild strains and another was the one from the clinical view point. The technique used was the proportion method of Canetti, using 1% Ogawa medium with cork stop.
Proportion of resistant variants to SM, INH and PAS was measured on strains isolated from previously untreated patients. Considering the variation of the proportion between cases in each drug concentration the, variation of the same strain measured at different days or lots (Table 1), and the decreasing trend of the median value of colonies shown in Fig., it seemed reasonable to take 4mcg of SM, 0.1mcg of INH and O.5mcg of PAS as critical concentrations.
For clinical investigation, the grade of drug resistance was divided into 4 categories; that is, sensitive, criteria 1, 2 and 3 as presented in Table 2.
A study was done on cases treated for more than 6 months with 3 major primary drugs and have only one drug resistance of each criteria. Minimal cases were excluded from this study as all of them converted to negative regardless of resistance (Table 3).
According to this study, the treatment failure was found in 0.4% of the sensitive, and 8.3% in criteria 3 among the original treatment group but there was no statistically significant difference, while among the retreatment group, significant difference was found between sensi tive and criteria 2 (Table 6). Accordingly, it seemed to be reasonable to take criteria 2 as a critical concentration from clinical stand points.
Concerning bacillary relapse, temporally or permanent (Table 7), there was a significant difference between sensitive and criteria 3 of the original treatment group and between sensitive and criteria 1 of the retreatment group.
The relation between the period of chemotherapy and resistance was examined from the previous history taken at the time of hospitalization. The number of drug resistant cases according to criteria 3 was too few in number among cases after one year or more treatment with SM, INH and PAS, alone or combinated and resulted in failure (Table 8). Similarily, many of hospitalized cases did not become resistant according to criteria 3 in spite of unsuc cessful treatment (Table 9).
Considering all these facts, we concluded that the clinically significant critical drug resist ance concentration by using 1% Ogawa medium with cork stop is one percent or more of the following drug concentration ; 10mcg of SM, 0.2mcg of INH, and 1mcg of PAS. But it is also recommendable to take 4mcg of SM, 0.1mcg of INH and 0.5mcg of PAS as subcritical concentrations.

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Out of 11, 431 sputum culture conducted during the six years' period from 1966 to 1971, 2, 185 strains of acid fast bacilli have been isolated from the sputums of 574 cases, including 382 strains of atypical mycobacteria from 74 cases.
According to the classification by Runyon, these 382 strains of atypical mycobacteria were classified as follows: 31 photochromogens from 3 cases, 16 scotochromogens from 12 cases, 330 nonphotochromogens from 56 cases and 5 rapid growers from 3 cases.
The isolation rate of atypical mycobacteria in sputum was 3.3 per cent on the average, ranging from 1.6 to 4.5% by year.
No seasonal flactuation was observed for isolation of atypical mycobacteria.
Dividing the number of cultured colonies of atypical mycobacteria into six categories, group (+) showing about 100 colonies turned out to be the largest in number and solitary colony was the smallest.
As regards the relationship between the frequency of discharge and the number of colonies, most of cases discharging atypical mycobacteria once to three times were seen in groups with 1 colony to +, whereas all cases discharging atypical mycobacteria ten times or more were found in groups with colony growth ++ and +++.
As for the frequency of discharge of atypical mycobacteria, 21 out of 74 cases showed discharge of over four times and the remaining 53 cases once to three times.
Among these 53 cases, 12 discharged tubercle bacilli together with atypical mycobacteria.
Out of 74 cases discharging atypical mycobacteria, 48 cases, were male and 26 were female, and the number of cases increased with the age.

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