Current epidemiological trend of tuberculosis among foreigners in Japan

In Japan, the proportion of foreign patients among the total tuberculosis patients is still very small, but their problems in tuberculosis case finding and treatment require intensive control activities as in other low prevalence countries with higher proportion of foreign-born cases. The latest national survey for the foreign tuberculosis patients conducted in 1996 shows the epidemiological status between 1990 and 1993. The number of foreign tuberculosis patients in 1993 was 484, consisting of 1.0% of the total new patients in Japan. The new case rate among foreigners was estimated to be 53 per 100,000 against 38 for whole Japan in 1993. Compared with the figure in the 1993 survey, the number of foreign patients declined from 585 in 1992 to 484 in 1993. However, the number of bacillary positive tuberculosis patients in 1992 was 230 and almost the same as in 1992. The decline or stagnation of total number of tuberculosis patients can be due either to the decrease in the foreign population inflow into Japan (real decline), or partially to the reduction of overdiagnosis in X ray examination and the possible loss of some cases in the 1996 survey method. A manual sorting method from the registration cards was used at each public health center, since there is no item of country of origin in the routine tuberculosis surveillance system, and some cards might have already been displaced by the time of the survey for patients who were excluded from the registry, either cured, died or defaulted. The average treatment completion rate (1991-93) among foreign patients was 51%, which was much lower than the national figure of 81% for the same years. Moreover the rate showed deteriorating trend by year. For more accurate information, the foreigner's data must be taken in the national tuberculosis surveillance system and control activities for foreigners need to be strengthened.