Control of cattle TB in Japan

Traditional food custom of Japan changed after the opening of the country in late 19th century, and habit of eating beef and of drinking milk was introduced, and the control of cattle TB had become one of major topics of veterinary medicine in Japan. Old tuberculin (OT) prepared by Koch R in 1890 initially intended to cure TB, however, it was found ineffective against TB, while local and general reactions after the introduction of OT were found to be useful to detect TB infection, and OT was first applied in veterinary medicine to detect TB infection in cattle. Cattle TB Control Law was legislated in Japan in 1901, and cattle was subjected to health checking including tuberculin test, and TB cattle had to be slaughtered, and TB suspects had to be isolated. Several trials had been done to improve the implementation of the Law by increasing the number of experts in health checking of cattle including tuberculin test and compensation for cattle slaughtered during isolation, and they were partly achieved in the revision of the Law in 1933. However, no marked progress was achieved up to 1945 because of war conditions. In 1948 during the occupation period by the US, tuberculin test method was changed to intradermal skin test method by the strong recommendation of the GHQ, and some lawsuits were raised to slaughter cattle based on tuberculin positive reaction by the newly introduced intradermal method. Autopsy was done for slaughtered cattle due to tuberculin positive test results, and as shown in Table 1, TB lesions were found in the majority of autopsied cattle, and thereafter, no more lawsuits were raised. Annual examination including tuberculin test has been continued hard thereafter, and as shown in Fig. 3, the prevalence of TB cattle has dropped down rapidly, and only one or few TB cattle were found by the annual examination, and TB has been nearly eliminated from cattle in Japan. The efforts made by those engaged in the fight against TB in cattle in Japan were highly appreciated.