実験的豚結核病におけるツベルクリン反応

Abstract

Studies on tuberculous pigs in Japan by some authors made it clear that the isolates from them, were usually human type tubercle bacilli (HTB). This finding is different from the high incidence of avian type tubercle bacilli (ATB) among tuberculous pigs in Europe and America.The present studies consisted of intradermal tuberculin testing and pathological examination of young piglets experimentally infected with two strains of HTB, one strain of bovine type (BTB), and two strains of ATB. The two strains of ATB were proved to be virulent causing fatal tuberculous infection in chickens. Heat-concentrated synthetic-medium tuberculin was prepared from culture of HTB and BTB or of ATB. The potency of avian tuberculin was proved to be satisfactory when examined on chickens infected with ATB. Both types of tuberclin were used at twofold dilution in the tuberculin testing of piglets. The increase of thickness at the injected site was read at the 24th, 48th, and 72nd hour.A reaction higher to mammalian tuberculin than to avian tuberculin was usually observed in tuberculin testing on piglets infected with HTB or BTB. Contrary to this finding, a reverse relationship in tuberculin testing was observed in piglets infected with ATB. From these results, the type of the causal agent in a tuberculous piglet could be identified from the results of a comparative method in accordance with many other authors findings.In piglets infected with virulent BTB, generali zed tuberculosis was observed involving lung, liver, spleen, and their neighboring lymph nodes. Usually tuberculos lesions were limited to the inoculated site and its neighboring lymph nodes in piglets infected with ATB. The distribution of tuberculous lesions was observed to be more slight in piglets infected wih HTB than in those infected with BTB. The pathogenicity of the strains of HTB used in this experiment was rather attenuated.