Tuberculous Pigs Research Articles

An abattoir-based case-control study of risk factors for mycobacteriosis in Norwegian swine

An outbreak of mycobacteriosis in swine herds in southwestern Norway from autumn 1986 to 1990 is described. The prevalence of generalised infection in the pigs was higher than usual during the outbreak resulting in the condemnation of 0.3% of the swine carcasses in 1987. A case-control study involving 35 herds (17 herds with more than two tuberculous pigs at slaughter and 18 herds with no evidence of infection at slaughter) showed that an increased risk of infection was linked to combined production with sows and slaughter pigs in the same herd. The presence of birds in the pig house was another contributing risk factor. The standard of the ventilation system, covering of the feed tank, cleaning of the house less frequently than once a year and use of litter were not associated with tuberculous lesions.

実験的豚結核病におけるツベルクリン反応

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.