Pathogenicity for cattle of atypical mycobacteria isolated from feral pigs and cattle and the correlation of lesions with tuberculin sensitivity.
Two experiments involving the inoculation of cattle with atypical mycobacteria are described. In the first experiment groups of 5 cattle were inoculated either subcutaneously or into a mesenteric lymph node with a strain of M. scrofulaceum or M. intracellulare. Four weeks and 10 weeks after inoculation the cattle were tuberculin tested with bovine PPD, avian PPD and homologous PPDs. The pathological changes observed were similar within each group of cattle inoculated with the same strain of mycobacteria. A significant interaction was demonstrated between the strain and the route of inoculation. In the second experiment 17 cattle were similarly inoculated by either of the two routes with 1 of 6 strains of M. intracellulare, a strain of M. scrofulaceum or a strain of Runyon Group IV, all of which had been isolated from feral pigs, or a strain of M. intracellulare of bovine origin. Tuberculin tests were carried out after 4 weeks and 10 weeks. Only the isolate from a bovine lymph node produced a significant level of sensitivity to bovine PPD. Cultural isolation of the mycobacteria from autopsy material was not correlated with the presence of macroscopic lesions nor with sensitivity to bovine PPD. The response to bovine PPD of cattle infected with these atypical mycobacteria decreased between 48 h and 96 h after injection of the tuberculins. As the maximum difference in the response to bovine and avian tuberculins occurs at 72 h a comparative tuberculin test should be read at this time to eliminate non-specific reactors.
D000818:Animals; D002417:Cattle / Q000382:microbiology; D002418:Cattle Diseases / Q000276:immunology* / Q000473:pathology; D006968:Hypersensitivity, Delayed / Q000276:immunology / Q000662:veterinary*; D008198:Lymph Nodes / Q000473:pathology; D009164:Mycobacterium Infections / Q000662:veterinary*; D009165:Mycobacterium Infections, Nontuberculous / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D009170:Nontuberculous Mycobacteria / Q000302:isolation & purification; D012867:Skin / Q000473:pathology; D013552:Swine / Q000382:microbiology; D014374:Tuberculin Test / Q000662:veterinary*