TABLE 1

Tuberculin skin test and pathology results obtained from M. bovis-inoculated cattlea

Animal IDbSCT resultc (mm)CCT resultd (mm)Gross lesion scoree
Lymph nodesfLungsg
813.58.020
5143.229.535
5329.128.035
542451.533
552319.534
5636.738.035
5711.97.034
  • a Mycobacterium bovis was isolated from a pool of thoracic lymph nodes following procedures used for clinical samples at the National Veterinary Services Laboratory, Ames, IA. M. bovis was identified in all cultures.

  • b ID, identification number.

  • c SCT was administered at week 13 postinoculation; results are shown as the change in skin thickness 72 h after bovine PPD injection.

  • d CCT was administered at week 30 postinoculation; results are shown as the difference between reactions to bovine PPD and to avian PPD measured 72 h after bovine PPD injection.

  • e Gross lesion scoring system was used as described by Vordermeier et al. (25).

  • f Tracheobronchial and mediastinal lymph nodes were examined for gross pathology using the following scoring scale: 0, no necrosis or visible lesions; 1, one small focus (1 to 2 mm in diameter); 2, several small foci; 3, extensive necrosis.

  • g Lungs were examined for gross pathology using the following scoring scale: 0, no visible lesions; 1, no external gross pathology but lesions seen upon slicing; 2, <5 visible lesions of <10 mm in diameter; 3, ≥5 visible lesions of <10 mm in diameter; 4, >1 distinct visible lesion of >10 mm in diameter; 5, gross coalescing lesions. All animals except animal 8 had visible lesions in all lobes.