Average numbers of tissues positive by culture and histopathology among tissues obtained from calves at necropsy 12 months following oral or intraperitoneal challenge with live Mycobacterium avium subsp. paratuberculosisa

Tissued% Positive tissues for treatment group (unless stated otherwise)
Jejunum + LN (proximal, mid-, and distal)b54254267
Ileum + LN (proximal, mid-, and distal)c17251750
Duodenum + LN50503850
Ileocecal valve501005067
Ileocecal LN2550033
Iliac LN75505033
Spiral colon + LN63253850
Transcending colon + LN13132550
Descending colon + LN2501317
Avg no. of positive tissue sites10.38.59.515
Avg no. of tissues with lesions1983115
  • a The total number of tissue sites sampled per calf was 22.

  • b Three sections of the jejunum (proximal, mid-, and distal sections) plus three associated lymph nodes (n = 6) were sampled.

  • c Three sections of the ileum (proximal, mid-, and distal sections) plus one associated lymph node (n = 4) were sampled.

  • d Tissue + LN, the lymph node (LN) associated with that tissue site was also collected (n = 2 tissue sites).