Overall serological responses of sera from naturally or experimentally M. bovis- or M. avium subsp. paratuberculosis-infected or -free cattle or deer in an EIA, an ICGA, or an LBAA utilizing rMPB70 or ESAT6-p as the coating or conjugating antigena

Antigen and assayNo. of positive sera/no. testedd
M. bovis-infected animalsaM. bovis-free animalsb
CattleDeerTotalM. avium subsp. paratuberculosis freeM. avium subsp. paratuberculosis infectedTotal
Naturally infectedcExperimentally inoculatedTotal
    EIA272/300 (90.7)17/20 (85.0)289/320 (90.3)4/4 (100)293/324 (96.8)5/155 (96.8)1/157 (99.4)6/312 (90.1)
    ICGA248/300 (82.7)18/20 (90.0)266/320 (83.1)3/4 (75.0)269/324 (83.0)2/155 (98.7)0/157 (100)2/312 (99.4)
    LBAA259/300 (86.3)18/20 (90.0)277/320 (86.6)4/4 (100)281/324 (86.7)5/155 (96.8)2/157 (98.7)7/312 (97.8)
    EIA300/300 (100)16/20 (80.0)316/320 (98.8)4/4 (100)320/324 (98.6)4/155 (97.4)4/155 (97.4)4/312 (98.5)
    LBAA283/300 (94.3)20/20 (100)303/320 (94.7)4/4 (100)307/324 (94.8)15/155 (90.3)15/155 (90.3)23/312 (92.6)
  • a The group of M. bovis-infected animals (n = 324) included cattle (n = 320) (both naturally infected cows [n = 300] and experimentally inoculated calves [n = 20] and experimentally inoculated deer (n = 4). Values in parentheses are sensitivities (given as percentages).

  • b The group of M. bovis-free animals (n = 312) included both M. avium subsp. paratuberculosis-free animals (n = 155) and M. avium subsp. paratuberculosis-infected cattle (n = 157). Values in parentheses are specificities (given as percentages).

  • c Natural M. bovis infection was checked by the SID test (over 5-mm skin thickness after the test) and culture of M. bovis from intestinal tissue or nasal and tracheal mucus at the time of necropsy.

  • d Detailed information on how natural M. bovis or M. avium subsp. paratuberculosis infection was confirmed, how M. bovis or M. avium subsp. paratuberculosis was inoculated experimentally, and how a positive response in the EIA, LBAA, or ICGA was defined is given in Materials and Methods. Although one M. bovis-inoculated calf with NVL and three deer at the NVL stage (90 days p.i.) were negative by M. bovis culture, their sera showed a positive response with ESAT6-p by the EIA and LBAA, and serum from one NVL calf also reacted positively with rMPB70 by the LBAA. The specificity of the EIA with ESAT6-p or rMPB70 was also affected because the specificity of the EIA was calculated by comparing the result of bacterial culture or a skin test with that of the EIA by ROC analysis with the Analyse-it program. The EIA and the ICGA kit using rMPB70 were obtained from Animal Genetics Inc. (Suwon, South Korea), and the other assays (the EIA with ESAT6-p and the LBAA) were developed in this study.