TABLE 2.
Sensitivities and specificities of tests using polysaccharide or S-LPS antigens for the serological diagnosis of bovine brucellosis in the presence of interferences due to Y. enterocolitica O:9a
| Test | Antigen | % Sensitivity (95% CI) and no. of sera tested for cattle infected with:
|
Cutoffb | % Specificity (95% CI) and no. of sera for Brucella-free cattle:
|
||||
|---|---|---|---|---|---|---|---|---|
| B. abortus | B. melitensis | Either brucella | Not exposed to Y. enterocolitica O:9 | Experimentally infected with Y. enterocolitica O:9 | From FPSR herds | |||
| RBT | B. abortus whole cells | 100 (97.1-100), 114 | 100 (95.7-100), 75 | 100 (98.2-100), 189 | 100 (96.7-100), 112 | Not applicable | 86.4 (79.1-91.9), 125 | |
| CFT | B. abortus whole cells | 100 (97.1-100), 114 | 100 (95.7-100), 75 | 100 (98.2-100), 189 | 20 | 100 (96.7-100), 112 | Not applicable | 94.4 (88.8-97.7), 125 |
| Indirect ELISA | B. melitensis crude S-LPS | 100 (96.8-100), 114 | 100 (95.2-100), 75 | 100 (98-100), 189 | >31.12 | 100 (96.7-100), 112 | 42.9 (24.5-62.8), 28 | 58.4 (49.2-67.1), 125 |
| B. melitensis NH | 100 (96.8-100), 114 | 100 (95.2-100), 75 | 100 (98-100), 189 | >35.29 | 100 (96.7-100), 112 | 42.9 (24.5-62.8), 28 | 94.4 (88.8-97.7), 125 | |
| B. abortus PS | 100 (96.8-100), 114 | 100 (95.2-100), 75 | 100 (98-100), 189 | >23.07 | 100 (96.7-100), 112 | 7.1 (1.1-23.5), 28 | 36.8 (28.4-45.9), 125 | |
| B. suis S-LPS | 100 (96.8-100), 114 | 100 (95.2-100), 75 | 100 (98-100), 189 | >15.87 | 100 (96.7-100), 112 | 0 (0.0-12.5), 28 | 20 (13.4-28.1), 125 | |
| E. hermanni S-LPS | 95.3 (84.2-99.3), 43 | 100 (91.7-100), 43 | 97.7 (91.8-99.7), 86 | >75.04 | 100 (91.3-100), 41 | 100 (80.3-100), 17 | 29.6 (13.8-50.2), 125 | |
| Chaotropic ELISA | ||||||||
| 1 M KSCN | B. melitensis crude S-LPS | 100 (96.8-100), 114 | 100 (95.2-100), 75 | 100 (98-100), 189 | >12.62 | 100 (96.7-100), 112 | 64.3 (44.1-81.3), 28 | 84 (76.4-89.9), 125 |
| 2 M KSCN | B. melitensis crude S-LPS | 97.4 (92.5-99.4), 114 | 98.7 (92.8-99.8), 75 | 97.9 (94.7-99.4), 189 | >25.79 | 100 (96.7-100), 112 | 100 (87.5-100), 28 | 97.6 (93.1-99.5), 125 |
| 3 M KSCN | B. melitensis crude S-LPS | 89.5 (82.3-94.4), 114 | 88 (78.4-94.4), 75 | 88.9 (83.5-93), 189 | >21.22 | 100 (96.7-100), 112 | 100 (87.5-100), 28 | 100 (97.1-100), 125 |
| Competitive ELISA | B. abortus S-LPS | 90.5 (83.2-95.3), 105 | 76 (64.7-85.1), 75 | 84.4 (78.3-89.4), 180 | >35.73 | 100 (95.9-100), 90 | 85.7 (67.3-95.9), 28 | 88.8 (81.9-93.7), 125 |
| Double gel diffusion | B. melitensis crude S-LPS | 85.1 (77.2-91.1), 114 | 93.3 (85.1-97.8), 75 | 88.4 (82.9-92.6), 189 | 100 (96.7-100), 112 | 100 (87.5-100), 28 | 100 (97.1-100), 125 | |
| NH-RID | B. melitensis NH | 92.9 (85.1-97.3), 84 | 94.2 (85.8-98.4), 69 | 93.5 (88.3-96.8), 153 | 100 (96.7-100), 112 | 100 (87.5-100), 28 | 100 (97.1-100), 125 | |
a
Cutoffs for ELISAs were selected to result in 100% specificity with the sera from Brucella-free animals not exposed to Y. enterocolitica O:9.
b
See Materials and Methods for the definition of the cutoff for each test.