Abstract #M49
Section: Animal Health
Session: Animal Health: Immunology
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
Session: Animal Health: Immunology
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
# M49
Comparison of antibody response, bacteriological culture and PCR based diagnostic methods in Brucella ovis inoculated rams.
Ariel O. Miranda*1, Hernán Romero Harry1, Valeria N. Baldone1, Marcy Owens2, Scott Pratt2, 1INTA, Anguil, La Pampa, Argentina, 2Clemson University, Clemson, SC.
Key Words: Brucella ovis, diagnostic tools, PCR diagnostic
Comparison of antibody response, bacteriological culture and PCR based diagnostic methods in Brucella ovis inoculated rams.
Ariel O. Miranda*1, Hernán Romero Harry1, Valeria N. Baldone1, Marcy Owens2, Scott Pratt2, 1INTA, Anguil, La Pampa, Argentina, 2Clemson University, Clemson, SC.
Twenty-seven Brucella ovis (B. ovis)-negative adult Pampinta rams were used to evaluate 3 diagnostic methods for B. ovis detection post-inoculation. Twenty-four rams were inoculated by the conjunctival route and intraprepucially with a total of 3 × 109 cfu/ram of B. ovis (strain, INTA Bariloche, Argentina). Three rams were inoculated with a saline placebo. Blood and semen samples were taken for serological antibody detection, bacteriology culture and PCR at 0, 12, 24, 62 and 97 d post inoculation. Modified Thayer Martin medium was used to detect presence of B. ovis in semen. Serum samples were tested for antibodies to B. ovis using a commercial ELISA kit. B. ovis DNA from semen samples was extracted using a commercial kit (Qiagen) and PCR performed using primers pairs specific to B. ovis. The proportion of agreement (Kappa value, κ) was calculated. B. ovis was not detected 12 d post-inoculation by any detection method. Nine rams were positive for B. ovis 24 d post-inoculation detected by ELISA; however, the rams were negative for B. ovis using the other 2 detection methods. Further, we observed a continued increase toward the end of the study. The intermittent elimination of B. ovis by semen agrees with the lower result response in culture and PCR. The low percentage of positive animals in culture on the 97 d could have been given to false negatives or methodology. Control group was negative to the 3 methods over the study. Seroconversion confirmed by ELISA is the most sensitive diagnostic measure of B. ovis exposure.
Table 1. Number and percentage of positive rams by different methods and κ value between them throughout the study
| Test diagnostic | Sampling day | ||||
| 0 | 12 | 24 | 62 | 97 | |
| ELISA positive | 0 | 0 | 9 (38%) | 21 (88%) | 23 (96%) |
| Culture positive | 0 | 0 | 0 | 14 (58%) | 2 (8%) |
| PCR positive | 0 | 0 | 0 | 18 (75%) | 17 (71%) |
| Agreement (%), κ-value (SE) | |||||
| ELISA vs. culture | 100, 1.0 (–) | 100, 1.0 (–) | 62, 0.11 (0.10) | 70, 0.33 (0.16) | 12, 0.00 (0.01) |
| ELISA vs. PCR | 100, 1.0 (–) | 100, 1.0 (–) | 62, 0.11 (0.10) | 70, 0.07 (0.20) | 75, 0.19 (0.17) |
| Culture vs. PCR | 100, 1.0 (–) | 100, 1.0 (–) | 100, 1.0 (–) | 83, 0.63 (0.15) | 37, 0.07 (0.05) |
Key Words: Brucella ovis, diagnostic tools, PCR diagnostic
