Research Article

Diagnostic Efficiency of Different Serological Tests and Real time PCR for Detecting Brucella Infection in Camels' Sera

Mahmoud E.R. Hamdy, Mahmoud H. Abdel Haleem, Mohamed K. Al-kholi and Soliman S. Hazem
Department of Brucellosis, Animal Health Research Institute, (AHRI) - Dokki, Giza, Egypt.

Abstract

Evaluation of the real-time PCR, rose bengal test (RBT), competitive ELISA, and complement fixation test (CFT) was done on 335 camels sera. Real-time PCR, classified 335 camel serum samples to 268 (80%) as positive and 67 (20%) as negative. Real-time PCR, using species specific primers, distinguished 94/104 serum samples due to B. abortus, 4/104 samples due to B. melitensis and 6/104 due to mixed infection. The results of serological tests revealed that modified mRBT75 using 75 µl of serum, detected the highest number of positive samples 271 (80.9%), while 262 (78.2%), 257 (76.7%), 253 (75.5%) and 245 (73.1%) samples were found to be positive for brucellosis using CFT, cELISA, mRBT50, and RBT25, respectively. Compared to other serological tests, the CFT proved to have the best results in the criteria of test validations, namely; specificity (88%), PPV (96.9%), NPV (80.8%), PLR (7.9), NLR (0.06) and DOR (133.8). The Kappa (K) statistic agreements values between real-time PCR and rose bengal (RBT25), modified (mRBT50), (mRBT75), cELISA and CFT was 0.562 (± 0.053), 0.613 (± 0.052), 0.725 (± 0.048), 0.710 (± 0.047) and 0.801 (± 0.041), respectively. The authors recommend the use of real-time PCR on camel sera to confirm the disease.

Keywords

Brucella, Camels, Real time PCR, Serological Tests, Validation.