Comparison of serology, culture, and PCR for detection of brucellosis in slaughtered camels in Iran

Brucellosis is a zoonotic disease which is characterized by abortion and reduced fertility in many species. Camel brucellosis is caused by Brucella abortus and Brucella melitensis. To investigate sensitive methods in the detection of camel brucellosis, PCR was used to overcome the limitations of serology and culture methods. Three hundred ten camels were examined for brucellosis infection using serological tests (RBPT, mRB, Wright, and 2-ME). In addition, 100 serological tested cases (39 mRB positive and 61 mRB negative) were analyzed with both bacteriological (lymph node culture on Brucella agar supplemented with antibiotics) and PCR (nested-PCR on sera and blood samples) methods. The nested-PCR was genus-specific and amplified the 16S rDNA locus. Six out of 310 (1.94 %) of the examined camels were positive using the serological tests, whereas, no bacteria was isolated from lymph tissues. Nested-PCR was positive in six and nine individuals in sera and blood samples, respectively. The genus-specific nested-PCR assay on blood samples detected a higher number of camel brucellosis compared with serological and classical culture methods. These results have identified a sensitive PCR method which could be used as a complement test for the detection of brucellosis in live camels with the lowest risk of infection to laboratory workers.