The comparison of Multiplex PCR with serological method for determination of occurrence of Brucella in Sheep blood

Introduction and Objectives: The genus Brucella consists of 10 species, of which Brucella abortus (B. abortus), and Brucella melitensis (B. melitensis) are pathogenic for cow and sheep. Also, they are the main pathogenic species in human. Developing countries have still problem with brucellosis. Since the clinical feature of the disease is nonspecific; serological tests that were replaced to culture methods but, they have little sensitivity, especially in the early stages of the disease that production rate of the antibody is low. Thus, recently molecular methods have been used to distinguish the pathogen. This study aimed to determine the occurrence rate of Brucella in sheep blood through comparison of serological test and Multiplex-PCR. Materials and Methods: A total of 70 blood samples were taken from 70 individual sheep. Rose Bengal test (RBT), Wright and 2ME were performed on the isolated serum. DNA was extracted from the whole blood. Multiplex-PCR was used for determination of B. abortus and B. melitensis. Result: Overall, 4 (5.7%) of the serum samples were positive according to RBT test, while 9 (9.9%) of the serum samples were positive according to Wright and 2ME tests. Twenty-five (35.7%) blood samples were found positive on PCR-amplified IS711 gene for detection of B. abortus, while none of the samples were positive for B. melitensis gene. The differences of serological test and PCR-IS711 were highly significant (P<0.05). Conclusion: Interestingly, sheep bloods have a high level of contamination with B. abortus. Molecular method is more sensitive than serological tests for detection of Brucella spp.

Keywords:

Brucella , PCR , sheep.