Comparison of PCR and Conventional Serological Methods for Detection of Brucella spp. in Ovine and Caprine Blood Serum

Brucellosis is an anthropozoonotic disease. Infection of livestock with Brucella is endemic in most parts of Iran. Sistan-Baluchestan is bordered on the east by the countries of Afghanistan and Pakistan. The high prevalence of brucellosis in livestock in the eastern neighboring countries results in transmission of the disease to this province. The present research aimed to determine the prevalence of brucellosis in small ruminants in the Sistan region of Iran and to compare serological and molecular tests for the detection of brucellosis. Blood samples were taken from 150 randomly selected sheep and goats, and sera were separated. All sera were analyzed by serological (Wright and 2-ME) and molecular (Polymerase Chain Reaction (PCR)) tests. Serological tests were carried out according to the instructions of the Iranian Veterinary Organization The degree of agreement between serological tests and PCR was determined by kappa value. In this study, 17 cases (11.3%) were identified as positive by the PCR method. Wright and 2-ME tests had the highest agreement with PCR in titers ≥2/80 and ≥2/40, respectively. The results of this study show that the brucellosis in sheep and goats has a greater prevalence in the Sistan region than in most other parts of Iran, and this is important in terms of public health. It is suggested that brucellosis vaccination coverage in livestock be increased in this area and that the people in Sistan region must be notified about methods for preventing brucellosis. Also, further studies to compare conventional serologic tests with the gold standard test are recommended.