Diagnosis of Brucella abortus and Brucella melitensis in the Milk of Cattle and Sheep in Kordestan Province by Polymerase Chain Reaction

Brucellosis is an important zoonotic disease in humans and animals. Brucellosis has been reported from most countries، but in some countries including Iran the disease is endemic. Consumption of milk and products of infected animals is a major transmission source of infection to humans. Since in most provinces of Iran such as Kurdestan province، cattle and sheep are kept close together، it is possible that animals are infected with non-specific Brucella species. The aim of this study was to use PCR in detection of Brucella species in milk، and also to detect the host specificity of Brucella abortus and Brucella melitensis in cattle and sheep. In this research، 60 milk samples from suspected cattle and 50 milk samples from suspected sheep in different villages of Kurdestan province were collected. DNA was extracted from all milk samples directly. In order to detect the Brucella spp. PCR was carried out using B4 and B5 primers on all extracted DNAs and in order to detect the B. abortus and B. melitensis، PCR was carried out with B. a، B. m and IS711 primers on all DNAs. Using PCR for detection of Brucella spp. 20 and 22 of milk samples were positive in cattle and sheep samples respectively. Using PCR، out of the 20 cattle positive samples، 9 samples were identified as B. abortus (biovar 1، 2 and 4)، and 2 samples were identified as B. melitensis. Also out of the 22 sheep positive samples، 15 samples were identified as B. melitensis and 1 as B. abortus (biovar 1، 2 and 4). Regarding the fact that in two milk samples of cattle، B. melitensis and in 1 milk sample of sheep، B. abortus were detected، the animals that were kept in close contact with each other may lose the host -specificity. Based on the results of this research، it is recommended that in order to detect Brucella spp. in milk samples. The vaccination status should be detected and using specific primers for detection of all biovars of Brucella abortus and Brucella melitensis، PCR and cultural methods should be carry out.