Shedding Rates and SeroPrevalence of Brucella melitensis in Lactating Goats of Shahrekord, Iran

BACKGROUND: Brucellosis remains a major worldwide zoonosis. Caprine brucellosis is a significant problem for both public health and animal production. Brucella melitensis causes disease in goats, sheep, humans, and occasionally cattle. Transmission is by ingestion or contact with infected materials, vaginal discharge, or milk. OBJECTIVES: The current study aimed to determine the rate of B. melitensis seropositives and its probable shedding in lactating goats from flocks in Shahrekord district, Iran. MATERIALS AND METHODS: In the current study, 1080 samples of milk, blood and vaginal swabs of 360 lactating goats (three samples from each animal) were randomly collected from 12 flocks in Shahrekord district. Serums from blood samples were examined by Rose Bengal plate (RBT) test and the titre of positives determined by tube agglutination test (TAT). Vaginal swab and milk (cream and sediment) samples were cultured on Brucella agar. Brucella spp. suspected pure cultures were incubated in the same conditions and then examined by Modified Zeil-Nelson (MZN) staining, oxidase and catalase tests. Positive isolates were examined by PCR. RESULTS: Out of 360 serum samples, 50 (13.9%) were positive by RBT, and six (1/66%) were positive by TAT. Culturing of milk and vaginal samples lead to isolation of 12 (3.33%) and 10 (2.77%) Brucella spp. suspected colonies, respectively. The PCR examinations of these isolates showed that ten (2.77%) milk and 6 vaginal swab samples (1.66%) belonged to B. melitensis species. Eight goats (2.22%) had positive results in RBT, culture and PCR examinations, simultaneously. CONCLUSIONS: The regional distribution of caprine brucellosis and shedding of B. melitensis through vaginal secretions and milk secretions of lactating goats indicated that 50% and 83.33% of the goat flocks contained vaginal and milk shedders, respectively.