Molecular detection of Brucella spp in goat and sheep milk samples from apparently healthy and infected animals

Brucellosis is a worldwide spread zoonotic disease caused by some strains of Brucella spp. which is a bacterium simply transmitted to human among domesticated animals. PCR assay is authentic, inexpensive, sensitive, and highly specific for Brucella DNA detection in milk samples. This study set to assess the PCR assay for the molecular recognition of Brucella DNA in goats and sheep unpasteurized milk samples in the southeast region of Iran and to determine the frequency distribution of seasonal outbreaks. Eight hundred samples of raw milk from 722 apparently healthy animals and 78 infected animals with a history of abortion were collected from January 2015 to June 2016. In our PCR, a specific genome region, the IS711 element, was targeted to amplify Brucella DNA, and the frequency distribution of seasonal outbreaks was determined. PCR assay amplified Brucella DNA in 10.85% goats and 5.45% sheep milk samples (CI = 95). Among samples with abortion history, the disease occurrence rate was 67.94% but among those without abortion history, it was 2.21%. The most frequent rates of brucellosis were seen in the summer (n = 33), and the lowest rate occurred in the winter (n = 3). The results indicated a significantly higher prevalence (p < 0.05) of disease in samples with abortion history, and the results also indicated that the goats had a higher prevalence of brucellosis as in comparison with sheep. There was a significant statistical difference between the seasons.