Identification of main Brucella species implicated in ovine and caprine abortion cases by molecular and classical methods

Document Type: Original Articles


Brucellosis Department, Razi Vaccine and Serum Research Institute (RVSRI); Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran


Brucellosis is known as a significant public health concern leading to critical economic losses in livestock animals. In this study, Brucella spp. isolated from aborted ovine and caprine fetuses from 2016 to 2019 in different parts of Iran were investigated with classic and molecular methods in order to determine the Brucella species carrying higher risks of abortion complications in these animals. A total of 189 samples from 35 cases/case series from milk (16 sheep, and 8 goats), 19 abomasum content (sheep), and 146 aborted fetuses (116 sheep, and 30 goats) were examined bacteriologically and the resulting Brucella isolates were further characterized by phenotypic and molecular approaches. The multiplex PCR (Bruce-ladder) and IS711-based polymerase chain reaction was performed on all extracted DNA to evaluate the presence of Brucella spp. According to our results, all recovered isolates from ovine and caprine abortion samples were either B. melitensis or B. abortus. An issue of concern was the implication of the B. melitensis vaccine strain Rev1 in a small portion of sheep and goat abortion cases. In spite of the recent B. abortus burden in ovine, aborted cases were predominantly associated with B. melitensis infections in both ovine and caprine, B. melitensis biovar 1 being responsible for the majority of studied cases. These data, and the techniques implemented in this study, would help to draw a comprehensive picture of the level of implication of different Brucella species in ovine and caprine abortion in Iran. By identifying Brucella agents causing abortion in small ruminants at the biovar level, this work provides precious information for future control program and vaccination strategies in Middle Eastern regions.