Serologic and molecular evidence of Brucella ovis infection in ovine and caprine flocks in the State of Minas Gerais, Brazil

Abstract

Background: Brucella ovis infection is one of the leading causes of sub fertility and infertility in ovine, been characterized mainly by epididymitis, orchitis and testicular atrophy in rams. This study aimed to determine the frequency of B. ovis positivity in rams and goats flocks in the State of Minas Gerais, Brazil, by agarose gel immunodiffusion (AGID), ELISA, Rose Bengal, PCR and bacteriological isolation as diagnostic tools. Findings: Serum and urine samples were collected from properties with sheep or goat flocks, or from properties with mixed flock. Out of 50 sheep flocks, 6 % (3/50) were seropositive by AGID while 4 % (2/50) were positive by urine PCR for B. ovis. Out of five goat farms, 20 % (1/5) were seropositive for B. ovis by AGID. Mixed flock farms had 11.1 % (2/18) of positivity by AGID. By ELISA, 19.5 % (8/41) of sheep properties and 61.1 % (11/18) of the properties with mixed flocks were positive for B. ovis. No samples were positive in the test of Rose Bengal, ruling out exposure to smooth LPS Brucella species (particularly Brucella melitensis) and indicating that the positive in the ELISA was associated with Brucella spp. LPS rough (presumably B. ovis). No urine sample from sheep or goat was positive by bacteriological isolation. Conclusions: Our results demonstrate serologic or molecular evidence of B. ovis infection in several rams and billy goats from meso-regions of the State of Minas Gerais, Brazil. Also, this study report the indirect ELISA as an important tool for the diagnosis of B. ovis infection, as indirect ELISA in this study demonstrated to be the most sensitive diagnostic method adopted.