Seroepidemiology and molecular detection of Brucella infection in Iranian horses: Aprovincial study

Brucellosis is a febrile zoonotic infection and has worldwide distribution among humans as well as animals. Although the seroprevalence of brucellosis in various animals has been described in Iran, there is only one report on equine brucellosis in the region. This study was carried out to determine the seroprevalence of brucellosis in racing clubs and private horse owners in the south of Iran and risk factors associated with the disease in horses. 312 randomly selected equine serum samples were investigated for the presence of antibodies against Brucella genus, using slide agglutination by Rose Bengal plate test (RBPT), serum agglutination test (SAT) and 2 mercaptoethanol (2-ME) test, using whole cell antigen. PCR assay was also used for detection of clinically suspected cases. Most seropositive horses in this study were asymptomatic. The true seroprevalence of brucellosis was found to be 9.9, 8 and 7% by RBPT, SAT and 2- mercaptoethanol tests, respectively. All horses with history of clinical signs (3.2% of all samples) had RBPT, SAT and 2- mercaptoethanol positive results. It was also revealed that age, sex and a history of contact with ruminants had no effect on acquiring the infection in positive cases. In the PCR, one of the three horses with fistula withers produced amplicon of 450 bp fragment of wbo sequences specific to Brucella spp. field strain. This study showed the seroprevalence of brucellosis in horses of Fars province and it was indicated that the PCR assay may be helpful in detection of clinically suspected horses.