Seroprevalence and risk factors of brucellosis in Arabian horses

Brucellosis, as a zoonotic disease, mainly occurs in horses by Brucella abortus, Brucella canis and Brucella suis. The disease in equines is often asymptomatic, but the clinical signs in horses are mostly characterized by bursitis, arthritis and tenosynovitis.

This study, thus, aimed to determine the seroprevalence of brucellosis and its associated risk factors in the Arabian horses of Khuzestan province, South-west Iran.

To that end, the blood samples randomly collected from 180 Arabian horses were analyzed for the presence of anti-Brucella antibodies by Rose Bengal plate test (RBPT), serum agglutination test (SAT), 2-mercaptoethanol test (2-ME) and a commercial i-ELISA kit.

The ROC curve analysis showed that the best cut-off point for S/P values in i-ELISA turned out to be 26.25%. The results showed that the overall seroprevalence of brucellosis based on parallel interpretation of the test results was 12.22% (Positive/Tested = 22/180). The prevalence of acute and chronic brucellosis was 8.3 and 3.9%, respectively. The seroprevalence of brucellosis with RBPT and i-ELISA methods was 1.11% (2/180) and 7.22% (13/180), respectively. According to what SAT revealed, 9.44% (17/180) of sera had a titer of 40 or greater, and at 2-ME, 7.22% of samples (13 out of 180 samples) depicted a titer of 40. The results of i-ELISA, SAT and 2-ME were significantly different from those of RBPT (p < 0.01); however, there was no significant difference between i-ELISA, SAT and 2-ME in findings (p > 0.05).

The results of this study recommend that i-ELISA be used for screening purposes of brucellosis in horses. The findings confirmed that Arabian horses are natural hosts for the Brucellae. It is, thus, necessary to adopt appropriate prevention and control programs by health authorities and horse owners so as to reduce the distribution and transmission of the infection in the regions where brucellosis is prevalent.