Prevalence of, and risk factors for, brucellosis in Awassi sheep in Southern Jordan

A cross-sectional study was carried out during the period between July 2003 and June 2005 to investigate the epidemiology of ovine brucellosis in Southern Jordan. Serum samples from 1380 sheep corresponding to 66 flocks were collected and analyzed using rose bengal plate test and complement fixation test. A structured questionnaire was used to collect information on sheep health and management. Risk factors for Brucella seropositivity were investigated using a multivariable logistic regression model. In addition, the incidence of Brucella-specific abortion was investigated in 12 sheep flocks located in Karak (a governorate in the southern part of Jordan). The true prevalence of Brucella-seropositive sheep was 37.6%. Out of the 66 investigated sheep flocks, 31 (47%) had at least one positive animal. The prevalence of brucellosis in sheep was significantly higher (P < 0.05) in Ma’an governorates than that in the other governorates. The multivariable logistic regression model identified addition of new animals (OR = 2.8; 95% CI: 2.1, 3.8), contact with other sheep flocks (OR = 1.8; 95% CI: 1.3, 2.7) and lending lambs during breeding season (OR = 1.9; 95% CI: 1.2, 3.1) as risk factors. On the other hand, vaccination with Rev-1 vaccine (OR = 1.7; 95% CI: 1.1, 3.0) was identified as a protective factor.