Brucellosis seroprevalence in captive scimitar-horned oryx (Oryx dammah) in the United Arab Emirates and associated risk factors

Abstract

Background: The scimitar‐horned oryx (Oryx dammah) (SHO) is a large African antelope that became extinct in the wild just over two decades ago. Conservation of the species is of prime importance, but it might face pathogen stressors.<p> <p>Methods and principal findings: Brucella melitensis biovar 1 was previously confirmed in a high‐density captive population of SHO held in Abu‐Dhabi emirate. The infection reached 67.0 % (95 % CI: 64.0–70.0) individual seroprevalence (n = 959) during testing performed between January 2013 and January 2015. A model based on a multivariable logistic regression analysis showed that the seroprevalence ranged from 51.2 (95 % CI: 39.6–62.7) to 86.9 % (95 % CI: 82.4–91.4) between six different enclosures, and probability of being seropositive was 1.83 (95 % CI: 1.32–2.55) higher in females than in males, 3.09 (95 % CI: 1.66–5.91) and 9.35 (95 % CI: 4.66–19.44) higher in subadults and adults than in juveniles, respectively. The three serological tests used in this study (Rose Bengal Test, lateral flow assay and in‐house i‐ELISA) had a perfect or near‐perfect agreement (Cohen’s Kappa coefficient >=0.97). Recurrent high seroprevalence in time and congruence of results from three different serological tests point toward a persistent B. melitensis infection in a high‐density captive SHO population. <p>Conclusion and significance Testing strategy (Bengal Test, lateral flow assay or in‐house i‐ELISA) has no effect on the estimation of the brucellosis seroprevalence in SHO permitting the selection of a practical test. We call for an evidence‐based control program, and Brucella vaccine efficacy and innocuity studies in this endangered species.