Seroprevalence survey of bovine Brucellosis in Eastern Algeria: spatial distribution and risk factor analysis. Technical note

Abstract

This cross-sectional study assessed the prevalence of bovine brucellosis and its associated risk factors in the Sétif region of Algeria, which spans diverse agro-climatic zones. Between March and December 2023, blood samples were collected from 391 dairy cows across 32 farms and analyzed using the ID Screen® Brucellosis Serum Indirect Multi-species immunoassay (featuring protein G-HRP conjugate) manufactured by IDVet Innovative Diagnostics (Grabels, France). The study revealed an individual seroprevalence of 30.18% and a herd prevalence of 84.37%, with significant variation across bioclimatic zones. The highest prevalence was observed in the southern zone (41.2%), followed by the highland (30.9%) and northern zones (23.7%). Logistic regression analysis identified external animal introduction (P = 0.0001; OR = 20.3; 95% CI: [5.33-77.19]), infertility (P = 0.0001; OR = 8.6; 95% CI: [3.71-19.89]), and abortion history (P = 0.0001; OR = 8.9; 95% CI:[3.78-20.49]) as primary risk factors. Geographic location wasfound to significantly influence disease risk, with animals inthe northern bioclimatic zone exhibiting a markedly higher likelihood of infection (P = 0.017; OR = 3.0; 95% CI: [1.22-7.54])compared to those in the central region. Throughout the study period, five brucellosis outbreaks were identified, prompting the implementation of targeted control measures, including the culling of 144 seropositive animals and the imposition of restrictions on the distribution of unpasteurized dairy products. These findings highlight the necessity for enhanced control measures for affected herds. The study provides essential epidemiological data to inform evidence-based policies for sustainable brucellosis control in Algeria.