Comprehensive Meta-Analysis of Brucellosis in Wild and Domestic Birds: Unraveling the Complex Interplay of Transmission and Ecology (1970-2024).

Brucellosis is a zoonotic infection caused by Brucella species, primarily affecting livestock, but with a wider host range that includes marine animals, amphibians, and possibly birds. This article aimed to conduct a meta-analysis of studies on avian brucellosis from 1970 to 2024, to define the role of wild and avian birds in the transmission and ecology of Brucella species. The analysis of 16,135 wild and domestic bird samples did not detect Brucella species (prevalence: 0%; 95% CI: 0.00% to 16.00%), although the wide confidence interval (CI) and moderate heterogeneity suggest uncertainty in the true prevalence. Furthermore, domestic birds exhibited a significantly higher prevalence of 1.31% (CI: 0.51%-2.35%), with very high heterogeneity. Moreover, females exhibited a prevalence of 0.1% (CI: 0.00%-0.52%), with no significant heterogeneity, indicating consistency among studies. Males presented a slightly lower prevalence (0.07%, CI: 0.00%-0.26%) and similarly displayed no heterogeneity. The results indicated that, even though birds are seropositive for brucellosis, their contribution to the natural transmission of the disease is minimal, particularly among domestic species. We note a variation in prevalence depending on the type of bird and the geographic region, with higher prevalence among domestic birds. Significant heterogeneity in infection rates was observed, reflecting complex epidemiological features. Results showed that birds may act as vectors for Brucella species, but further studies are needed to establish their role in transmitting the disease.