Prevalence of bovine Babesia spp., Anaplasma marginale, and their co-infections in Latin America: Systematic review-meta-analysis.

Bovine parasitic sadness, comprised of the diseases babesiosis and anaplasmosis, has a large impact on cattle farming in several countries, as it compromises animal productivity. Using systematic review (SR)-meta-analysis (MA) methodology, our objective was to summarize and to investigate study characteristics associated with prevalence of Babesia spp. and Anaplasma marginale infection in Latin American cattle herds. Five electronic databases were used. The inclusion criteria were studies that assessed the prevalence of Babesia spp. and A. marginale in cattle in Brazil, Argentina, Uruguay, Paraguay, Colombia, and Mexico. The reported prevalences were converted to logistic scale and summarized using random effects MA. The heterogeneity was assessed, separately, for papers from Brazil and from the remaining countries. A total of 28 papers were included in this MA with a high heterogeneity (I > 95%). The prevalences of A. marginale, Babesia spp., and their co-infections, in Latin America, were 48.9% (95% CI: 30.3-67.8%), 39.8% (95% CI: 24.6-57.2%), and 26.1% (95% CI: 9.1-55.8%), respectively. The prevalence of A. marginale was higher due to the high prevalence of this agent in Mexico (67.1%). In Brazil, the prevalence was 36.6% for A. marginale, 62.6% for Babesia spp., and 8.2% for their co-infections. The North region of Brazil was reported with the highest prevalence for A. marginale (71.9%), while for Babesia spp., the prevalence was considerably divergent between regions, with the highest values also observed in the North region (97.4%), and the lowest in the South region (9.5%). For studies of Babesia spp. in cattle in Latin America, the heterogeneity was mainly explained by the diagnostic method (98.0%), and country (54.8%). When looking at Brazil alone, a similar pattern was observed, but with lower values (i.e., diagnostic method, 31.5%; region, 25.3%; and climate, 12,4%). The evaluated regions presented different levels of prevalence infections, with most of them being classified as high degree of enzootic instability, which can predispose to the occurrence of outbreaks.