Eimeria spp. in Cattle: A Global Systematic Review and Meta-Analysis.

Eimeria spp. are major protozoan parasites of cattle, causing coccidiosis with substantial economic and animal health impacts worldwide. This study systematically reviewed and meta-analysed the global prevalence, species distribution and associated risk factors of Eimeria spp. in cattle. Various international databases were searched from inception to 16 April 2025. Eligible studies reported extractable prevalence data for naturally infected cattle. Pooled prevalence was estimated using a random-effects model, with heterogeneity assessed by I2 statistic. Subgroup analyses were conducted by publication year, continent, country and sample size. Age- and sex-specific data were analysed descriptively due to missing denominators. Genetic diversity and seasonal patterns were summarized descriptively. Meta-regression evaluated sample size, annual precipitation, publication year and national cattle population. Sensitivity analysis and funnel plot (Egger's test) assessed robustness and publication bias. A total of 203 studies including 133,740 cattle from 55 countries were analysed. The global pooled prevalence of Eimeria spp. in cattle was 33.6% (95% confidence interval [CI]: 29.6%-37.8%), with substantial heterogeneity (I2 = 99.4%). Prevalence ranged from 27.1% (2012-2018) to 40.8% (≤2011), 29.5% in Asia to 67.4% in Central America and 1% (Macedonia) to 94.2% (Costa Rica), though some national estimates were based on single studies. Calves <1 year accounted for the highest proportion of positives (56.3%, 95% CI: 46.2-65.8), and females showed higher infection rates (66.7%, 95% CI: 61.7-71.4). Infections peaked during warm and humid periods. Sixteen Eimeria species were identified in cattle; E. bovis and E. zuernii predominated, followed by E. auburnensis, E. ellipsoidalis, E. cylindrica and E. alabamensis. Sensitivity analyses confirmed estimate stability. Meta-regression identified sample size as the only significant predictor, explaining 4% of heterogeneity. Publication bias was detected (p < 0.05). Eimeria infection imposes a substantial global burden in cattle, particularly among calves and females. Although sample size influenced reported prevalence, marked heterogeneity persists. Standardized reporting and geographically balanced studies are needed to better inform global coccidiosis control strategies.