Systematic Review and Meta-Analysis of the Prevalence, Species Distribution and Risk Factors of Eimeria spp. in Iranian Livestock.

BACKGROUND

Eimeria spp. are protozoan parasites causing coccidiosis, a disease that leads to significant economic losses in livestock such as cattle, water buffalo, sheep and goats. This systematic review and meta-analysis assessed the prevalence and distribution of Eimeria species in Iranian livestock to better understand the epidemiology of this parasitic infection.

METHODS

A comprehensive literature search was conducted in international and Persian databases for studies published from 1 January 2000 to 7 October 2024. Data on prevalence rates, sample sizes, age groups, genders, seasons, species identification and geographical distribution were analysed using a random-effects model, with subgroup and meta-regression analyses to identify potential sources of heterogeneity. A sensitivity analysis was conducted to evaluate the robustness of the results.

RESULTS

This systematic review included 25 studies comprising 29 datasets: 12 on sheep, 8 on cattle, 7 on goats and 2 on water buffalo. The overall weighted prevalence of Eimeria spp. in Iranian livestock was 45% (95% CI: 32.9%-57.6%). Species-specific pooled prevalence rates were highest in water buffalo (92.7%), followed by goats (75.6%), sheep (47%) and cattle (19.1%). Younger animals (under 1 year) showed a higher prevalence (65.2%) compared to older ones (48.8%), with an odds ratio (OR) of 2.03 (95% CI: 1.33-3.08), indicating increased susceptibility in younger livestock. Females exhibited slightly higher infection rates (42.9%) than males (42.7%), and prevalence peaked during spring and winter. A total of 35 Eimeria species were identified across Iranian livestock. Water buffalo had 14 species, with E. bovis and E. zuernii being the most common. Cattle and sheep each had 13 species, with E. bovis and E. zuernii predominating in cattle and E. intricata, E. ahsata, E. ovinoidalis and E. faurei predominating in sheep, while goats had 12, with E. arloingi, E. ninakohlyakimovae and E. christenseni being predominant in goats.

CONCLUSIONS

The findings highlight the critical need for effective control and prevention strategies to mitigate the health and economic impacts of Eimeria spp. infections in Iranian livestock.