Prevalence and risk factors of Babesia species in domestic herbivores in China: A systematic review and meta-analysis.

Overview

• This study systematically analyzed the prevalence and risk factors of Babesia infection in domestic herbivores (sheep, cattle, and horses) across China using data from 94 studies.
• It identified variations in infection rates by region, species, environmental factors, and animal characteristics, providing insights for targeted disease control.

Background

• Babesia species are protozoan parasites transmitted by ticks that infect a variety of hosts including mammals, birds, and humans.
• The infections cause babesiosis, a disease of veterinary and public health importance worldwide.
• Domestic herbivores such as ovines (sheep), bovines (cattle), and equines (horses) serve as important hosts for Babesia species.
• Understanding the prevalence and risk factors of Babesia in these animals is critical for controlling the disease and reducing economic losses.

Methods

• The authors conducted a systematic review and meta-analysis, searching six databases: PubMed, Web of Science, ScienceDirect, CNKI, Wanfang Data, and VIP Chinese Journal Database.
• Searches included all relevant articles up to 4 November 2024 on Babesia occurrence in domestic herbivores in China.
• Studies were assessed for quality, resulting in 54 high-quality and 40 medium-quality studies from 28 provinces being included.
• Data extracted included prevalence rates, geographic regions, animal species, and environmental or temporal factors.

Key Findings – Prevalence

• Overall pooled prevalence rates of Babesia infection were:
  • 11% in ovines (sheep)
  • 12% in bovines (cattle)
  • 18% in equines (horses)
• Significant variability was observed among different subgroups based on geography, species, environmental conditions, and time factors.

Geographic and Environmental Factors

• Higher infection prevalence was found in East and Central China, notably in Hunan, Fujian, and Ningxia provinces.
• Regions with lower altitude, higher temperature, and greater humidity showed increased Babesia infection rates.
• Longitude and season were significantly associated with infection rates in horses (p < 0.05).
• Temperature significantly affected Babesia infection prevalence in cattle (p < 0.05).

Host Factors and Temporal Trends

• Female animals had higher infection rates compared to males, indicating potential biological or behavioral differences influencing susceptibility.
• Infection rates were higher in samples collected in 2013 or earlier compared to later years, suggesting possible improvements in control measures or surveillance over time.
• The prevalence of different Babesia species varied significantly within bovine hosts, highlighting species-specific epidemiology.

Implications

• The study identifies key epidemiological patterns and risk factors driving Babesia infections in domestic herbivores in China.
• Regional differences suggest environmental factors like temperature, altitude, and humidity play important roles in disease transmission.
• Understanding host-related factors such as sex and temporal trends can aid in targeting interventions more effectively.
• These insights provide a solid foundation for developing tailored prevention and control strategies to reduce babesiosis impact in livestock.

Conclusion

• The systematic review and meta-analysis deliver comprehensive data on Babesia infection prevalence and associated risk factors among sheep, cattle, and horses in China.
• The findings emphasize the need for region-specific and environmentally informed disease management approaches.
• Future work could focus on improving monitoring, tick control, and vaccination strategies adapted to the identified risk profiles.