Molecular prevalence and genotypic diversity of Theileria equi and Babesia caballi infecting horses in Kyrgyzstan.

Overview

• This study investigated the presence and genetic diversity of two parasites, Theileria equi and Babesia caballi, which cause equine piroplasmosis, in horses across Kyrgyzstan.
• The research identified infection rates and genotypes of these parasites, highlighting potential disease risks and the complexity of control efforts in the region.

Background

• Equine piroplasmosis is a disease affecting horses, caused by hemoprotozoan parasites Theileria equi and Babesia caballi.
• These parasites infect red blood cells, leading to clinical symptoms that can adversely affect horse health and performance.
• Understanding how widespread these infections are, and which genotypes of the parasites are present, is important for managing and controlling the disease effectively.
• Kyrgyzstan, a country with significant horse populations, had no previous comprehensive surveys to determine the prevalence and diversity of these parasites.

Study Objectives

• To detect infections of T. equi and B. caballi among horses in all seven provinces of Kyrgyzstan.
• To analyze the genotypic diversity of these parasites using molecular methods.
• To evaluate the epidemiological status of equine piroplasmosis in the country.

Methodology

• Sample Collection:
  • Blood samples were collected from 226 horses distributed across all provinces—Chuy, Issyk-Kul, Naryn, Talas, Jalal-Abad, Osh, and Batken.
• DNA Extraction and PCR:
  • DNA was extracted from the blood samples to allow detection of parasite DNA.
  • Specific Polymerase Chain Reaction (PCR) assays targeted the DNA of T. equi and B. caballi to confirm infection.
• Genotyping:
  • For T. equi-positive samples, genotype-specific PCR assays identified five genotypes (A, B, C/Theileria haneyi, D, E).
  • For B. caballi, rap-1 gene sequencing and phylogenetic analysis discerned genotypes A and B1.

Results

• Prevalence:
  • 24.8% (56 out of 226) horses tested positive for T. equi, with a confidence interval of 19.6% to 30.8%.
  • 3.1% (7 out of 226) were positive for B. caballi, with a confidence interval of 1.5% to 6.3%.
  • T. equi was detected in all seven provinces, indicating widespread distribution.
  • B. caballi was present in five provinces, absent only in Talas and Osh.
• Genotypic Diversity:
  • T. equi-positive horses carried all five known genotypes (A, B, C, D, E), demonstrating high genetic diversity.
  • B. caballi isolates grouped into genotypes A and B1, signifying the presence of at least two genetic variants.

Implications and Significance

• The observed infection rates suggest that equine piroplasmosis poses a significant health risk to horses in Kyrgyzstan.
• The presence of multiple parasite genotypes complicates diagnosis, treatment, and vaccination strategies, as different genotypes may vary in pathogenicity and response to interventions.
• Widespread infection of T. equi across all provinces underscores a likely endemic status requiring immediate attention.
• The uneven distribution of B. caballi suggests environmental or vector-related factors influencing parasite spread.
• Data generated serves as a baseline for future epidemiological monitoring and the development of targeted control programs, such as vector control, drug administration, and breeding management.

Conclusion

• This study fills a knowledge gap regarding the status of equine piroplasmosis in Kyrgyzstan by providing molecular evidence of infection and parasite diversity.
• The high prevalence and genotypic variation call for comprehensive and region-wide surveillance and control measures to safeguard the equine population.
• Efforts to mitigate equine piroplasmosis will be critical for maintaining horse health, supporting local economies, and preventing potential disease outbreaks.