Abstract: Equine theileriosis, caused by the protozoan parasite , represents a significant economic threat to the equine industry. In Xinjiang, China, an endemic area for this disease, systematic research on the genetic diversity of has been notably lacking. The aim of this study was to obtain molecular epidemiological data pertaining to the parasite in selected regions of Xinjiang, China, and analyze the genetic characteristics (including rRNA, , and genes) and genotype distribution patterns of isolates from these regions, providing a scientific basis for developing targeted prevention and control strategies. Blood samples were collected from 440 horses across four regions (Altay, Ili, Tacheng, and Urumqi) and subjected to PCR assays. Positive samples were sequenced for phylogenetic and haplotype network analyses, and genetic diversity indices were calculated. The overall infection rate of was 38.41% (169/440), with Tacheng having the highest prevalence (86.27%) and Altay the lowest (20.88%); these regional differences were statistically significant. Phylogenetic analysis identified two genotypes of the rRNA gene: genotype E (predominant) and genotype A. All sequences clustered exclusively within genotype A. Notably, all gene sequences formed a monophyletic group, exhibiting closer genetic relationships to isolates from France and Senegal. This study presents the first comprehensive genotyping of in Xinjiang based on three target genes and constructs an associated haplotype network. The analysis identified rRNA genotype E and genotype A as the predominant genotypes. Furthermore, the genetic diversity of was found to be higher in Urumqi than in the other regions studied.
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Overview
This study investigates the molecular prevalence and genetic diversity of the parasite Theileria equi in horses from Xinjiang, China, using three specific genes to understand infection patterns and genotype distribution for better disease control.
Introduction and Background
Equine theileriosis is a disease caused by the protozoan parasite Theileria equi, which poses significant economic risks to the equine industry worldwide.
The disease is prevalent in Xinjiang, China, but prior to this study, systematic genetic diversity research on T. equi in this region was lacking.
Understanding the genotypic variation and infection rates within different regions helps in formulating targeted prevention and control strategies.
Study Objectives
To obtain molecular epidemiological data on T. equi by sampling horses from various regions in Xinjiang.
To analyze genetic characteristics of the parasite focusing on three genes: 18S rRNA, ema-1, and rap1.
To determine genotype distribution patterns and construct haplotype networks for isolates in the studied regions.
Methodology
Blood samples were collected from 440 horses across four regions in Xinjiang: Altay, Ili, Tacheng, and Urumqi.
Samples underwent PCR assays to detect the presence of T. equi.
Positive PCR samples were sequenced for three genes: 18S rRNA, ema-1, and rap1.
Phylogenetic analyses and haplotype network analyses were conducted to identify genetic relationships and diversity.
Genetic diversity indices were calculated to compare variation among isolates from different regions.
Key Findings
The overall infection rate of T. equi in the sampled horse population was 38.41% (169 out of 440 horses).
Prevalence varied by region: Tacheng showed the highest infection rate at 86.27%, while Altay had the lowest at 20.88%; these differences were statistically significant.
Two genotypes of the 18S rRNA gene were identified: genotype E (predominant) and genotype A.
All ema-1 gene sequences corresponded exclusively to genotype A, indicating less variation in this gene.
All rap1 gene sequences formed a single monophyletic group and showed close genetic relationships with isolates from France and Senegal, suggesting possible global links or similar evolutionary patterns.
The haplotype network constructed using the three genes revealed genotype distribution and genetic relatedness of isolates.
Genetic diversity of T. equi was highest in Urumqi compared to other studied regions, indicating a greater variability of parasite populations here.
Significance of the Study
This research is the first comprehensive study genotyping T. equi in Xinjiang based on multiple gene targets, providing a more detailed understanding of the parasite’s genetic diversity in this endemic region.
The findings highlight regional differences in infection rates and genotypes, which are crucial for designing region-specific disease control measures.
Information on prevalent genotypes (18S rRNA genotype E and ema-1 genotype A) can assist in the development of diagnostic tools and vaccines tailored to the local parasite strains.
The genetic linkage to international isolates suggests potential routes of parasite spread or common evolutionary origins, important for global epidemiological perspectives.
Conclusion
Theileria equi infection is widespread in horses across Xinjiang, with marked regional variation in prevalence and genetic diversity.
Genotyping based on 18S rRNA, ema-1, and rap1 genes reveals a predominance of certain genotypes and notable genetic diversity, especially in Urumqi.
This molecular epidemiological data lays a scientific foundation for targeted control strategies aimed at reducing the impact of equine theileriosis in Xinjiang and potentially similar endemic regions.
Cite This Article
APA
Qin S, Kulabieke T, Mizhamuhan D, Zhang M, Jin M, Abula G, Pi M, Wang H, Zhang Y, Guo Q.
(2025).
Molecular Prevalence and Genotypic Diversity of Theileria equi in Xinjiang, China, Based on Three Genes.
Vet Sci, 13(1), 27.
https://doi.org/10.3390/vetsci13010027
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