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Home / Equine Research Bank / Vet Sci / Molecular Identification and Benzimidazole Resistance Analys...
Veterinary sciences2026; 13(2); 169; doi: 10.3390/vetsci13020169

Molecular Identification and Benzimidazole Resistance Analysis of Cyathostomins in Chinese Grazing Horses.

Abstract: This study investigated the cyathostomin species composition, anthelmintic efficacy, and potential resistance-associated mutations in Chinese grazing horses. Fecal samples were collected from 90 adult horses. Fecal egg counts (FECs) were determined using a modified McMaster method. Third stage larvae (L3) cultured from the eggs were identified to species level by PCR amplification and sequencing of the internal transcribed spacer-2 (ITS-2). The main species included and spp. However, differences in the relative abundance of less common species, including and , suggests regional variation. Anthelmintic efficacy was assessed by a fecal egg count reduction test (FECRT) following albendazole administration. Mutations at six codons of the β-tubulin iso-type-1 (tbb-iso-1) gene were screened by gene sequencing. The results showed that, despite harboring an abundant and diverse cyathostomin community, this herd remained susceptible to albendazole. Overall, this study provides baseline data on cyathostomin species composition and anthelmintic susceptibility in horses from China, contributing to global surveillance of equine cyathostomin resistance.
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Publication Date: 2026-02-09 PubMed ID: 41745963PubMed Central: PMC12944989DOI: 10.3390/vetsci13020169Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This research identified the species of cyathostomin parasites in grazing horses in China and evaluated their resistance to benzimidazole class drugs, particularly albendazole.
  • The study combined species identification with tests for drug efficacy and genetic analysis for resistance mutations to understand the parasite community and its susceptibility profile.

Background and Objectives

  • Cyathostomins, also known as small strongyles, are common intestinal parasites affecting horses worldwide and can cause health problems.
  • Effective control relies on anthelmintic drugs such as benzimidazoles, but resistance development poses a threat to equine health management.
  • This study aimed to:
    • Identify cyathostomin species present in grazing horses in China to understand regional parasite diversity.
    • Evaluate the efficacy of albendazole against these parasites through fecal egg count reduction tests (FECRT).
    • Detect genetic mutations associated with benzimidazole resistance in the β-tubulin gene of the parasites.

Methods

  • Sample Collection:
    • Fecal samples were gathered from 90 adult grazing horses in China to get a broad representation of cyathostomin infections.
  • Parasitological Analysis:
    • Fecal egg counts (FECs) were performed using a modified McMaster technique, a standard quantitative method to estimate parasite load.
  • Species Identification:
    • Eggs were cultured to third-stage larvae (L3), allowing morphological and molecular analysis.
    • Polymerase Chain Reaction (PCR) amplification and sequencing targeted the Internal Transcribed Spacer-2 (ITS-2) region of rDNA, a genetic marker useful for species-level identification.
    • Main species identified included dominant and less common genera/species, with regional variations noted in less prevalent species presence.
  • Anthelmintic Efficacy Assessment:
    • The fecal egg count reduction test (FECRT) was conducted post-administration of albendazole to determine the drug’s effectiveness at reducing parasite egg shedding.
  • Resistance Mutation Screening:
    • Sequencing focused on six codons of the β-tubulin iso-type-1 gene, as mutations here are linked to benzimidazole resistance.

Key Findings

  • Diversity and Species Composition:
    • The horse population harbored a diverse cyathostomin community, including both common cyathostomin species and less frequent ones, which varied regionally.
  • Drug Efficacy:
    • Despite the diversity and parasite abundance, the cyathostomin population remained susceptible to albendazole based on FECRT results.
    • This indicates no current clinical resistance in this population to the benzimidazole drug tested.
  • Resistance Genetic Markers:
    • No resistance-associated mutations were detected in the six β-tubulin codons sequenced.
    • This genotypic data supports the phenotypic susceptibility seen in the FECRT.

Conclusions and Implications

  • This study provides important baseline data on the species makeup of cyathostomins in Chinese grazing horses and their current benzimidazole susceptibility.
  • Maintaining effective control of cyathostomins requires ongoing monitoring, and such baseline results help track the emergence of resistance over time.
  • Regional differences in cyathostomin species composition were noted, suggesting that local ecological or management factors influence parasite populations and may affect resistance development patterns.
  • The research contributes to global surveillance efforts by adding data from an underrepresented geographic area.
  • Veterinarians and horse owners can use this information to guide effective parasite control and avoid unnecessary drug use that could promote resistance.

Cite This Article

APA
Zhang C, Cai E, Ma Y, Zhong G, Gao Y, Wu Y, Liu B, Li J. (2026). Molecular Identification and Benzimidazole Resistance Analysis of Cyathostomins in Chinese Grazing Horses. Vet Sci, 13(2), 169. https://doi.org/10.3390/vetsci13020169

Publication

Veterinary sciences
ISSN: 2306-7381
NlmUniqueID: 101680127
Country: Switzerland
Language: English
Volume: 13
Issue: 2
PII: 169

Researcher Affiliations

Zhang, Chenxue
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Cai, Enjia
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Ma, Yuhui
  • Xinjiang Zhaosu County Xiyu Horse Industry Co., Ltd., Zhaosu, Yili 835600, China.
Zhong, Guangzhi
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Gao, Yu
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
  • Dongfangmadu Equine Teaching Hospital, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Wu, Yuhong
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
  • Xinjiang Zhaosu County Xiyu Horse Industry Co., Ltd., Zhaosu, Yili 835600, China.
  • Dongfangmadu Equine Teaching Hospital, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Liu, Bo
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
  • Beijing Zhongnongda Veterinary Hospital Co., Ltd., Beijing 100193, China.
Li, Jing
  • College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
  • Dongfangmadu Equine Teaching Hospital, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
  • State Key Laboratory of Veterinary Public Health and Safety, Beijing 100193, China.

Grant Funding

  • NPRC-2019-194-30 / The National Parasitic Resources Center, the Ministry of Science and Technology Fund
  • 32202861 / The National Natural Science Foundation of China
  • 1051-2224003 / The Talent Fund of China Agricultural University Veterinary Teaching Hospital (Beijing Zhongnongda Veterinary Hospital Co, Ltd)

Conflict of Interest Statement

Authors Yuhui Ma and Yuhong Wu were employed by the Xinjiang Zhaosu County Xiyu Horse Industry Co., Ltd., Bo Liu was employed by the Beijing Zhongnongda Veterinary Hospital Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The sponsors had no role in the design, execution, interpretation, or writing of the study.

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