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International journal for parasitology. Drugs and drug resistance2025; 29; 100622; doi: 10.1016/j.ijpddr.2025.100622

Recent advances in intestinal helminth parasites of horses in the Asia-Pacific region: Current trends, challenges and future directions.

Abstract: Over the past 25 years, significant progress has been made in understanding and managing equine gastrointestinal parasites in the Asia-Pacific region, particularly in Australia and New Zealand. This review synthesises current knowledge of the epidemiology, diagnostic methods, anthelmintic resistance (AR), and control strategies for major equine intestinal parasites, including cyathostomins, Parascaris spp., Anoplocephala perfoliata, and Strongyloides westeri. Recent studies highlight substantial regional variation in parasite prevalence, egg shedding and cyathostomin population composition, shaped by diverse climatic conditions. Of increasing concern is the emergence of resistance to commonly used anthelmintics which is now evident in both Parascaris and cyathostomins, although data for S. westeri and A. perfoliata remain limited. High-throughput molecular diagnostics, such as next-generation sequencing, have advanced species-level characterisation in Australia and Thailand. ELISA-based tests for A. perfoliata and encysted cyathostomins are promising but remain unvalidated and underutilised regionally. The routine use of combination anthelmintics, including benzimidazoles, praziquantel, pyrimidines, and macrocyclic lactones, may accelerate resistance across nematode and cestode populations, emphasising the need for regular efficacy monitoring and improved antiparasitic stewardship. Findings from recent research on horse parasites in Australia have informed the development of country's first national equine parasite control guidelines which recommend targeted or selective treatment strategies. However, the effectiveness of these strategies requires ongoing evaluation, particularly in year-round grazing systems in tropical and subtropical regions. Sustainable parasite control will depend on the integration of non-chemical strategies along with the use of anthelmintics and the establishment of a national parasite surveillance database. This review highlights the need for climate-specific treatment protocols, strengthened collaborative research infrastructure, and continued investment in innovative diagnostic and control methods to preserve equine health and anthelmintic efficacy across the region.
Copyright © 2025 The Authors. Published by Elsevier Ltd.. All rights reserved.
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Publication Date: 2025-10-17 PubMed ID: 41135277PubMed Central: PMC12593687DOI: 10.1016/j.ijpddr.2025.100622Google 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 article reviews the latest progress and challenges in understanding, diagnosing, and controlling intestinal helminth parasites in horses within the Asia-Pacific region over the past 25 years.
  • It focuses on key parasites affecting horses, the issue of drug resistance, advances in diagnostics, and future directions for sustainable parasite management.

Background and Regional Context

  • The Asia-Pacific region, especially Australia and New Zealand, has seen significant strides in research on equine gastrointestinal parasites.
  • There is notable variability in parasite presence and behavior across this region, largely due to diverse climates ranging from tropical to temperate zones.
  • The major equine intestinal parasites discussed include:
    • Cyathostomins (small strongyles)
    • Parascaris species (roundworms)
    • Anoplocephala perfoliata (tapeworm)
    • Strongyloides westeri (threadworm)

Epidemiology and Parasite Population Dynamics

  • Parasite prevalence and egg shedding rates vary considerably within the region depending on local environmental conditions.
  • The composition of cyathostomin populations shows regional differences, influenced by climate and grazing practices.
  • Such ecological variation impacts parasite transmission cycles, infection intensities, and treatment outcomes.

Emergence of Anthelmintic Resistance (AR)

  • A growing concern is the detection of resistance to primary classes of anthelmintics used to treat these parasites.
  • Resistance is now documented in both Parascaris spp. and cyathostomins, complicating control efforts.
  • Limited data currently exist on resistance patterns in Strongyloides westeri and Anoplocephala perfoliata.
  • The widespread and routine use of combination anthelmintics (including benzimidazoles, praziquantel, pyrimidines, macrocyclic lactones) may further drive resistance development.

Advances in Diagnostic Methods

  • High-throughput molecular diagnostics like next-generation sequencing have enabled precise species-level parasite identification, notably in studies from Australia and Thailand.
  • Enzyme-linked immunosorbent assays (ELISA) targeting A. perfoliata and encysted cyathostomin stages show promise for improved detection but remain largely unvalidated and underused in the region.
  • Improved diagnostics are critical for guiding targeted treatment and reducing unnecessary anthelmintic application.

Control Strategies and Guidelines

  • Australia has developed the first national equine parasite control guidelines informed by recent research findings.
  • These guidelines emphasize targeted or selective treatment strategies rather than blanket deworming to slow resistance emergence.
  • Effectiveness of such strategies requires ongoing validation, especially considering year-round grazing in tropical and subtropical climates where parasite exposure is continuous.
  • Sustainable control involves integrating non-chemical interventions along with strategic anthelmintic use.

Future Directions and Recommendations

  • Establish a national parasite surveillance database to track infection trends and resistance development.
  • Develop climate-specific treatment protocols tailored to local parasite epidemiology and transmission dynamics.
  • Strengthen collaborative research infrastructure across Asia-Pacific to facilitate data sharing and coordinated studies.
  • Invest in novel diagnostic tools and alternative control methods to lessen reliance on chemical treatments.
  • Promote judicious anthelmintic stewardship to preserve drug efficacy and protect equine health.

Significance

  • This review consolidates comprehensive region-specific knowledge on equine intestinal parasites.
  • It highlights the urgent need to adapt strategies to changing parasite drug resistance landscapes and environmental factors.
  • By emphasizing integrated, evidence-based approaches and monitoring, it guides veterinarians and horse owners towards more sustainable parasite management.
  • Ensuring effective parasite control is vital for maintaining horse health, performance, and welfare in the Asia-Pacific region.

Cite This Article

APA
Abbas G, Nielsen MK, E-Hage C, Ghafar A, Beveridge I, Bauquier J, Beasley A, Wilkes EJA, Carrigan P, Cudmore L, Jacobson C, Hughes KJ, Jabbar A. (2025). Recent advances in intestinal helminth parasites of horses in the Asia-Pacific region: Current trends, challenges and future directions. Int J Parasitol Drugs Drug Resist, 29, 100622. https://doi.org/10.1016/j.ijpddr.2025.100622

Publication

International journal for parasitology. Drugs and drug resistance
ISSN: 2211-3207
NlmUniqueID: 101576715
Country: Netherlands
Language: English
Volume: 29
Pages: 100622
PII: 100622

Researcher Affiliations

Abbas, Ghazanfar
  • Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, Australia.
Nielsen, Martin K
  • Department of Animal and Veterinary Sciences, Aarhus University, Tjele, Denmark.
E-Hage, Charles
  • Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, Australia.
Ghafar, Abdul
  • Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, Australia.
Beveridge, Ian
  • Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, Australia.
Bauquier, Jenni
  • Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, Australia.
Beasley, Anne
  • School of Agriculture and Food Sustainability, The University of Queensland, Gatton, Queensland, Australia.
Wilkes, Edwina J A
  • Racing Victoria, Flemington, Victoria, 3031, Australia.
Carrigan, Peter
  • Scone Equine Hospital, Scone, New South Wales, 2337, Australia.
Cudmore, Lucy
  • Scone Equine Hospital, Scone, New South Wales, 2337, Australia.
Jacobson, Caroline
  • Centre for Animal Production and Health, Murdoch University, Murdoch, Western Australia, 6150, Australia.
Hughes, Kristopher J
  • School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.
Jabbar, Abdul
  • Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, Australia. Electronic address: jabbara@unimelb.edu.au.

MeSH Terms

  • Animals
  • Horses
  • Anthelmintics / therapeutic use
  • Anthelmintics / pharmacology
  • Helminthiasis, Animal / epidemiology
  • Helminthiasis, Animal / drug therapy
  • Helminthiasis, Animal / diagnosis
  • Helminthiasis, Animal / parasitology
  • Horse Diseases / epidemiology
  • Horse Diseases / parasitology
  • Horse Diseases / drug therapy
  • Horse Diseases / diagnosis
  • Intestinal Diseases, Parasitic / veterinary
  • Intestinal Diseases, Parasitic / epidemiology
  • Intestinal Diseases, Parasitic / drug therapy
  • Intestinal Diseases, Parasitic / diagnosis
  • Intestinal Diseases, Parasitic / parasitology
  • Australia / epidemiology
  • Helminths / drug effects
  • Helminths / isolation & purification
  • Drug Resistance
  • Asia / epidemiology
  • New Zealand / epidemiology
  • Prevalence

Conflict of Interest Statement

Declaration of competing interests The authors of this manuscript are members of the Australian Equine Parasitology Advisory Panel (AEPAP), including Abdul Jabbar, Ghazanfar Abbas, Jenni Bauquier, Charles El-Hage, Abdul Ghafar and Ian Beveridge (The University of Melbourne), Anne Beasley (University of Queensland), Kristopher Hughes (Charles Sturt University), Caroline Jacobson (Murdoch University), Edwina Wilkes (Racing Victoria), and Peter Carrigan and Lucy Cudmore (Scone Equine Hospital). Boehringer Ingelheim supported the panel. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work or views reported in this paper.

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