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International journal for parasitology. Parasites and wildlife2020; 11; 183-190; doi: 10.1016/j.ijppaw.2020.02.002

Not playing by the rules: Unusual patterns in the epidemiology of parasites in a natural population of feral horses (Equus caballus) on Sable Island, Canada.

Abstract: Sable Island, Nova Scotia, Canada hosts one of few natural populations of feral horses (Equus caballus) never exposed to anthelmintics. Coproculture revealed cyathostomes, Strongylus equinus, S. edentatus, and S. vulgaris, with S. equinus (unusually) dominating in adult horses and cyathostomes dominating in young horses (<3 years of age). We examined 35 horses found dead in the springs of 2017 and 2018, as well as fecal samples from live horses in spring (n = 45) and summer 2018 (n = 236) using McMaster fecal flotation and Baermann larval sedimentation on fresh samples, and modified Wisconsin flotation and sucrose gradient immunofluorescent assay for Giardia and Cryptosporidium on frozen samples. Mean strongyle fecal egg counts were 666 eggs per gram (EPG) in dead horses, 689 EPG in live horses in spring, and 1105 EPG in summer; domestic horses are usually treated at counts exceeding 200 EPG. Adult horses (unusually) had patent infections with the lungworm Dictyocaulus arnfieldi and ascarids (Parascaris spp.), and in spring, dead horses had 5 times higher odds of having patent ascarid infections than live horses, likely due to malnutrition and corresponding immunodeficiency. Fecal prevalence and intensity of D. arnfieldi and Parascaris spp. were significantly higher in young horses, and in spring versus summer. A higher proportion of fecal samples were positive for strongyle and ascarid eggs using a centrifugal flotation technique on previously frozen feces, as compared to a passive flotation method on fresh feces. Eggs of the tapeworm Paranoplocephala mamillana were present in fecal samples from 28% of live, and 42% of dead, horses in spring. This research represents several new geographic records (S. edentatus, D. arnfieldi, and Eimeria leuckarti), provides insight into unusual patterns of parasite epidemiology in a nutrition-limited environment, and has conservation and biosecurity implications for this unique equine population, as well as for parasite management in domestic horses.
Crown Copyright © 2020 Published by Elsevier Ltd on behalf of Australian Society for Parasitology.
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Publication Date: 2020-02-05 PubMed ID: 32095427PubMed Central: PMC7033351DOI: 10.1016/j.ijppaw.2020.02.002Google 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.

The research looks into the unusual patterns of parasite epidemiology in a naturally occurring population of feral horses on Sable Island, Canada, a location not impacted by anthelmintics. Notably, the dominating parasites were different in adult horses and young horses, and the findings provide new geographic records of certain parasites, along with insights about how nutrition-limited environments can affect parasite epidemiology, which is important for the conservation and biosecurity of the unique horse population and the management of parasites in domestic horses.

Methodology

  • The team used coproculture to find out that the dominant parasites in adult and young horses are cyathostomes and Strongylus vulgaris respectively.
  • The researchers examined 35 horses that were found dead in the springs of 2017 and 2018, alongside feces samples from live horses gathered in spring and summer, using techniques such as McMaster fecal flotation and Baermann larval sedimentation on fresh samples, and modified Wisconsin flotation and sucrose gradient immunofluorescent assay for Strongyles and Ascarids on frozen samples.

Findings

  • The mean strongyle fecal egg counts were 666 eggs per gram (EPG) in dead horses, 689 EPG in live horses in spring, and 1105 EPG in summer; for comparison, domestic horses usually receive treatments when the count exceeds 200 EPG.
  • It was found that adult horses had patent infections with the lungworm Dictyocaulus arnfieldi and ascarids, particularly in spring. The dead horses had 5 times higher odds of having patent ascarid infections than the live ones, a trend that is likely due to malnutrition and corresponding immunodeficiency.
  • The fecal prevalence and intensity of Strongylus vulgaris and Ascarids spp. were significantly higher in young horses, and in spring versus summer.
  • Eggs of the tapeworm Anoplocephala perfoliata were present in fecal samples from 28% of the live horses, and 42% of the dead, during spring.

Implications

  • The research results contribute a number of new geographic records. For instance, Strongylus vulgaris and Dictyocaulus arnfieldi being present in the local horse population.
  • The unique patterns of parasite epidemiology revealed by the study offer insight into how environments that are limited in nutrition can have an effect on parasitic infections.
  • The findings carry implications for the conservation and biosecurity of the unique horse population and can influence how parasites are managed in domestic horses.

Cite This Article

APA
Jenkins E, Backwell AL, Bellaw J, Colpitts J, Liboiron A, McRuer D, Medill S, Parker S, Shury T, Smith M, Tschritter C, Wagner B, Poissant J, McLoughlin P. (2020). Not playing by the rules: Unusual patterns in the epidemiology of parasites in a natural population of feral horses (Equus caballus) on Sable Island, Canada. Int J Parasitol Parasites Wildl, 11, 183-190. https://doi.org/10.1016/j.ijppaw.2020.02.002

Publication

International journal for parasitology. Parasites and wildlife
ISSN: 2213-2244
NlmUniqueID: 101599824
Country: England
Language: English
Volume: 11
Pages: 183-190

Researcher Affiliations

Jenkins, Emily
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
Backwell, Amber-Lynn
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
Bellaw, Jennifer
  • M.H. Gluck Equine Research Center, University of Kentucky, 1400 Nicholasville Road, Lexington, KY, 40546, USA.
Colpitts, Julie
  • Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada.
Liboiron, Alice
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
McRuer, David
  • Parks Canada Agency, Government of Canada, 30 Victoria Street, Gatineau, Q, J8X 0B3, Canada.
Medill, Sarah
  • Parks Canada Agency, Government of Canada, 30 Victoria Street, Gatineau, Q, J8X 0B3, Canada.
Parker, Sarah
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
Shury, Todd
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
  • Parks Canada Agency, Government of Canada, 30 Victoria Street, Gatineau, Q, J8X 0B3, Canada.
Smith, Martha
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
Tschritter, Christina
  • Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada.
Wagner, Brent
  • Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, S7N 5B4, Canada.
Poissant, Jocelyn
  • Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada.
McLoughlin, Philip
  • Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada.

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Citations

This article has been cited 11 times.
  1. Ochigbo GO, Ahn S, Belhumeur KA, Poissant J, Rosa BV. Nemabiome sequencing reveals seasonal and age associated patterns of strongyle infection and high prevalence of Strongylus vulgaris in Alberta feral horses. Int J Parasitol Parasites Wildl 2025 Aug;27:101091.
    doi: 10.1016/j.ijppaw.2025.101091pubmed: 40524829google scholar: lookup
  2. Ahn S, Redman EM, Gavriliuc S, Bellaw J, Gilleard JS, McLoughlin PD, Poissant J. Mixed strongyle parasite infections vary across host age and space in a population of feral horses. Parasitology 2024 Oct;151(12):1299-1316.
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  3. Stothart MR, McLoughlin PD, Medill SA, Greuel RJ, Wilson AJ, Poissant J. Methanogenic patterns in the gut microbiome are associated with survival in a population of feral horses. Nat Commun 2024 Jul 22;15(1):6012.
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  4. Górecka-Bruzda A, Siemieniuch M, Lansade L, Stanley CR. How Useful Are Existing Protocols in the Quick Assessment of the Welfare of Semi-Feral Horses? Pilot Study on Konik Polski Horses Living in the Forest Sanctuary. Animals (Basel) 2023 Dec 19;14(1).
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