FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / Vet Parasitol X / Prevalence of Strongylus vulgaris in horses after ten years ...
Veterinary parasitology: X2019; 2; 100013; doi: 10.1016/j.vpoa.2019.100013

Prevalence of Strongylus vulgaris in horses after ten years of prescription usage of anthelmintics in Sweden.

Abstract: Strongylus vulgaris is considered the most pathogenic nematode parasite of the horse. Frequent deworming programs since the 1970s have reduced the prevalence of S. vulgaris to low levels, but to the price of widespread benzimidazole resistance in the small strongyles (cyathostominae) and ivermectin resistance especially in the equine roundworm Parascaris spp. To slow down the progression of anthelmintic resistance in Sweden, horse anthelmintics were made prescription only medicine in 2007 and selective therapy principles were introduced. This means that only individuals with high egg excretion or clinical signs of helminth infection were treated instead of blanket treatment of all horses on a farm. The aims of this study were to investigate the prevalence and risk factors associated with S. vulgaris infection in Sweden ten years after the introduction of a selective therapy regime. A total of 529 faecal samples from 106 farms were collected during March to June in 2016 and 2017. A web-based questionnaire was used to collect information about deworming routines. Strongyle faecal egg counts (FEC) were performed by McMaster and presence of S. vulgaris was demonstrated with a specific PCR on individual larval cultures. Results were analysed by mixed logistic (S. vulgaris prevalence) or linear (FEC) regression models, where farm was included as random factor. The overall prevalence of S. vulgaris at individual and farm levels was 28% and 61%, respectively. We observed a 2.9 increased odds risk of S. vulgaris infection on farms that based their treatment on strongyle FEC only as compared to farms that complemented strongyle FECs with larval cultures or dewormed regularly, 1-4 times per year, without prior diagnosis. We found no association between the prevalence of S. vulgaris and strongyle FEC level, horse age, geographical region or signs of colic. The prevalence of S. vulgaris was 25% in horses shedding ≤150 eggs per gram. Thus horses with low strongyle FECs that are left untreated could be an important source of S. vulgaris infection. This may be an important reason for the approximately three-fold increase in S. vulgaris prevalence since 1999 in Sweden. However, our combined results indicate that selective therapy based on a combination of strongyle FECs and larval cultivation was not associated with an increased risk of S. vulgaris infection. Still, S. vulgaris needs to be monitored continuously and should be taken into careful consideration when the treatment frequency is reduced.
© 2019 The Authors.
Get Full Text
Publication Date: 2019-05-26 PubMed ID: 32904767PubMed Central: PMC7458386DOI: 10.1016/j.vpoa.2019.100013Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

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.

This research investigates the prevalence of the horse parasite Strongylus vulgaris in Sweden, ten years after a policy changed the use of horse de-worming medicine to prescription only.

Research Context

  • The study is based on the Strongylus vulgaris, a nematode parasite considered the most lethal for horses. While deworming programs since the 1970s have somewhat controlled the prevalence of S. vulgaris, they have resulted in a majority of other parasitic species developing resistance to these anthelmintics. Hence, Sweden changed its policy, making anthelmintics for horses prescription-only in 2007, leading to a shift towards selective therapy where only horses showing high egg excretion or symptoms of parasite infection were treated.

Aim and Methodology

  • The purpose of the study was to assess the prevalence of S. vulgaris and the risk factors associated with its infection ten years after implementing the selective therapy regime.
  • The study took place from March to June across 2016 and 2017, and involved collecting and analyzing over 500 faecal samples from 106 different farms. The team also gathered information about the deworming routines on each farm by conducting a web-based survey.
  • A specific PCR test was conducted on individual larval cultures to identify the presence of S. vulgaris.
  • Then the data was computed and analyzed via mixed logistic and linear regression models, which identified patterns, relationships, and prevalence.

Results

  • The study found an overall S. vulgaris prevalence of 28% at an individual level and 61% at farm level. It was revealed that farms that only implemented treatment based on faecal egg count (FEC) analysis had a 2.9 times higher risk of S. vulgaris infection in comparison to farms that also conducted routine lahral culturing or regular deworming.
  • There was no observed relationship between risk factors such as geographic area, horse age or colic symptoms and the prevalence of S. vulgaris.
  • Interestingly, horses with low strongyle FECs (≤150 eggs per gram), which are typically left untreated because they don’t show signs of infection, could be a significant source of S. vulgaris.

Conclusion and Implications

  • The research concluded that selective therapy, which is a combination of strongyle faecal egg counts and larval cultivation, did not associate with an increased risk of S. vulgaris infection.
  • However, due to the observed prevalence of the parasite, continued monitoring of S. vulgaris is needed and must be taken into consideration while determining treatment frequency.
  • This study plays a crucial role in understanding the impacts of different deworming strategies and could lead to improvements in controlling S. vulgaris infections in horses.

Cite This Article

APA
Tydén E, Enemark HL, Franko MA, Höglund J, Osterman-Lind E. (2019). Prevalence of Strongylus vulgaris in horses after ten years of prescription usage of anthelmintics in Sweden. Vet Parasitol X, 2, 100013. https://doi.org/10.1016/j.vpoa.2019.100013

Publication

Veterinary parasitology: X
ISSN: 2590-1389
NlmUniqueID: 101755316
Country: Netherlands
Language: English
Volume: 2
Pages: 100013

Researcher Affiliations

Tydén, Eva
  • Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Uppsala, Sweden.
Enemark, Heidi Larsen
  • Norwegian Veterinary Institute, Department of Animal Health and Food Safety, Oslo, Norway.
Franko, Mikael Andersson
  • Karolinska Institutet, Department of Medical Epidemiology and Biostatistics, Stockholm, Sweden.
Höglund, Johan
  • Swedish University of Agricultural Sciences, Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Uppsala, Sweden.
Osterman-Lind, Eva
  • National Veterinary Institute, Department of Microbiology, Section for Parasitology diagnostics, Uppsala, Sweden.

References

This article includes 38 references
  1. Bellaw LJ, Nielsen KM. Evaluation of Baermann apparatus sedimentation time on recovery of Strongylus vulgaris and S. edentatus third stage larvae from equine coprocultures.. Vet. Parasitol. 2015;211:99–101.
    pubmed: 25976635
  2. Craven J, Bjørn H, Henriksen SA, Nansen P, Larsen M, Lendal S. Survey of anthelmintic resistance on Danish horse farms, using 5 different methods of calculating faecal egg count reduction.. Equine Vet. J. 1998;30:289–293.
    pubmed: 9705110
  3. Coles GC, Bauer C, Borgsteede FH, Geerts S, Klei TR, Taylor MA, Waller PJ. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) methods for the detection of anthelmintic resistance in nematodes of veterinary importance.. Vet. Parasitol. 1992;44:35–44.
    pubmed: 1441190
  4. Drudge JH, Lyons ET. Control of internal parasites of the horse.. J. Am. Vet. Med. Assoc. 1966;148:378–383.
    pubmed: 5950040
  5. Duncan JL. Strongylus vulgaris infection in the horse.. Vet. Rec. 1974;95:34–37.
    pubmed: 4446282
  6. Duncan JL, Pirie HM. The pathogenesis of single experimental infections with Strongylus vulgaris in foals.. Res. Vet. Sci. 1975;18:82–93.
    pubmed: 1118668
  7. Duncan JL, Love S. Preliminary observations on an alternative strategy for the control of horse strongyles.. Equine Vet. J. 1991;23:226–228.
    pubmed: 1909236
  8. Enhäll J. Hästar och anläggningar med häst 2016. Statistiska meddelanden.. .
  9. . 2001/82/EC.. EUR-lex 2018.
  10. Girma K. Försäljning av djurläkemedel.. .
  11. Hinney B, Wirtherle N, Kyule M, Miethe N, Zessin K, Clausen P. A questionnaire survey on helminth control on horse farms in Brandenburg, Germany and the assessment of risks caused by different kinds of management.. Parasitol. Res. 2011;109:1625–1635.
    pubmed: 21559764
  12. Kaplan RM, Nielsen MK. An evidence-based approch to equine parasite control: it ain´t the 60s anymore.. Equine Vet. Educ. 2010;22:306–316.
  13. Kaspar K, Pfister K, Nielsen MK, Silaghi C, Fink H, Scheuerle MC. Detection of Strongylus vulgaris in equine faecal samples by real-time PCR and larval culture – method comparison and occurrence assessment.. BMC Vet. Res. 2017;13:19.
    pmc: PMC5225560pubmed: 28077153
  14. Kenyon F, Greer AW, Coles GC, Cringoli G, Papadopoulos E, Cabaret J, Berrag B, Varady M, Van Wyk JA, Thomas E, Vercruysse J, Jackson F. The role of targeted selective treatments in the development of refugia-based approaches to the control of gastrointestinal nematodes of small ruminants.. Vet. Parasitol. 2009;164:3–11.
    pubmed: 19450930
  15. Lind Osterman E, Höglund J, Ljungström B-L, Nilsson O, Uggla A. A field survey on the distribution of strongyle infections of horses in Sweden and factors affecting faecal egg counts.. Equine Vet. J. 1999;31:68–72.
    pubmed: 9952332
  16. Lind Osterman E, Rautalinko E, Uggla A, Waller PJ, Morrison DA, Höglund J. Parasite control practices on Swedish horse farms.. Acta Vet. Scand. 2007;49:25.
    pmc: PMC2093939pubmed: 17897438
  17. Love S, Duncan JL. Could the worms have turned?. Equine Vet. J. 1991;23:152–154.
    pubmed: 1884693
  18. Martin F, Höglund J, Bergström TF, Karlsson Lindsjö O, Tydén E. Resistance to pyrantel embonate and efficacy of fenbendazole in Parascaris univalens on Swedish stud farms.. Vet. Parasitol. 2018;15:69–73.
    pubmed: 30503095
  19. Molena RA, Peachey LE, Di Cesare A, Traversa D, Cantacessi C. Cyathostomine egg reappearance period following ivermectin treatment in a cohort of UK Thoroughbreds.. Parasit. Vectors. 2018;11:61.
    pmc: PMC5785887pubmed: 29370872
  20. Nilsson O, Andersson T. Stronylus vulgaris hos häst – epizootologi och profylax.. Svensk Veterinärtidning 1979;31:148–156.
  21. Nielsen MK, Monrad J, Olsen SN. Prescription-only anthelmintics - a questionnaire survey on strategies for surveillance and control of equine strongyles in Denmark.. Vet. Parasitol. 2006;135:47–55.
    pubmed: 16309841
  22. Nielsen MK, Peterson DS, Monrad J, Thamsborg SM, Olsen SN, Kaplan RM. Detection and semi-quantification of Strongylus vulgaris DNA in equine faeces by real-time quantitative PCR.. Int. J. Parasitol. 2008;38:443–453.
    pubmed: 17889881
  23. Nielsen MK. Sustainable equine parasite control: perspective and research needed.. Vet. Parasitol. 2012;185:32–44.
    pubmed: 22055611
  24. Nielsen MK, Vidyashankar AN, Olsen SN, Monrad J, Thamsborg SM. Strongylus vulgaris associated with usage of selective therapy on Danish horse farms-is it reemerging?. Vet. Parasitol. 2012;26:260–266.
    pubmed: 22703964
  25. Nielsen MK, Brananb MA, Wiedenheftc AM, Digianantonioc R, Garberb LP, Kopralb CA. Parasite control strategies used by equine owners in the United States: a national survey.. Vet. Parasitol. 2018;250:45–51.
    pubmed: 29329623
  26. Papini RA, De Bernart FM, Sgorbini M. A questionnaire survey on intestinal worm control practices in horses in Italy.. J. Equine Vet. Sci. 2015;35:70–75.
  27. Peregrine AS, Molento MB, Kaplan RM, Nielsen MK. Anthelmintic resistance in important parasites of horses: does it really matter?. Vet. Parasitol. 2014;201:1–8.
    pubmed: 24485565
  28. R Core Team. R: a Language and Environment for Statistical Computing.. .
  29. Schneider S, Pfister K, Becher AM, Scheuerle MC. Strongyle infections and parasitic control strategies in German horses - a risk assessment.. BMC Vet. Res. 2014;10:262.
    pmc: PMC4232665pubmed: 25387542
  30. Slocombe JO, McCraw BM. Gastrointestinal nematodes in horses in Ontario.. Can. Vet. J. 1973;14:101–105.
    pmc: PMC1696110pubmed: 4703606
  31. Slocombe JO, McCraw BM. Controlled tests of ivermectin against migrating Strongylus vulgaris in ponies.. Am. J. Vet. Res. 1981;42:1050–1051.
    pubmed: 6895154
  32. . 17 24 § Legislations (In Swedish). SJVFS 2010.
  33. . Avmaskning Av Häst. (In Swedish). Swedish National Veterinary Institute 2018.
  34. Tolliver SC, Lyons ET, Drudge JH. Prevalence of internal parasites in horses in critical tests of activity of parasiticides over a 28-year period (1956–1983) in Kentucky.. Vet. Parasitol. 1987;23:273–284.
    pubmed: 3564356
  35. Uhlinger C. Uses of fecal egg count data in equine practice.. Comp. Cont. Educ. Vet. Pract. 1993;15:742–749.
  36. Van Wyk JA, Mayhew E. Morphological identification of parasitic nematode infective larvae of small ruminants and cattle: a practical lab guide.. J. Vet. Res. 2013;80:1–14.
    pubmed: 23718204
  37. van Doorn DC, Ploeger HW, Eysker M, Geurden T, Wagenaar JA, Kooyman FN. Cylicocyclus species predominate during shortened egg reappearance period in horses after treatment with ivermectin and moxidectin.. Vet. Parasitol. 2014;206:246–252.
    pubmed: 25458565
  38. von Samson-Himmelstjerna G, Fritzen B, Demeler J, Schurmann S, Rohn K, Schnieder T, Epe C. Cases of reduced cyathostomin egg-reappearance period and failure of Parascaris equorum egg count reduction following ivermectin treatment as well as survey on pyrantel efficacy on German horse farms.. Vet. Parasitol. 2007;144:74–80.
    pubmed: 17112667
Subscribe to our newsletter
Join 99,344 horse owners like you who receive our email updates on horse health and nutrition.