FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / Parasitol Res / Population-S benzimidazole- and tetrahydropyrimidine-resista...
Parasitology research2003; 91(5); 407-411; doi: 10.1007/s00436-003-0983-6

Population-S benzimidazole- and tetrahydropyrimidine-resistant small strongyles in a pony herd in Kentucky (1977-1999): effects of anthelmintic treatment on the parasites as determined in critical tests.

Abstract: Population-S small strongyles have been studied since 1974 in central Kentucky in a closed Shetland pony breeding herd. The ponies were treated approximately every 8 weeks with cambendazole (1974-1978), oxibendazole (OBZ) (1978-1992), or pyrantel pamoate (PRT) (1992-1999). Small strongyles in the ponies have shown resistance to these compounds in field and critical tests. One purpose of this presentation was to compare different parameters for determination of effects on the small strongyle species in ponies after treatment, mainly with OBZ or PRT, from data in critical tests (n=112). Also, the objective was to report on relative changes in the composition of species of small strongyles during the period 1977 through 1999. The following entities were compared to evaluate the effect of OBZ- or PRT-treatment on the small strongyles: (1) numbers of specimens with eggs in utero--there were less gravid worms passed in the feces than recovered at necropsy for OBZ but the numbers of gravid worms were similar in both categories for PRT, (2) pre- and posttreatment counts of eggs per gram of feces (EPGs) and larvae per gram of feces (LPGs)--the reductions were greater for the counts of EPGs than LPGs for OBZ but not for PRT, and (3) pre- and posttreatment counts of EPGs versus % of worms removed--reductions of the former were greater than the latter for both compounds. As shown from data in this study, reduction of EPG counts post treatment indicated much greater drug activity than was actually demonstrated by removal of worms. One evident factor was the value of doing critical tests to verify posttreatment counts of EPGs as indicators of anthelmintic activity. Twenty-eight species of small strongyles were found. For the 20 most prevalent species in the study, two decreased, five remained unchanged, three increased and then became stationary, five increased but then decreased, and five increased progressively. Numbers of small strongyles were highest in 1987 and 1999.
Get Full Text
Publication Date: 2003-10-07 PubMed ID: 14530968DOI: 10.1007/s00436-003-0983-6Google 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
  • Research Support
  • Non-U.S. Gov't

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 article focuses on the study of population-S small strongyles in a closed Shetland pony breeding herd. The study, carried out in central Kentucky from 1974 to 1999, evaluated the effects of various anthelmintic treatments on the parasites and the relative changes in the composition of small strongyle species over this period.

Research Methodology

  • The study examined small strongyles in a Shetland pony herd from 1974 to 1999, wherein the ponies were periodically treated with different anthelmintics: cambendazole (1974-1978), oxibendazole (OBZ) (1978-1992), or pyrantel pamoate (PRT) (1992-1999).
  • The effects of these treatments on the small strongyle species were analyzed based on data from critical tests.
  • The treatment effects were evaluated in terms of (1) the numbers of gravid worms passed in feces and recovered at necropsy, (2) reductions in egg and larva counts per gram of feces before and after treatment, and (3) reduction percentages in egg counts versus worm removal.
  • The study also tracked the changes in the composition of small strongyle species over the 22-year period.

Key Findings

  • The researchers observed that the posttreatment reductions in egg counts were greater than those in larva counts with OBZ, but not with PRT. Further, the reductions in egg counts were also greater than the actual worm removal rate for both anthelmintics.
  • The results indicated that egg count reductions post treatment suggested a higher drug activity than what was actually reflected in worm removal – underscoring the value of critical tests for properly assessing anthelmintic activity.
  • Over the course of the study, a total of 28 species of small strongyles were identified. Of the 20 most prevalent species, two decreased, three initially increased and then plateaued, five increased but subsequently decreased, five continuously increased, while five had no significant change over time.
  • The highest numbers of small strongyles were recorded in 1987 and 1999.

Implications

  • The study provides important insights into the relative efficacy of different anthelmintic treatments on small strongyles and the need for more precise or additional measures beyond egg and larva counts to assess treatment effectiveness.
  • The findings can guide future research and development of more effective treatments for gastrointestinal parasites in equine health.

Cite This Article

APA
Lyons E. (2003). Population-S benzimidazole- and tetrahydropyrimidine-resistant small strongyles in a pony herd in Kentucky (1977-1999): effects of anthelmintic treatment on the parasites as determined in critical tests. Parasitol Res, 91(5), 407-411. https://doi.org/10.1007/s00436-003-0983-6

Publication

Parasitology research
ISSN: 0932-0113
NlmUniqueID: 8703571
Country: Germany
Language: English
Volume: 91
Issue: 5
Pages: 407-411

Researcher Affiliations

Lyons, Eugene
  • Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546-0099, USA. elyons1@uky.edu

MeSH Terms

  • Animals
  • Antinematodal Agents / pharmacology
  • Antinematodal Agents / therapeutic use
  • Benzimidazoles / pharmacology
  • Benzimidazoles / therapeutic use
  • Drug Resistance / drug effects
  • Feces / parasitology
  • Female
  • Horses
  • Kentucky
  • Parasite Egg Count / veterinary
  • Pyrantel Pamoate / pharmacology
  • Pyrantel Pamoate / therapeutic use
  • Strongyle Infections, Equine / drug therapy
  • Strongyle Infections, Equine / parasitology
  • Strongylus / classification
  • Strongylus / drug effects
  • Strongylus / isolation & purification

References

This article includes 8 references
  1. Lyons ET, Drudge JH, Tolliver SC, Swerczek TW, Stamper S, Granstrom DE. Control of cambendazole-resistant small strongyles (Population S) with oxibendazole in a pony band: an 8 year field test (1984-1992).. Vet Parasitol 1994 Apr;52(3-4):271-7.
    pubmed: 8073610doi: 10.1016/0304-4017(94)90118-xgoogle scholar: lookup
  2. Lyons ET, Tolliver SC, Drudge JH, Collins SS, Swerczek TW. Continuance of studies on Population S benzimidazole-resistant small strongyles in a Shetland pony herd in Kentucky: effect of pyrantel pamoate (1992-1999).. Vet Parasitol 2001 Jan 20;94(4):247-56.
    pubmed: 11137272doi: 10.1016/s0304-4017(00)00382-4google scholar: lookup
  3. Drudge JH, Lyons ET, Swerczek TW, Tolliver SC. Cambendazole for strongyle control in a pony band: selection of a drug-resistant population of small strongyles and teratologic implications.. Am J Vet Res 1983 Jan;44(1):110-4.
    pubmed: 6824213
  4. Reinemeyer CR. Small strongyles. Recent advances.. Vet Clin North Am Equine Pract 1986 Aug;2(2):281-312.
    pubmed: 3527374doi: 10.1016/s0749-0739(17)30717-4google scholar: lookup
  5. Drudge JH, Lyons ET. Methods in the evaluation of antiparasitic drugs in the horse.. Am J Vet Res 1977 Oct;38(10):1581-6.
    pubmed: 337859
  6. Lyons ET, Tolliver SC, Drudge JH, Stamper S, Swerczek TW, Granstrom DE. Critical test evaluation (1977-1992) of drug efficacy against endoparasites featuring benzimidazole-resistant small strongyles (population S) in Shetland ponies.. Vet Parasitol 1996 Nov 1;66(1-2):67-73.
    pubmed: 8988557doi: 10.1016/s0304-4017(96)00997-1google scholar: lookup
  7. DIMOCK WW. The two-gram daily dose of phenothiazine for strongylosis of the horse.. Vet Med 1949 Mar;44(3):99-102.
    pubmed: 18114814
  8. Drudge JH, Lyons ET, Tolliver SC, Swerczek TW. Use of oxibendazole for control of cambendazole-resistant small strongyles in a band of ponies: a six-year study.. Am J Vet Res 1985 Dec;46(12):2507-11.
    pubmed: 4083584

Citations

This article has been cited 6 times.
  1. Sallé G, Canlet C, Cortet J, Koch C, Malsa J, Reigner F, Riou M, Perrot N, Blanchard A, Mach N. Integrative biology defines novel biomarkers of resistance to strongylid infection in horses. Sci Rep 2021 Jul 12;11(1):14278.
    doi: 10.1038/s41598-021-93468-2pubmed: 34253752google scholar: lookup
  2. Reed KJ, Kunz IGZ, Scare JA, Nielsen MK, Turk PJ, Coleman RJ, Coleman SJ. The pelvic flexure separates distinct microbial communities in the equine hindgut. Sci Rep 2021 Feb 22;11(1):4332.
    doi: 10.1038/s41598-021-83783-zpubmed: 33619300google scholar: lookup
  3. Bellaw JL, Nielsen MK. Meta-analysis of cyathostomin species-specific prevalence and relative abundance in domestic horses from 1975-2020: emphasis on geographical region and specimen collection method. Parasit Vectors 2020 Oct 12;13(1):509.
    doi: 10.1186/s13071-020-04396-5pubmed: 33046130google scholar: lookup
  4. Scare JA, Leathwick DM, Sauermann CW, Lyons ET, Steuer AE, Jones BA, Clark M, Nielsen MK. Dealing with double trouble: Combination deworming against double-drug resistant cyathostomins. Int J Parasitol Drugs Drug Resist 2020 Apr;12:28-34.
    doi: 10.1016/j.ijpddr.2019.12.002pubmed: 31883485google scholar: lookup
  5. Hodgkinson JE, Freeman KL, Lichtenfels JR, Palfreman S, Love S, Matthews JB. Identification of strongyle eggs from anthelmintic-treated horses using a PCR-ELISA based on intergenic DNA sequences. Parasitol Res 2005 Mar;95(4):287-92.
    doi: 10.1007/s00436-004-1289-zpubmed: 15682337google scholar: lookup
  6. Klass LG, Krücken J, Mbedi S, Sparmann S, Schenk T, Andreotti S, von Samson-Himmelstjerna G. Characterizing mixed strongyle infections in foals and broodmares using cytochrome c oxidase subunit I deep amplicon sequencing. Parasit Vectors 2026 Jan 3;19(1):65.
    doi: 10.1186/s13071-025-07192-1pubmed: 41484633google scholar: lookup
Subscribe to our newsletter
Join 99,357 horse owners like you who receive our email updates on horse health and nutrition.