FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / Parasit Vectors / Characterizing mixed strongyle infections in foals and brood...
Parasites & vectors2026; 19(1); 65; doi: 10.1186/s13071-025-07192-1

Characterizing mixed strongyle infections in foals and broodmares using cytochrome c oxidase subunit I deep amplicon sequencing.

Abstract: Mixed strongyle infections represent the most prevalent equine parasitosis and can result in life-threatening disease, especially in young horses. Species involvement and pathogenesis of this parasitosis are poorly understood, and data on foals and broodmares are notably lacking. Methods: In a longitudinal study undertaken in 2022 in Germany, individual faecal samples (n = 497) and metadata were collected for naturally infected foals and broodmares (n = 48) kept under conventional husbandry conditions. Nematode infections were detected coproscopically via the Mini-FLOTAC method. In a subset of strongyle egg-positive samples (n = 46), species were identified using cytochrome c oxidase subunit I deep amplicon sequencing. Species prevalence, richness, and alpha and beta diversity were compared between foals and mares. Results: Overall, 22.2% of the foal samples and 10.2% of the mare samples were strongyle egg positive (eggs per gram > 5). Parascaris spp. were only detected in foals (15.1%). Strongyloides westeri was detected in one foal sample. Strongyle egg detection increased in likelihood with each additional sample timepoint (OR = 1.42, P < 0.001) and with ascarid egg detection (OR = 6.49, P < 0.001), while last anthelmintic treatment with pyrantel decreased the odds of detecting eggs (OR = 0.12, P = 0.002). Deep amplicon sequencing detected 16 species of small strongyles but no large strongyle species. Cylicostephanus goldi, Cylicostephanus minutus operational taxonomic unit II and Cylicocyclus ashworthi were significantly more prevalent in mares (P < 0.05), while Cylicostephanus calicatus operational taxonomic unit II was more prevalent in foals (P < 0.01). Mares showed a significantly higher amplicon sequence-variant-based richness (Chao 1 index, P < 0.001) and diversity (inverse Simpson index, P < 0.01) than foals. Group (foals vs. mares) explained some of the variance in beta diversity, according to permutational multivariate ANOVA. Co-infection with Parascaris spp. did not affect strongyle community composition in the foals. Bray-Curtis and Jaccard distance (dissimilarity) plots showed separate clusters for mares and foals, with some overlap and a moderate model fit. Conclusions: Cytochrome oxidase-based characterization of mixed strongyle infections revealed strongyle community differences between broodmares and foals. Possible age associations were identified for four species of small strongyles, including two cryptic species. Low overall strongyle prevalence and egg-shedding intensity, non-random sampling and differences in anthelmintic treatment schemes limited the statistical power of this study.
© 2025. The Author(s).
Get Full Text
Publication Date: 2026-01-03 PubMed ID: 41484633PubMed Central: PMC12866475DOI: 10.1186/s13071-025-07192-1Google 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.

Overview

  • This study investigated the types and diversity of strongyle parasite infections in foals and broodmares using advanced DNA sequencing methods on fecal samples.
  • It identified differences in parasite species composition and diversity between young horses (foals) and adult females (mares), improving understanding of equine parasitic infections.

Background

  • Strongyles are parasitic nematodes commonly infecting horses and can cause serious health issues, especially in young horses.
  • Understanding which specific strongyle species infect horses and how their communities differ by age is important but previously limited.
  • The study focuses on foals and broodmares under conventional horse-keeping conditions in Germany, aiming to fill knowledge gaps.

Methods

  • Collected 497 individual fecal samples from 48 horses (foals and broodmares) in 2022.
  • Used the Mini-FLOTAC method, a microscopic technique, to detect nematode eggs in feces.
  • Selected 46 samples positive for strongyle eggs for further analysis using cytochrome c oxidase subunit I (COI) deep amplicon sequencing, a DNA-based method enabling precise identification of parasite species.
  • Analyzed species prevalence, richness (number of species), and diversity within (alpha diversity) and between (beta diversity) horse groups.

Key Results

  • Prevalence of infection: 22.2% of foal samples and 10.2% of mare samples had detectable strongyle eggs.
  • Other parasites: Parascaris species eggs found only in foals (15.1%); Strongyloides westeri detected in one foal.
  • Likelihood of strongyle egg detection increased with multiple sampling times and presence of ascarid eggs, but decreased following treatment with the anthelmintic pyrantel.
  • Species diversity: Identified 16 small strongyle species; no large strongyle species detected.
  • Some species were more prevalent in mares (e.g., Cylicostephanus goldi, Cylicostephanus minutus OTU II, Cylicocyclus ashworthi), while Cylicostephanus calicatus OTU II was more common in foals.
  • Mares had significantly higher parasite species richness and diversity compared to foals, suggesting differences in infection complexity with age.
  • Statistical analyses showed group membership (foals vs. mares) partially explained differences in parasite community composition.
  • Presence of Parascaris spp. co-infection did not significantly alter strongyle community structure in foals.

Interpretation

  • DNA sequencing of the COI gene effectively characterized mixed strongyle infections, revealing species-specific and age-related infection patterns.
  • Higher diversity in mares likely results from longer exposure and accumulation of multiple strongyle species.
  • Age-related differences in prevalence of certain small strongyle species suggest possible species-specific host preferences or immune interactions.
  • Lack of large strongyle species may reflect current management or anthelmintic practices reducing these historically important parasites.

Limitations

  • Low overall prevalence and intensity of strongyle egg shedding limited the amount of data available for robust statistical conclusions.
  • Sampling was not random and differences in timing and types of anthelmintic treatments between foals and mares may have influenced results.
  • Study focused on a single geographic region and limited number of horses, requiring broader studies to confirm findings.

Conclusions and Implications

  • The study advances knowledge about the composition and diversity of strongyle infections in horses, highlighting differences between young and adult animals.
  • Identification of cryptic and age-associated species suggests the need for tailored parasite control strategies.
  • Deep amplicon sequencing is a valuable tool for detailed parasite community profiling in equine health research and management.

Cite This Article

APA
Klass LG, Krücken J, Mbedi S, Sparmann S, Schenk T, Andreotti S, von Samson-Himmelstjerna G. (2026). Characterizing mixed strongyle infections in foals and broodmares using cytochrome c oxidase subunit I deep amplicon sequencing. Parasit Vectors, 19(1), 65. https://doi.org/10.1186/s13071-025-07192-1

Publication

Parasites & vectors
ISSN: 1756-3305
NlmUniqueID: 101462774
Country: England
Language: English
Volume: 19
Issue: 1
Pages: 65
PII: 65

Researcher Affiliations

Klass, Luise Grace
  • Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
  • Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany.
  • Institute of Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany.
Krücken, Jürgen
  • Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
  • Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany.
Mbedi, Susan
  • Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany.
  • Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.
Sparmann, Sarah
  • Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany.
  • Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
Schenk, Thore
  • Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
  • Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany.
Andreotti, Sandro
  • Bioinformatics Solutions Center, Institute of Computer Science, Freie Universität Berlin, Berlin, Germany.
von Samson-Himmelstjerna, Georg
  • Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany. samson.georg@fu-berlin.de.
  • Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany. samson.georg@fu-berlin.de.

MeSH Terms

  • Animals
  • Horses
  • Electron Transport Complex IV / genetics
  • Feces / parasitology
  • Germany / epidemiology
  • Strongyle Infections, Equine / parasitology
  • Strongyle Infections, Equine / epidemiology
  • Female
  • Longitudinal Studies
  • Horse Diseases / parasitology
  • Horse Diseases / epidemiology
  • High-Throughput Nucleotide Sequencing
  • Prevalence
  • Coinfection / veterinary
  • Coinfection / parasitology
  • Coinfection / epidemiology
  • Parasite Egg Count
  • Male

Grant Funding

  • 033W034A / German Federal Ministry of Education and Research (BMBF)
  • RTG 2046, 251133687 / Deutsche Forschungsgemeinschaft

Conflict of Interest Statement

Declarations. Ethics approval and consent to participate: In accordance with established guidelines, ethical approval was not required for this study, as the research exclusively used environmental samples. All of the owners voluntarily allowed participation of their animals in this study, were informed about all of the procedures and further processing of the collected data, and gave their consent for the data to be published. Competing interests: GvSH declares that he has worked repeatedly as a consultant for different veterinary pharmaceutical and diagnostic companies. He currently has several ongoing research collaborations with various companies. All of the other authors declare that they have no competing interests.

References

This article includes 89 references
  1. Bredtmann CM, Krücken J, Murugaiyan J, Kuzmina T, Von Samson-Himmelstjerna G. Nematode species identification—current status, challenges and future perspectives for cyathostomins.. Front Cell Infect Microbiol 2017;7:283.
    doi: 10.3389/fcimb.2017.00283pmc: PMC5487379pubmed: 28702376google scholar: lookup
  2. Nielsen MK, Branan MA, Wiedenheft AM, Digianantonio R, Scare JA, Bellaw JL. Risk factors associated with strongylid egg count prevalence and abundance in the United States equine population.. Vet Parasitol 2018;257:58–68.
    doi: 10.1016/j.vetpar.2018.05.006pubmed: 29773232google 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;13:509.
    doi: 10.1186/s13071-020-04396-5pmc: PMC7552500pubmed: 33046130google scholar: lookup
  4. Sallé G, Guillot J, Tapprest J, Foucher N, Sevin C, Laugier C. Compilation of 29 years of postmortem examinations identifies major shifts in equine parasite prevalence from 2000 onwards.. Int J Parasitol 2020;50:125–32.
    doi: 10.1016/j.ijpara.2019.11.004pubmed: 31981673google scholar: lookup
  5. Abbas G, Ghafar A, Bauquier J, Beasley A, Ling E, Gauci CG. Prevalence and diversity of ascarid and strongylid nematodes in Australian thoroughbred horses using next-generation sequencing and bioinformatic tools.. Vet Parasitol 2023;323:110048.
    doi: 10.1016/j.vetpar.2023.110048pubmed: 37844388google scholar: lookup
  6. Love S, Murphy D, Mellor D. Pathogenicity of cyathostome infection.. Vet Parasitol 1999;85:113–22.
    doi: 10.1016/S0304-4017(99)00092-8pubmed: 10485358google scholar: lookup
  7. Mair TS, Sutton DGM, Love S. Caecocaecal and caecocolic intussusceptions associated with larval cyathostomosis in four young horses.. Equine Vet J 2000;32:77–80.
    doi: 10.1111/j.2042-3306.2000.tb05339.xpubmed: 11202389google scholar: lookup
  8. Peachey LE, Castro C, Molena RA, Jenkins TP, Griffin JL, Cantacessi C. Dysbiosis associated with acute helminth infections in herbivorous youngstock—observations and implications.. Sci Rep 2019;9:11121.
    doi: 10.1038/s41598-019-47204-6pmc: PMC6668452pubmed: 31366962google scholar: lookup
  9. Peregrine AS, McEwen B, Bienzle D, Koch TG, Weese JS. Larval cyathostominosis in horses in Ontario: an emerging disease?. Can Vet J Rev Vet Can 2006;47:80–2.
    pmc: PMC1316126pubmed: 16536234
  10. Lichtenfels JR, Kharchenko VA, Dvojnos GM. Illustrated identification keys to strongylid parasites (strongylidae: Nematoda) of horses, zebras and asses (Equidae).. Vet Parasitol 2008;156:4–161.
    doi: 10.1016/j.vetpar.2008.04.026pubmed: 18603375google scholar: lookup
  11. Lyons ET, Kuzmina TA, Tolliver SC, Collins SS. Observations on development of natural infection and species composition of small strongyles in young equids in Kentucky.. Parasitol Res 2011;109:1529–35.
    doi: 10.1007/s00436-011-2460-ypubmed: 21614543google scholar: lookup
  12. Bellaw JL, Krebs K, Reinemeyer CR, Norris JK, Scare JA, Pagano S. Anthelmintic therapy of equine cyathostomin nematodes—larvicidal efficacy, egg reappearance period, and drug resistance.. Int J Parasitol 2018;48:97–105.
    doi: 10.1016/j.ijpara.2017.08.009pubmed: 29050919google scholar: lookup
  13. Bredtmann CM, Krücken J, Kuzmina T, Louro M, Madeira De Carvalho LM, Von Samson-Himmelstjerna G. Nuclear and mitochondrial marker sequences reveal close relationship between and a potential cryptic species complex.. Infect Genet Evol 2019;75:103956.
    doi: 10.1016/j.meegid.2019.103956pubmed: 31299325google scholar: lookup
  14. Kooyman FNJ, Van Doorn DCK, Geurden T, Mughini-Gras L, Ploeger HW, Wagenaar JA. Species composition of larvae cultured after anthelmintic treatment indicates reduced moxidectin susceptibility of immature species in horses.. Vet Parasitol 2016;227:77–84.
    doi: 10.1016/j.vetpar.2016.07.029pubmed: 27523942google scholar: lookup
  15. Van Doorn DCK, Ploeger HW, Eysker M, Geurden T, Wagenaar JA, Kooyman FNJ. species predominate during shortened egg reappearance period in horses after treatment with ivermectin and moxidectin.. Vet Parasitol 2014;206:246–52.
    doi: 10.1016/j.vetpar.2014.10.004pubmed: 25458565google scholar: lookup
  16. 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;66:67–73.
    doi: 10.1016/S0304-4017(96)00997-1pubmed: 8988557google scholar: lookup
  17. Drudge JH, Tolliver SC, Lyons ΕT. Benzimidazole resistance of equine strongyles: critical tests of several classes of compounds against population B strongyles from 1977 to 1981.. Am J Vet Res 1984;45:804–9.
    doi: 10.2460/ajvr.1984.45.04.804pubmed: 6731997google scholar: lookup
  18. Hedberg Alm Y, Halvarsson P, Martin F, Osterman-Lind E, Törngren V, Tydén E. Demonstration of reduced efficacy against cyathostomins without change in species composition after pyrantel embonate treatment in Swedish equine establishments.. Int J Parasitol Drugs Drug Resist 2023;23:78–86.
    doi: 10.1016/j.ijpddr.2023.11.003pmc: PMC10690405pubmed: 37979235google scholar: lookup
  19. 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;94:247–56.
    doi: 10.1016/S0304-4017(00)00382-4pubmed: 11137272google scholar: lookup
  20. Bull KE, Allen KJ, Hodgkinson JE, Peachey LE. The first report of macrocyclic lactone resistant cyathostomins in the UK.. Int J Parasitol Drugs Drug Resist 2023;21:125–30.
    doi: 10.1016/j.ijpddr.2023.03.001pmc: PMC10036890pubmed: 36940551google scholar: lookup
  21. Dauparaitė E, Kupčinskas T, Von Samson-Himmelstjerna G, Petkevičius S. Anthelmintic resistance of horse strongyle nematodes to ivermectin and pyrantel in Lithuania.. Acta Vet Scand 2021;63:5.
    doi: 10.1186/s13028-021-00569-zpmc: PMC7836172pubmed: 33494770google scholar: lookup
  22. Nielsen MK, Steuer AE, Anderson HP, Gavriliuc S, Carpenter AB, Redman EM. Shortened egg reappearance periods of equine cyathostomins following ivermectin or moxidectin treatment: morphological and molecular investigation of efficacy and species composition.. Int J Parasitol 2022;52:787–98.
    doi: 10.1016/j.ijpara.2022.09.003pubmed: 36244428google scholar: lookup
  23. Lyons E. 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 2003;91:407–11.
    doi: 10.1007/s00436-003-0983-6pubmed: 14530968google scholar: lookup
  24. Boisseau M, Mach N, Basiaga M, Kuzmina T, Laugier C, Sallé G. Patterns of variation in equine strongyle community structure across age groups and gut compartments.. Parasit Vectors 2023;16:64.
    doi: 10.1186/s13071-022-05645-5pmc: PMC9921056pubmed: 36765420google scholar: lookup
  25. Kuzmina TA, Dzeverin I, Kharchenko VA. Strongylids in domestic horses: influence of horse age, breed and deworming programs on the strongyle parasite community.. Vet Parasitol 2016;227:56–63.
    doi: 10.1016/j.vetpar.2016.07.024pubmed: 27523938google scholar: lookup
  26. Lester HE, Morgan ER, Hodgkinson JE, Matthews JB. Analysis of strongyle egg shedding consistency in horses and factors that affect it.. J Equine Vet Sci 2018;60:113-119.e1.
    doi: 10.1016/j.jevs.2017.04.006google scholar: lookup
  27. Sallé G, Kornaś S, Basiaga M. Equine strongyle communities are constrained by horse sex and species dipersal-fecundity trade-off.. Parasit Vectors 2018;11:279.
    doi: 10.1186/s13071-018-2858-9pmc: PMC5930759pubmed: 29716644google scholar: lookup
  28. Boelow H, Krücken J, Von Samson-Himmelstjerna G. Epidemiological study on factors influencing the occurrence of helminth eggs in horses in Germany based on sent-in diagnostic samples.. Parasitol Res 2023;122:749–67.
    doi: 10.1007/s00436-022-07765-4pmc: PMC9988789pubmed: 36627515google scholar: lookup
  29. Nielsen MK, Gee EK, Hansen A, Waghorn T, Bell J, Leathwick DM. Monitoring equine ascarid and cyathostomin parasites: evaluating health parameters under different treatment regimens.. Equine Vet J 2021;53:902–10.
    doi: 10.1111/evj.13374pubmed: 33119179google scholar: lookup
  30. Tydén E, Jansson A, Ringmark S. Parasites in horses kept in a 2.5 year-round grazing system in Nordic conditions without supplementary feeding.. Animals 2019;9:1156.
    doi: 10.3390/ani9121156pmc: PMC6940839pubmed: 31861066google scholar: lookup
  31. Wood ELD, Matthews JB, Stephenson S, Slote M, Nussey DH. Variation in fecal egg counts in horses managed for conservation purposes: individual egg shedding consistency, age effects and seasonal variation.. Parasitology 2013;140:115–28.
    doi: 10.1017/S003118201200128Xpubmed: 22894917google scholar: lookup
  32. Gasser RB, Hung G-C, Chilton NB, Beveridge I. Advances in developing molecular-diagnostic tools for strongyloid nematodes of equids: fundamental and applied implications.. Mol Cell Probes 2004;18:3–16.
    doi: 10.1016/j.mcp.2003.10.001pubmed: 15036364google scholar: lookup
  33. Nielsen MK, Von Samson-Himmelstjerna G, Kuzmina TA, Van Doorn DCK, Meana A, Rehbein S. World association for the advancement of veterinary parasitology (WAAVP): third edition of guideline for evaluating the efficacy of equine anthelmintics.. Vet Parasitol 2022;303:109676.
    doi: 10.1016/j.vetpar.2022.109676pubmed: 35164972google scholar: lookup
  34. Daş G, Klauser S, Stehr M, Tuchscherer A, Metges CC. Accuracy and precision of McMaster and Mini-FLOTAC egg counting techniques using egg-spiked faeces of chickens and two different flotation fluids.. Vet Parasitol 2020;283:109158.
    doi: 10.1016/j.vetpar.2020.109158pubmed: 32544762google scholar: lookup
  35. Mohammedsalih KM, Hassan SA, Juma F-R, Saeed SI, Bashar A, von Samson-Himmelstjerna G. Comparative assessment of Mini-FLOTAC, McMaster and semi-quantitative flotation for helminth egg examination in camel faeces.. Parasit Vectors 2025;18:5.
    doi: 10.1186/s13071-024-06637-3pmc: PMC11726973pubmed: 39800725google scholar: lookup
  36. Barda B, Cajal P, Villagran E, Cimino R, Juarez M, Krolewiecki A. Mini-FLOTAC, Kato-Katz and McMaster: three methods, one goal; highlights from north Argentina.. Parasit Vectors 2014;7:271.
    doi: 10.1186/1756-3305-7-271pmc: PMC4074144pubmed: 24929554google scholar: lookup
  37. Cringoli G, Maurelli MP, Levecke B, Bosco A, Vercruysse J, Utzinger J. The Mini-FLOTAC technique for the diagnosis of helminth and protozoan infections in humans and animals.. Nat Protoc 2017;12:1723–32.
    doi: 10.1038/nprot.2017.067pubmed: 28771238google scholar: lookup
  38. Jürgenschellert L, Krücken J, Austin CJ, Lightbody KL, Bousquet E, Von Samson-Himmelstjerna G. Investigations on the occurrence of tapeworm infections in German horse populations with comparison of different antibody detection methods based on saliva and serum samples.. Parasit Vectors 2020;13:462.
    doi: 10.1186/s13071-020-04318-5pmc: PMC7488081pubmed: 32912340google scholar: lookup
  39. Lejeune M, Mann S, White H, Maguire D, Hazard J, Young R. Evaluation of fecal egg count tests for effective control of equine intestinal strongyles.. Pathogens 2023;12:1283.
    doi: 10.3390/pathogens12111283pmc: PMC10674696pubmed: 38003748google scholar: lookup
  40. Courtot É, Boisseau M, Dhorne-Pollet S, Serreau D, Gesbert A, Reigner F. Comparison of two molecular barcodes for the study of equine strongylid communities with amplicon sequencing.. PeerJ 2023;11:e15124.
    doi: 10.7717/peerj.15124pmc: PMC10105562pubmed: 37070089google scholar: lookup
  41. Ghafar A, Abbas G, Beasley A, Bauquier J, Wilkes EJA, Jacobson C. Molecular diagnostics for gastrointestinal helminths in equids: past, present and future.. Vet Parasitol 2023;313:109851.
    doi: 10.1016/j.vetpar.2022.109851pubmed: 36521296google scholar: lookup
  42. Krücken J, Diekmann I, Andreotti S, Bredtmann CM, Mbedi S, Sparmann S. Cytochrome c oxidase I deep amplicon sequencing for metabarcoding of equine strongyle communities: unexpectedly high Strongylus spp. burden in treated horses.. bioRxiv 2025;:2025.05.12.653446.
    pubmed: 41052572doi: 10.1101/2025.05.12.653446google scholar: lookup
  43. Diekmann I, Krücken J, Kuzmina TA, Bredtmann CM, Louro M, Kharchenko VA. Comparative phylogenetic and sequence identity analysis of internal transcribed spacer 2 and cytochrome c oxidase subunit I as DNA barcode markers for the most common equine Strongylidae species.. Infect Genet Evol 2025;129:105729.
    doi: 10.1016/j.meegid.2025.105729pubmed: 39955017google scholar: lookup
  44. Byrne O, Gangotia D, Crowley J, Zintl A, Kiser L, Boxall O. Molecular species determination of cyathostomins from horses in Ireland.. Vet Parasitol 2024;328:110168.
    doi: 10.1016/j.vetpar.2024.110168pubmed: 38547830google scholar: lookup
  45. Mitchell MC, Tzelos T, Handel I, Mcwilliam HEG, Hodgkinson JE, Nisbet AJ. Development of a recombinant protein-based ELISA for diagnosis of larval cyathostomin infection.. Parasitology 2016;143:1055–66.
    doi: 10.1017/S0031182016000627pubmed: 27174468google scholar: lookup
  46. Poissant J, Gavriliuc S, Bellaw J, Redman EM, Avramenko RW, Robinson D. A repeatable and quantitative DNA metabarcoding assay to characterize mixed strongyle infections in horses.. Int J Parasitol 2021;51:183–92.
    doi: 10.1016/j.ijpara.2020.09.003pubmed: 33242465google scholar: lookup
  47. Sargison N, Chambers A, Chaudhry U, Costa Júnior L, Doyle SR, Ehimiyein A. Faecal egg counts and nemabiome metabarcoding highlight the genomic complexity of equine cyathostomin communities and provide insight into their dynamics in a Scottish native pony herd.. Int J Parasitol 2022;52:763–74.
    doi: 10.1016/j.ijpara.2022.08.002pubmed: 36208676google scholar: lookup
  48. Diekmann I, Blazejak K, Krücken J, Strube C, von Samson-Himmelstjerna G. Comparison of morphological and molecular spp. identification in equine larval cultures and first report of a patent infection in a horse.. Equine Vet J 2025;57:522–9.
    doi: 10.1111/evj.14134pmc: PMC11807925pubmed: 39012065google scholar: lookup
  49. Louro M, Kuzmina TA, Bredtmann CM, Diekmann I, De Carvalho LMM, Von Samson-Himmelstjerna G. Genetic variability, cryptic species and phylogenetic relationship of six cyathostomin species based on mitochondrial and nuclear sequences.. Sci Rep 2021;11:8245.
    doi: 10.1038/s41598-021-87500-8pmc: PMC8050097pubmed: 33859247google scholar: lookup
  50. Cringoli G, Rinaldi L, Maurelli MP, Utzinger J. FLOTAC: new multivalent techniques for qualitative and quantitative copromicroscopic diagnosis of parasites in animals and humans.. Nat Protoc 2010;5:503–15.
    doi: 10.1038/nprot.2009.235pubmed: 20203667google scholar: lookup
  51. Demeler J, Ramünke S, Wolken S, Ianiello D, Rinaldi L, Gahutu JB. Discrimination of gastrointestinal nematode eggs from crude fecal egg preparations by inhibitor-resistant conventional and real-time PCR.. PLoS ONE 2013;8:e61285.
    doi: 10.1371/journal.pone.0061285pmc: PMC3631180pubmed: 23620739google scholar: lookup
  52. Krücken J, Diekmann I, Andreotti S, Bredtmann CM, Mbedi S, Sparmann S. Cytochrome c oxidase I deep amplicon sequencing for metabarcoding of equine strongyle communities: unexpectedly high spp. prevalence in treated horses.. Int J Parasitol 2025;:S0020751925001821.
    pubmed: 41052572doi: 10.1016/j.ijpara.2025.09.007google scholar: lookup
  53. Duscher GG, Harl J, Fuehrer H-P. Evidence of and sp. coinfection in a polecat from Lower Austria.. Helminthologia 2015;52:63–6.
    doi: 10.1515/helmin-2015-0011google scholar: lookup
  54. Berensmeier S. Magnetic particles for the separation and purification of nucleic acids.. Appl Microbiol Biotechnol 2006;73:495–504.
    doi: 10.1007/s00253-006-0675-0pmc: PMC7080036pubmed: 17063328google scholar: lookup
  55. Klass LG, Diekmann I, Andreotti S, Mbedi S, Sparmann S, Schenk T. Species diversity and within-host tropism for mixed equine strongyle infections using a cytochrome c oxidase subunit I metabarcoding approach.. Int J Parasitol 2025;S0020–7519:00185–7.
    doi: 10.1016/j.ijpara.2025.09.010pubmed: 41072705google scholar: lookup
  56. Martin M. Cutadapt removes adapter sequences from high-throughput sequencing reads.. EMBnetjournal 2011;17:10.
    doi: 10.14806/ej.17.1.200google scholar: lookup
  57. Callahan BJ, McMurdie PJ, Rosen MJ, Han AW, Johnson AJA, Holmes SP. DADA2: high-resolution sample inference from Illumina amplicon data.. Nat Methods 2016;13:581–3.
    doi: 10.1038/nmeth.3869pmc: PMC4927377pubmed: 27214047google scholar: lookup
  58. Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ. Basic Local Alignment Search Tool.. J Mol Biol 1990;215:403–10.
    doi: 10.1016/S0022-2836(05)80360-2pubmed: 2231712google scholar: lookup
  59. . R a language and environment for statistical computing: reference index.. Vienna: R Foundation for Statistical Computing; 2010.
  60. Bates D, Maechler M, Bolker B, Walker S. lme4: linear mixed-effects models using “Eigen” and S4.. 2003;1:1–37.
    doi: 10.32614/cran.package.lme4google scholar: lookup
  61. Brooks ME, Kristensen K, Benthem KJ, van Magnusson A, Berg CW, Nielsen A. glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling.. R J 2017;9:378.
    doi: 10.32614/rj-2017-066google scholar: lookup
  62. Kuhn M, Jackson S, Cimentada J. corrr: Correlations in R.. 2016;:0.4.4.
    doi: 10.32614/cran.package.corrrgoogle scholar: lookup
  63. Hartig F. DHARMa: residual diagnostics for hierarchical (multi-level/mixed) regression models.. 2016;:0.4.7.
    doi: 10.32614/cran.package.dharmagoogle scholar: lookup
  64. Oksanen J, Simpson GL, Blanchet FG, Kindt R, Legendre P, Minchin PR. vegan: community ecology package.. 2001;2.6–10.
    doi: 10.32614/cran.package.vegangoogle scholar: lookup
  65. . Annual precipitation report for Germany.. 2022.
  66. Kuzmina TA, Kharchenko VO. Anthelmintic resistance in cyathostomins of brood horses in Ukraine and influence of anthelmintic treatments on strongylid community structure. Vet Parasitol 2008;154:277–88.
    doi: 10.1016/j.vetpar.2008.03.024pubmed: 18485600google scholar: lookup
  67. Lyons ET, Tolliver SC, Kuzmina TA. Investigation of strongyle EPG values in horse mares relative to known age, number positive, and level of egg shedding in field studies on 26 farms in central Kentucky (2010–2011). Parasitol Res 2012;110:2237–45.
    doi: 10.1007/s00436-011-2755-zpubmed: 22167377google scholar: lookup
  68. Čerňanská D, Paoletti B, Kráľová-Hromadová I, Iorio R, Čudeková P, Milillo P. Application of a reverse line blot hybridisation assay for the species-specific identification of cyathostomins (Nematoda, Strongylida) from benzimidazole-treated horses in the Slovak Republic. Vet Parasitol 2009;160:171–4.
    doi: 10.1016/j.vetpar.2008.10.078pubmed: 19042091google scholar: lookup
  69. Chapman MR, Klei TR, French DD. Identification of thiabendazole-resistant cyathostome species in Louisiana. Vet Parasitol 1991;39:293–9.
    doi: 10.1016/0304-4017(91)90046-Xpubmed: 1957489google scholar: lookup
  70. 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;95:287–92.
    doi: 10.1007/s00436-004-1289-zpubmed: 15682337google scholar: lookup
  71. Traversa D, von Samson-Himmelstjerna G, Demeler J, Milillo P, Schürmann S, Barnes H. Anthelmintic resistance in cyathostomin populations from horse yards in Italy, United Kingdom and Germany. Parasit Vectors 2009;2:S2.
    doi: 10.1186/1756-3305-2-S2-S2pmc: PMC2751838pubmed: 19778463google scholar: lookup
  72. Merlin A, Larcher N, Vallé-Casuso J-C. The first report of triple anthelmintic resistance on a French thoroughbred stud farm. Int J Parasitol Drugs Drug Resist 2024;24:100528.
    doi: 10.1016/j.ijpddr.2024.100528pmc: PMC10910056pubmed: 38422764google scholar: lookup
  73. Bull KE, Hodgkinson J, Allen K, Poissant J, Peachey LE. Quantitative DNA metabarcoding reveals species composition of a macrocyclic lactone and pyrantel resistant cyathostomin population in the UK. Int J Parasitol Drugs Drug Resist 2025;27:100576.
    doi: 10.1016/j.ijpddr.2024.100576pmc: PMC11762968pubmed: 39778419google scholar: lookup
  74. Abbas G, Ghafar A, Hurley J, Bauquier J, Beasley A, Wilkes EJA. Cyathostomin resistance to moxidectin and combinations of anthelmintics in Australian horses. Parasit Vectors 2021;14:597.
    doi: 10.1186/s13071-021-05103-8pmc: PMC8645149pubmed: 34863271google scholar: lookup
  75. Nielsen MK, Banahan M, Kaplan RM. Importation of macrocyclic lactone resistant cyathostomins on a US thoroughbred farm. Int J Parasitol Drugs Drug Resist 2020;14:99–104.
    doi: 10.1016/j.ijpddr.2020.09.004pmc: PMC7548974pubmed: 33022574google scholar: lookup
  76. Russell AF. The development of helminthiasis in thoroughbred foals. J Comp Pathol Ther 1948;58:107–27.
    doi: 10.1016/S0368-1742(48)80009-3pubmed: 18861669google scholar: lookup
  77. Nielsen MK, Lyons ET. Encysted cyathostomin larvae in foals—progression of stages and the effect of seasonality. Vet Parasitol 2017;236:108–12.
    doi: 10.1016/j.vetpar.2017.02.013pubmed: 28288752google scholar: lookup
  78. Steuer AE, Anderson HP, Shepherd T, Clark M, Scare JA, Gravatte HS. Parasite dynamics in untreated horses through one calendar year. Parasit Vectors 2022;15:50.
    doi: 10.1186/s13071-022-05168-zpmc: PMC8822790pubmed: 35135605google scholar: lookup
  79. Collobert-Laugier C, Hoste H, Sevin C, Dorchies P. Prevalence, abundance and site distribution of equine small strongyles in Normandy, France. Vet Parasitol 2002;110:77–83.
    doi: 10.1016/S0304-4017(02)00328-Xpubmed: 12446091google scholar: lookup
  80. Johnson ACB, Biddle AS. The use of molecular profiling to track equine reinfection rates of cyathostomin species following anthelmintic administration. Animals 2021;11:1345.
    doi: 10.3390/ani11051345pmc: PMC8150961pubmed: 34065099google scholar: lookup
  81. Hung G-C, Chilton NB, Beveridge I, Zhu XQ, Lichtenfels JR, Gasser RB. Molecular evidence for cryptic species within (Nematoda: Strongylidae)fn1fn1 Note: Nucleotide sequence data reported in this paper are available in the embl, GenBankTM and DDBJ databases under the accession numbers AJ228241, AJ005831, AJ228239, AJ228240, aj 004843, AJ005832, AJ004841 and AJ004842. Int J Parasitol 1999;29:285–91.
    doi: 10.1016/S0020-7519(98)00203-3pubmed: 10221629google scholar: lookup
  82. Kamiya T, O’Dwyer K, Nakagawa S, Poulin R. What determines species richness of parasitic organisms? A meta-analysis across animal, plant and fungal hosts. Biol Rev Camb Philos Soc 2014;89:123–34.
    doi: 10.1111/brv.12046pubmed: 23782597google scholar: lookup
  83. Råberg L, Graham AL, Read AF. Decomposing health: tolerance and resistance to parasites in animals. Philos Trans R Soc Lond B Biol Sci 2009;364:37–49.
    doi: 10.1098/rstb.2008.0184pmc: PMC2666700pubmed: 18926971google scholar: lookup
  84. Klei TR. Equine immunity to parasites. Vet Clin North Am Equine Pract 2000;16:vi.
    doi: 10.1016/s0749-0739(17)30119-0pubmed: 10752139google scholar: lookup
  85. Klei TR, Chapman MR. Immunity in equine cyathostome infections. Vet Parasitol 1999;85:123–36.
    doi: 10.1016/S0304-4017(99)00093-Xpubmed: 10485359google scholar: lookup
  86. Adams AA, Betancourt A, Barker VD, Siard MH, Elzinga S, Bellaw JL. Comparison of the immunologic response to anthelmintic treatment in old versus middle-aged horses. J Equine Vet Sci 2015;35:873-881.e3.
    doi: 10.1016/j.jevs.2015.07.005google scholar: lookup
  87. Harvey AM, Meggiolaro MN, Hall E, Watts ET, Ramp D, Šlapeta J. Wild horse populations in south-east Australia have a high prevalence of and may act as a reservoir of infection for domestic horses. Int J Parasitol Parasites Wildl 2019;8:156–63.
    doi: 10.1016/j.ijppaw.2019.01.008pmc: PMC6378629pubmed: 30815358google scholar: lookup
  88. 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 in Alberta feral horses. Int J Parasitol Parasites Wildl 2025;27:101091.
    doi: 10.1016/j.ijppaw.2025.101091pmc: PMC12167826pubmed: 40524829google scholar: lookup
  89. Zvegintsova NS, Zharkikh TL, Joint Directorate of State Nature Reserves «Orenburg» and «Shaitan-Tau», Kuzmina TA, I.I. Schmalhausen Institute of Zoology NAS of Ukraine. Parasites of Przewalski’s horses (Equus Ferus Przewalskii) in Askania nova biosphere reserve (Ukraine) and Orenburg State Nature Reserve (Russia). Nat Conserv Res 2019;4 Suppl.2.
    doi: 10.24189/ncr.2019.030google scholar: lookup

Citations

This article has been cited 0 times.
Subscribe to our newsletter
Join 99,000 horse owners like you who receive our email updates on horse health and nutrition.