Physiologic and systemic acute phase inflammatory responses in young horses repeatedly infected with cyathostomins and Strongylus vulgaris

U. V. Andersen, C. R. Reinemeyer, N. Toft, S. N. Olsen, S. Jacobsen, M. K. Nielsen

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Migrating Strongylus vulgaris and encysted cyathostomin larvae cause a localized inflammatory response in horses. It is unknown whether these larvae elicit a systemic acute phase response (APR), evidenced by changes in serum amyloid A (SAA), haptoglobin (Hp), iron (Fe), albumin, or albumin/globulin (A/G) ratio. In this study, 28 horses were randomly allocated to receive either pyrantel tartrate or a pelleted placebo formulation in their daily feed. Concurrent with treatment, all the horses were administered 5000 pyrantel-susceptible cyathostomin infective larvae once daily, 5 days a week, for 24 weeks. Beginning in the fifth week, the horses also received 25 S. vulgaris larvae once weekly for the remainder of the study. At regular biweekly intervals, fecal samples were collected for quantitative egg counts, and whole blood and serum samples were collected for measurement of packed cell volume, total protein, albumin, globulin, A/G ratio, SAA, Hp, and Fe. On days 161-164, all the horses were euthanatized and necropsied. Samples were collected for enumeration of total luminal worm burdens, encysted cyathostomin larval populations, and migrating S. vulgaris larvae. Concentrations of Hp, Fe, and A/G ratio were associated significantly with strongyle burdens. Only treated male horses had significant increases in serum albumin. Larval S. vulgaris did not associate with Fe, whereas Fe was associated negatively with both total cyathostomin burdens and encysted L4s. The A/G ratios differed significantly between the two treatment groups. Significant differences between groups and individual time points were also observed for Hp and Fe, whereas SAA concentrations remained low throughout the study. In general, this study illustrated that experimental inoculations with S. vulgaris and cyathostomins may be associated with changes in Hp, Fe, and serum proteins, but not with SAA. Overall, these changes suggest that mixed strongyle infections elicit a mild acute phase reaction.

Original languageEnglish
Pages (from-to)67-74
Number of pages8
JournalVeterinary Parasitology
Issue number1-2
StatePublished - 2014

Bibliographical note

Funding Information:
The authors gratefully thank the sponsor of the study, Farnam Companies, Inc., for providing us with serum samples, PCV, serum protein measurements, and parasitological data for this study. The Horse Levy Fund of Denmark is acknowledged for financial support of the analysis of acute-phase markers.


  • Acute phase response
  • Cyathostomins
  • Haptoglobin
  • Iron
  • Serum amyloid A
  • Strongylus vulgaris

ASJC Scopus subject areas

  • Parasitology
  • General Veterinary


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