Comparison of the host response to larvicidal and nonlarvicidal treatment of naturally acquired cyathostomin infections in horses

Ashley E. Steuer, Kirsten Scoggin, John C. Stewart, Virginia D. Barker, Amanda A. Adams, Alan T. Loynachan, Martin K. Nielsen

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


This study aimed to collect information on local and systemic inflammatory responses, and goblet cell-associated components, following anthelmintic treatment with moxidectin and ivermectin in horses naturally infected with cyathostomin parasites. Thirty-six horses aged 2–5 years of age were randomly allocated to three groups. Group 1 received ivermectin/praziquantel (0.2 mg/kg), Group 2 received moxidectin/praziquantel (0.4 mg/kg) and Group 3 were untreated controls. Tissue samples from the Cecum, Dorsal and Ventral Colons were used for histopathological evaluation and preserved for RNA isolation and gene expression analysis. Whole blood was collected weekly for gene expression analysis as well. The control group had significantly higher inflammation associated with higher larval scores. The treatment groups displayed no differences in larval counts and inflammatory cell populations (p >.05). Mucosal larval counts were positively correlated with goblet cell hyperplasia scores (p =.047). The moxidectin-treated group had a significantly lower expression of IFN-γ (p <.05). The data suggest that removal of cyathostomins reduced the pro-inflammatory response associated with cyathostomin infections. Pro-inflammatory reactions associated with anthelmintic treatment were minimal, but lowest for moxidectin-treated horses. Results suggested that cecum, ventral and dorsal colons responded differently to cyathostomin larvae, which may have implications in the disease process.

Original languageEnglish
Article numbere12941
JournalParasite Immunology
Issue number10
StatePublished - Oct 2022

Bibliographical note

Funding Information:
The authors would like to thank Zoetis, LLC for financial support of this research (Grant number 19ERGPAR‐01‐01).

Publisher Copyright:
© 2022 John Wiley & Sons Ltd.


  • cyathostomins
  • goblet cell
  • inflammatory response
  • ivermectin
  • larvicidal
  • moxidectin

ASJC Scopus subject areas

  • Parasitology
  • Immunology


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