Four decades of research with these herds have led to numerous publications reporting the following results:

  • Epidemiology of important equine parasites. Impact of age, seasonality and immunity.
  • Documentation of how parasites responded to typical deworming schedules by becoming multi-drug resistant.
  • Documentation of how drug resistance does not disappear once it has developed, regardless of whether the horses are dewormed or not.
  • Development of new diagnostic methods for detection of important equine parasites, including a blood test for bloodworms, and ultrasound method for ascarids, and a smartphone-based automated egg counting system.
  • Evaluation of novel deworming programs, such as various forms of combination-deworming.
  • Molecular studies of mechanisms behind drug resistance.

Parasitology herd

Complete reference list:

      1. Lyons, E.T., Drudge, J.H., Tolliver, S.C., 1973.  On the life cycle of Strongyloides westeri in the equine.  J. Parasitol. 59, 780-787.
      2. Lyons, E.T., J.H. Drudge, S.C. Tolliver, 1976. Thelazia lacrymalis in horses in Kentucky and observations on the face fly (Musca autumnalis) as a possible intermediate host.  J. Parasitol. 62, 877-880.
      3. Lyons, E. T., S. C. Tolliver, J. H. Drudge, 1983. Critical tests in equids with fenbendazole alone or combined with piperazine: Particular reference to activity on benzimidazole resistant small strongyles. Vet. Parasitol. 12, 91-98.
      4. Drudge, J. H., E. T. Lyons, T. W. Swerczek, S. C. Tolliver, 1983. Cambendazole for strongyle control in a pony band: Selection of a drug-resistant population of small strongyles and teratologic implications. Am. J. Vet. Res. 44, 110-114.
      5. Drudge, J. H., E. T. Lyons, S. C. Tolliver, T. W. Swerczek, 1985. Use of oxibendazole for control of cambendazole-resistant small strongyles in a band of ponies: A six year study. Am. J. Vet. Res. 46, 2507-2511.
      6. Lyons, E. T., J. H. Drudge, S. C. Tolliver, 1986. Fenbendazole in equids: further controlled tests with emphasis on activity of multiple doses against naturally occurring infections of migratory large strongyles. Am. J. Vet. Res. 47, 317-321.
      7. Lyons, E. T., J. H. Drudge, S. C. Tolliver, 1990. Prevalence of some internal parasites found (1971-1989) in horses born on a farm in central Kentucky. J. Equine Vet. Sci. 10, 99-107.
      8. Lyons, E.T., S.C. Tolliver, J.H. Drudge, D.E. Granstrom, S. Stamper, S.S. Collins, 1991. Transmission of some internal parasites in horses born in 1989 on a farm in central Kentucky. J. Helm. Soc. Wash. 58, 213-219.
      9. Lyons, E.T., J.H. Drudge, S.C. Tolliver, T.W. Swerczek, S. Stamper, D.E. Granstrom, 1994. Control of cambendazole-resistant small strongyles (Population S) with oxibendazole in a pony band: An 8 year field test (1984-1992). Vet. Parasit. 52, 271-277.
      10. Lyons, E.T., S.C. Tolliver, S. Stamper, J.H. Drudge, D.E. Granstrom, S.S. Collins, 1994. Transmission of some species of internal parasites in horses born in 1990, 1991, and 1992 in the same pasture on a farm in central Kentucky. Vet. Parasit. 52, 257-269.
      11. Lyons, E.T., Tolliver, S.C., Drudge, J.H., Stamper, S., Swerczek, T.W., Granstrom, D.E., 1996.  Critical test evaluation (1977-1992) of drug efficacy against endoparasites featuring benzimidazole-resistant small strongyles (Population S) in Shetland ponies.  Vet. Parasitol. 66, 67-73.
      12. Lyons, E.T., Tolliver, S.C., Drudge, J.H,. Stamper, S., Swerczek, T.W., Granstrom, D.E., 1996.  A study (1977-1992) of population dynamics of endoparasites featuring benzimidazole-resistant small strongyles (Population S) in Shetland ponies.  Vet. Parasitol. 66, 75-86.
      13. Lyons, E.T., Tolliver, S.C., Collins, S.S., Drudge, J.H., Granstrom, D.E., 1997.  Transmission of some species of internal parasites in horses born in 1993, 1994, and 1995 on the same pasture on a farm in central Kentucky.  Vet. Parasitol. 70: 225-240.
      14. Lyons, E.T., Tolliver, S.C., Drudge, J.H., Collins, S.S. Swerczek, T.W., 2001.  Continuance of studies on Population S benzimidazole-resistant small strongyles in Shetland pony herd in Kentucky: effect of pyrantel pamoate (1992-1999).  Vet. Parasitol. 94, 247-256.
      15. Lyons, E.T., Tolliver, S.C., Collins, S.S., Drudge, J.H., 2001.  Transmission of endoparasites in horse foals on the same pasture on a farm in central Kentucky (1996-1999).  Vet. Parasitol. 97, 113-121.
      16. Lyons, E.T., 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, 407-411.
      17. Tandon, R., Kaplan, R.M., 2004. Evaluation of a larval development assay (DrenchRite) for the detection of anthelmintic resistance in cyathostomin nematodes of horses. Vet. Parasitol. 121, 125-142
      18. Tandon, R., Lyons, E.T., Tolliver, S.C., Kaplan, R.M., 2005.  Effect of moxidectin selection on the genetic variation within Cylicocyclus nassatus based on amplified fragment length polymorphism (AFLP).  Int. J. Parasitol. 35, 813-819.
      19. Nielsen, M.K., Peterson, D.S., Monrad, J., Thamsborg, S.M., Olsen, S.N., Kaplan, R.M., 2008. Detection and semi-quantification of Strongylus vulgaris DNA in equine faeces by real-time quantitative PCR. Int. J. Parasitol. 38, 443-453.
      20. Nielsen, M.K., Baptiste, K.E., Tolliver, S.C., Collins, S.S., Lyons, E.T., 2010. Analysis of multiyear studies in horses in Kentucky to ascertain whether counts of eggs and larvae per gram of feces are reliable indicators of numbers of strongyles and ascarids present.  Vet. Parasitol. 174, 77-84.
      21. Kuzmina, T.A., Tolliver, S.C., Lyons, E.T., 2011.  Three recently recognized species of cyathostomes (Nematoda: Strongylidae) in equids in Kentucky.  Parasitol. Res. 108, 1179-1184.
      22. Lyons, E.T., Kuzmina, T.A., Tolliver, S.C., Collins, S.S., 2011.  Observations on development of natural infection and species composition of small strongyles in young equids in Kentucky.  Parasitol. Res. 109, 1529-1535.
      23. Kuzmina, T.A., E. T. Lyons, S. C. Tolliver, I.I. Dzeverin, V.A. Kharchenko, 2012.  Fecundity of various species of strongylids (Nematoda: Strongylidae) – parasites of domestic horses. Parasitol. Res. 111, 2265-2271.
      24. Tyden, E., Morrison, D.A., Engstrom, A., Nielsen, M.K., Eydal, E., Hoglund, J., 2013. Population genetics of Parascaris equorum based on whole genome DNA fingerprinting. Infect. Genet. Evol. 13, 236-241.
      25. Andersen, U.V., Howe, D.K., Dangoudoubiyam, S., Toft, N., Reinemeyer, C.R., Lyons, E.T., Olsen, S.N., Monrad, J., Nejsum, P., Nielsen, M.K., 2013.  rSvSXP: A Strongylus vulgaris antigen with potential for prepatent diagnosis. Parasite Vector 6, 84.
      26. Nielsen, M.K., Betancourt, A., Lyons, E.T., Horohov, D.W., Jacobsen, S., 2013. Characterization of the inflammatory response to anthelmintic treatment in ponies naturally infected with cyathostomin parasites. Vet. J. 198, 457-462.
      27. Nielsen, M.K., Vidyashankar, A.N., Gravatte, H.S., Bellaw, J., Lyons, E.T., Andersen, U.V., 2014. Development of Strongylus vulgaris-specific serum antibodies in naturally infected foals. Vet. Parasitol. 200, 233-304.
      28. Nielsen, M.K., Wang, J., Davis, R., Bellaw, J.L., Lyons, E.T., Lear, T.L., Goday, C., 2014. Parascaris univalens – a victim of large-scale misidentification? Parasitol. Res.113, 4485-4490.
      29. Bellaw, J.L., Nielsen, M.K., 2015. Evaluation of Baermann apparatus sedimentation time on recovery of Strongylus vulgaris and S. edentatus third stage larvae from equine coprocultures. Vet. Parasitol. 211, 99-101.
      30. Tolliver, S.C., Lyons, E.T., Nielsen, M.K., Bellaw, J., 2015. Transmission of some species of internal parasites in horse foals born in 2013 in the same pasture on a farm in Central Kentucky. Helminthologia 52, 211-218.
      31. Donoghue, E.M., Lyons, E.T., Bellaw, J.L., Nielsen, M.K., 2015. Biphasic appearance of corticated and decorticated ascarid egg shedding in untreated horse foals. Vet. Parasitol. 214, 114-117.
      32. Nielsen, M.K., Donoghue, E.M., Stephens, M.L., Stowe, C.J., Donecker, J.M., Fenger, C.K., 2016. An ultrasonographic scoring method for transabdominal monitoring of ascarid burdens in foals. Equine Vet. J. 48, 380-386.
      33. Slusarewicz, P., Pagano, S., Mills, C., Popa, G., Chow, M., Mendenhall, M., Rodgers, D.W., Nielsen, M.K., 2016. Automated parasite fecal egg counting using fluorescence labeling, smartphone image capture and computational image analysis. Int. J. Parasitol. 46, 485-493.
      34. Fabiani, J.V., Lyons, E.T., Nielsen, M.K., 2016. Dynamics of Parascaris and Strongylus spp. parasites in untreated juvenile horses. Vet. Parasitol. 30, 62-66.
      35. Nielsen, M.K., Lyons, E.T., 2017. Encysted cyathostomin larvae in foals - progression of stages and the effect of seasonality. Vet. Parasitol. 236, 108-112.
      36. Noel, M.L., Scare, J.A., Bellaw, J.L., Nielsen, M.K., 2017. Accuracy and precision of Mini-FLOTAC and McMaster techniques for determining equine strongyle egg counts. J. Equine Vet. Sci. 48, 182-187.
      37. Pihl, T., Nielsen, M.K., Jacobsen, S., 2017. Changes in hemostatic indices in foals naturally infected with Strongylus vulgaris. J. Equine Vet. Sci. 54, 1-
      38. Scare J.A., Slusarewicz P., Noel M.L., Wielgus K.M., Nielsen M.K., 2017. Evaluation of accuracy and precision of a smartphone based automated parasite egg counting system in comparison to the McMaster and Mini-FLOTAC method. Vet. Parasitol. 247, 85-92.
      39. Miller, F.L., Bellaw, J.L., Lyons, E.T., Nielsen, M.K., 2017. Strongyloides westeri worm and egg counts in naturally infected young horses. Vet. Parasitol. 15, 1-3.
      40. Wang, J., Gao, S., Mostovoy, Y., Kang, Y., Zagoskin, M., Sun, Y., Zhang, B., White, L.K.,  Easton, A., Nutman, T.B., Kwok,P.-Y.,  Hu, S.,  Nielsen, M.K., Davis, R.E., 2017. Comparative Genome Analysis of Programmed DNA Elimination in Nematodes. Genome Research 27, 1-14.
      41. Scare, J.A., Lyons, E.T., Wielgus, K.M., Nielsen, M.K., 2018. Combination deworming for the control of double-resistant cyathostomin parasites – short and long term consequences. Veterinary Parasitology 251, 112-118.
      42. Hu, Y., Miller, M., Zhang, B., Nguyen, T.-T., Nielsen, M.K., Aroian, R.V., 2018. In vivo and in vitro studies of Cry5B and nicotinic acetylcholine receptor agonist anthelmintics reveal a powerful and unique combination therapy against intestinal nematode parasites. PLoS Neglected Tropical Diseases 12(5), e0006506.
      43. Janečka, J., Davis, B., Ghosh, S., Paria, N., Das, P., Orlando, L., Schubert, M., Nielsen, M.K., Stout, T., Brashear, W., Li, G., Johnson, C., Metz, R., Al Zadjali, A.M., Love, C., Varner, D., Bellott, D., Murphy, W., Chowdhary, B., Raudsepp, T., 2018. Horse Y chromosome assembly displays unique evolutionary features and putative stallion fertility genes. Nature Communications 9, 2945.
      44. Norris, J.K., Steuer, A.E., Slusarewicz, P., Scare, J.A., Bellaw, J.L., Nielsen, M.K., 2018. Determination of the specific gravity of eggs of equine strongylids, Parascaris spp., and Anoplocephala perfoliata. Veterinary Parasitology 260, 45-48.
      45. Went, H.A., Scare, J.A., Steuer, A.E., Nielsen, M.K., 2018. Effects of homogenizing methods on accuracy and precision of equine strongylid egg counts. Veterinary Parasitology 261, 91-95.
      46. Scare, J.A., Steuer A.E., Shaffer C.L., Slusarewicz P., Mousley A., Nielsen M.K., 2019. Long live the worms: Methods for maintaining and assessing the viability of intestinal stages of Parascaris spp. in vitro. Parasitology – in press.