Anthelmintic resistance in equine helminth parasites – a growing issue for horse owners and veterinarians in New Zealand?

References

• Allison K, Taylor NM, Wilsmore AJ, Garforth C. Equine anthelmintics: survey of the patterns of use, belief and attitudes among horse owners in the UK. The Veterinary Record 168, 483–7, 2011 doi: 10.1136/vr.d731
   PubMed Web of Science ®Google Scholar
• Andersen UV, Howe DK, Dangoudoubiyam S, Toft N, Reinemeyer CR, Lyons ET, Olsen SN, Monrad J, Nejsum P, Nielsen MK. SvSXP: a Strongylus vulgaris antigen with potential for prepatent diagnosis. Parasites and Vectors 6, 84, 2013 doi: 10.1186/1756-3305-6-84
   PubMed Web of Science ®Google Scholar
• *Anonymous. AAEP Parasite Control Guidelines. http://www.aaep.org/custdocs/ParasiteControlGuidelinesFinal.pdf (accessed 26 August 2014) American Association of Equine Practitioners, Lexington, Kentucky, USA, 2013
   Google Scholar
• Back H, Nyman A, Lind EO. The association between Anoplocephala perfoliata and colic in Swedish horses – A case control study. Veterinary Parasitology 197, 580–5, 2013 doi: 10.1016/j.vetpar.2013.07.020
   PubMed Web of Science ®Google Scholar
• Bairden K, Brown SR, McGoldrick J, Parker LD, Talty PJ. Efficacy of moxidectin 2 per cent gel against naturally acquired strongyle infections in horses, with particular reference to larval cyathostomes. The Veterinary Record 148, 138–41, 2001 doi: 10.1136/vr.148.5.138
   PubMed Web of Science ®Google Scholar
• Bairden K, Davies HS, Gibson NR, Hood AJO, Parker LD. Efficacy of moxidectin 2 per cent oral gel against cyathostomins, particularly third-stage inhibited larvae, in horses. The Veterinary Record 158, 766–8, 2006 doi: 10.1136/vr.158.22.766
   PubMed Web of Science ®Google Scholar
• Barker SA. The formation of aminorex in racehorses following levamisole administration. A quantitative and chiral analysis following synthetic aminorex or levamisole administration vs. aminorex-positive samples from the field: a preliminary report. Journal of Veterinary Pharmacology and Therapeutics 32, 160–6, 2009 doi: 10.1111/j.1365-2885.2008.01015.x
   PubMed Web of Science ®Google Scholar
• Bartram DJ, Leathwick DM, Taylor MA, Geurden T, Maeder SJ. The role of combination anthelmintic formulations in the sustainable control of sheep nematodes. Veterinary Parasitology 186, 151–8, 2012 doi: 10.1016/j.vetpar.2011.11.030
   PubMed Web of Science ®Google Scholar
• Bishop RM, Scott I, Gee EK, Rogers CW, Pomroy WE, Mayhew IG. Sub-optimal efficacy of ivermectin against Parascaris equorum in foals on three Thoroughbred stud farms in the Manawatu region of New Zealand. New Zealand Veterinary Journal 62, 91–5, 2014 doi: 10.1080/00480169.2013.843146
   PubMed Web of Science ®Google Scholar
• Boersema JH, Eysker M, Nas JWM. Apparent resistance of Parascaris equorum to macrocyclic lactones. Veterinary Record 150, 279–81, 2002 doi: 10.1136/vr.150.9.279
   PubMed Web of Science ®Google Scholar
• *Bolwell CF, Rosanowski SM, Scott I, Sells PD. A cross-sectional survey of parasite control practices on stud farms in New Zealand. Proceedings of the Australasian Equine Science Symposium 5, P 51, 2014
   Google Scholar
• Brady HA, Nichols WT. Drug resistance in equine parasites: an emerging global problem. Journal of Equine Veterinary Science 29, 285–95, 2009 doi: 10.1016/j.jevs.2009.04.186
   Web of Science ®Google Scholar
• *Brady HA, Nichols WT, Blanek M, Hutcheson DP. Parasite resistance and the effects of rotational deworming regimens in horses. Proceedings of the 54^th Annual Convention of the American Association of Equine Practitioners 54, Pp 308–13, 2008
   Google Scholar
• Chandler KL, Love S. Patterns of equine faecal egg counts following spring dosing with either fenbendazole or moxidectin. The Veterinary Record 151, 269–70, 2002 doi: 10.1136/vr.151.9.269
   PubMed Web of Science ®Google Scholar
• Chapman MR, French DD, Monahan CM, Klei TR. Identification and characterization of a pyrantel pamoate resistant cyathostomin population. Veterinary Parasitology 66, 205–12, 1996 doi: 10.1016/S0304-4017(96)01014-X
   PubMed Web of Science ®Google Scholar
• Coles GC, Bauer C, Borgsteede FHM, Geerts S, Klei TR, Taylor MA, Waller PJ. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) methods for the detection of anthelmintic resistance in nematodes of veterinary importance. Veterinary Parasitology 44, 35–44, 1992 doi: 10.1016/0304-4017(92)90141-U
   PubMed Web of Science ®Google Scholar
• Craig TM, Diamond PL, Ferwerda NS, Thompson JA. Evidence of ivermectin resistance by Parascaris equorum on a Texas horse farm. Journal of Equine Veterinary Science 27, 67–71, 2007 doi: 10.1016/j.jevs.2006.12.002
   Web of Science ®Google Scholar
• Denwood MJ, Reid SWJ, Love S, Nielsen MK, Matthews L, McKendrick IJ, Innocent GT. Comparison of three alternative methods for analysis of equine Faecal Egg Count Reduction Test data. Preventative Veterinary Medicine 93, 316–23, 2010 doi: 10.1016/j.prevetmed.2009.11.009
   PubMed Web of Science ®Google Scholar
• DiPietro JA, Todd KS. Anthelmintics used in treatment of parasitic infections of horses. Veterinary Clinics of North America – Equine Practice 3, 1–14, 1987
   PubMed Web of Science ®Google Scholar
• Dopfer D, Kerssens CM, Meijer YGM, Boersema JH, Eysker M. Shedding consistency of strongyle-type eggs in dutch boarding horses. Veterinary Parasitology 124, 249–58, 2004 doi: 10.1016/j.vetpar.2004.06.028
   PubMed Web of Science ®Google Scholar
• Drudge JH. Clinical aspects of Strongylus vulgaris infection in the horse. Emphasis on diagnosis, chemotherapy and prophylaxis. The Veterinary Clinics of North America. Large Animal Practice 1, 251–65, 1979
   PubMedGoogle Scholar
• *Drudge JH and Lyons ET. Newer developments in helminth control and Strongylus vulgaris research. Proceedings of the 11^th Annual Convention of the American Association of Equine Practitioners. Pp 381–9, 1965
   Google Scholar
• Duncan JL, Love S. Preliminary observations on an alternative strategy for the control of horse strongyles. Equine Veterinary Journal 23, 226–8, 1991 doi: 10.1111/j.2042-3306.1991.tb02762.x
   PubMed Web of Science ®Google Scholar
• Earle CG, Kington HA, Coles GC. Helminth control used by trainers of thoroughbreds in England. The Veterinary Record 150, 405–8, 2002 doi: 10.1136/vr.150.13.405
   PubMed Web of Science ®Google Scholar
• Gomez HH, Georgi JR. Equine helminth infections: control by selective chemotherapy. Equine Veterinary Journal 23, 198–200, 1991 doi: 10.1111/j.2042-3306.1991.tb02754.x
   PubMed Web of Science ®Google Scholar
• Gopal RM, West DM, Pomroy WE. The difference in efficacy of ivermectin oral, moxidectin oral and moxidectin injectable formulations against an ivermectin-resistant strain of Trichostrongylus colubriformis in sheep. New Zealand Veterinary Journal 49, 133–7, 2001 doi: 10.1080/00480169.2001.36220
   PubMed Web of Science ®Google Scholar
• Hearn FPD, Peregrine AS. Identification of foals infected with Parascaris equorum apparently resistant to ivermectin. Journal of the American Veterinary Medical Association 223, 482–5, 2003 doi: 10.2460/javma.2003.223.482
   PubMed Web of Science ®Google Scholar
• Hope JJ, Kemp GK. Apparent Trichonema resistance to fenbendazole. New Zealand Veterinary Journal 28, 80, 1980 doi: 10.1080/00480169.1980.34700
   Web of Science ®Google Scholar
• Horner RF. Malignant edema caused by Clostridium perfringens type-A in a horse. Journal of the South African Veterinary Association 53, 122–3, 1982
   PubMed Web of Science ®Google Scholar
• *Islam Z. Development of a novel equine combination anthelmintic and a study of anthelmintic susceptibility using a larval development assay. MPhil thesis, Massey University, Palmerston North, NZ, 2000
   Google Scholar
• Kaplan RM. Anthelmintic resistance in nematodes of horses. Veterinary Research 33, 491–507, 2002 doi: 10.1051/vetres:2002035
   PubMed Web of Science ®Google Scholar
• Kaplan RM, Nielsen MK. An evidence-based approach to equine parasite control: it ain't the 60s anymore. Equine Veterinary Education 22, 306–16, 2010 doi: 10.1111/j.2042-3292.2010.00084.x
   Web of Science ®Google Scholar
• Kaplan RM, Klei TR, Lyons ET, Lester G, Courtney CH, French DD, Tolliver SC, Vidyashankar AN, Zhao Y. Prevalence of anthelmintic resistant cyathostomins on horse farms. Journal of the American Veterinary Medical Association 225, 903–10, 2004 doi: 10.2460/javma.2004.225.903
   PubMed Web of Science ®Google Scholar
• Kelly JD, Webster JH, Griffin DL, Whitlock HV, Martin ICA, Gunawan M. Resistance to benzimidazoles anthelmintics in equine strongyles 1. Frequency, geographical distribution and relationship between occurrence, animal husbandry procedures and anthelmintic usage. Australian Veterinary Journal 57, 163–71, 1981 doi: 10.1111/j.1751-0813.1981.tb00503.x
   PubMed Web of Science ®Google Scholar
• Kuzmina TA, Lyons ET, Tolliver SC, Dzeverin II, Kharchenko VA. Fecundity of various species of strongylids (Nematoda: Strongylidae) – parasites of domestic horses. Parasitology Research 111, 2265–71, 2012 doi: 10.1007/s00436-012-3077-5
   PubMed Web of Science ®Google Scholar
• Leathwick DM. Managing anthelmintic resistance – parasite fitness, drug use strategy and the potential for reversion towards susceptibility. Veterinary Parasitology 198, 145–53, 2013 doi: 10.1016/j.vetpar.2013.08.022
   PubMed Web of Science ®Google Scholar
• Leathwick DM, Moen IC, Miller CM, Sutherland IA. Ivermectin-resistant Ostertagia circumcincta from sheep in the lower North Island and their susceptibility to other macrocyclic lactone anthelmintics. New Zealand Veterinary Journal 48, 151–4, 2000 doi: 10.1080/00480169.2000.36183
   PubMed Web of Science ®Google Scholar
• Leathwick DM, Waghorn TS, Miller CM, Candy PM, Oliver A-MB. Managing anthelmintic resistance – use of a combination anthelmintic and leaving some lambs untreated to slow the development of resistance to ivermectin. Veterinary Parasitology 187, 285–94, 2012 doi: 10.1016/j.vetpar.2011.12.021
   PubMed Web of Science ®Google Scholar
• Lester HE, Matthews JB. Faecal worm egg count analysis for targeting anthelmintic treatment in horses: points to consider. Equine Veterinary Journal 46, 139–45, 2014 doi: 10.1111/evj.12199
   PubMed Web of Science ®Google Scholar
• Lester HE, Bartley DJ, Morgan ER, Hodgkinson JE, Stratford CH, Matthews JB. A cost comparison of faecal egg count-directed anthelmintic delivery versus interval programme treatments in horses. The Veterinary Record 173, 371–4, 2013 doi: 10.1136/vr.101804
   PubMed Web of Science ®Google Scholar
• Lichtenfels JR, Kharchenko VA, Dvojnos GM. Illustrated identification keys to strongylid parasites (strongylidae: Nematoda) of horses, zebras and asses (Equidae). Veterinary Parasitology 156, 4–161, 2008 doi: 10.1016/j.vetpar.2008.04.026
   PubMed Web of Science ®Google Scholar
• Lindgren K, Ljungvall O, Nilsson O, Ljungstrom B-L, Lindahl C, Hoglund J. Parascaris equorum in foals and in their environment on a Swedish stud farm, with notes on treatment failure of ivermectin. Veterinary Parasitology 151, 337–43, 2008 doi: 10.1016/j.vetpar.2007.10.014
   PubMed Web of Science ®Google Scholar
• Lloyd S, Smith J, Connan RM, Hatcher MA, Hedges TR, Humphrey DJ, Jones AC. Parasite control methods used by horse owners: factors predisposing to the development of anthelmintic resistance in nematodes. The Veterinary Record 146, 487–92, 2000 doi: 10.1136/vr.146.17.487
   PubMed Web of Science ®Google Scholar
• Love S, Murphy D, Mellor D. Pathogenicity of cyathostome infection. Veterinary Parasitology 85, 113–22, 1999 doi: 10.1016/S0304-4017(99)00092-8
   PubMed Web of Science ®Google Scholar
• *Lowe J. Anthelmintic resistance of Parascaris equorum to ivermectin on a New Zealand thoroughbred horse farm. The Equine Veterinary Practitioner 34, 12–7, 2010
   Google Scholar
• Lyons ET, Tolliver SC. Further indication of lowered activity of ivermectin on immature small strongyles in the intestinal lumen of horses on a farm in Central Kentucky. Parasitology Research 112, 889–91, 2013 doi: 10.1007/s00436-012-3098-0
   PubMed Web of Science ®Google Scholar
• Lyons ET, Tolliver SC, Collins SS. Study (1991–2001) of drug-resistant Population B small strongyles in critical tests in horses in Kentucky at the termination of a 40-year investigation. Parasitology Research 101, 689–701, 2007 doi: 10.1007/s00436-007-0535-6
   PubMed Web of Science ®Google Scholar
• Lyons ET, Tolliver SC, Collins SS. Probable reason why small strongyle EPG counts are returning “early” after ivermectin treatment of horses on a farm in Central Kentucky. Parasitology Research 104, 569–74, 2009 doi: 10.1007/s00436-008-1231-x
   PubMed Web of Science ®Google Scholar
• Lyons ET, Tolliver SC, Kuzmina TA, Collins SS. Critical tests evaluating efficacy of moxidectin against small strongyles in horses from a herd for which reduced activity had been found in field tests in Central Kentucky. Parasitology Research 107, 1495–8, 2010 doi: 10.1007/s00436-010-2025-5
   PubMed Web of Science ®Google Scholar
• Lyons ET, Tolliver SC, Collins SS, Ionita M, Kuzmina TA, Rossano M. Field tests demonstrating reduced activity of ivermectin and moxidectin against small strongyles in horses on 14 farms in Central Kentucky in 2007–2009. Parasitology Research 108, 355–60, 2011a doi: 10.1007/s00436-010-2068-7
   PubMed Web of Science ®Google Scholar
• Lyons ET, Tolliver SC, Kuzmina TA, Collins SS. Further evaluation in field tests of the activity of three anthelmintics (fenbendazole, oxibendazole and pyrantel pamoate) against the ascarid Parascaris equorum in horse foals on eight farms in Central Kentucky (2009–2010). Parasitology Research 109, 1193–7, 2011b doi: 10.1007/s00436-011-2379-3
   PubMed Web of Science ®Google Scholar
• Maclean JM, Lewis D, Holmes PH. The pathogenesis of benzimidazole-resistant and benzimidazole-susceptible strains of Trichostrongylus colubriformis in the Mongolian gerbil (Meriones unguiculatis). Journal of Helminthology 61, 179–89, 1987 doi: 10.1017/S0022149X00009962
   PubMed Web of Science ®Google Scholar
• Maingi N, Scott ME, Prichard RK. Effect of selection pressure for thiabendazole resistance on fitness of Haemonchus contortus in sheep. Parasitology 100, 327–35, 1990 doi: 10.1017/S0031182000061345
   PubMed Web of Science ®Google Scholar
• Martin PJ, Anderson N, Brown TH, Miller DW. Changes in resistance of Ostertagia spp. to thiabendazole following natural selection or treatment with levamisole. International Journal for Parasitology 18, 333–40, 1988 doi: 10.1016/0020-7519(88)90142-7
   PubMed Web of Science ®Google Scholar
• Matthews JB, McArthur C, Robinson A, Jackson F. The in vitro diagnosis of anthelmintic resistance in cyathostomins. Veterinary Parasitology 185, 25–31, 2012 doi: 10.1016/j.vetpar.2011.10.014
   PubMed Web of Science ®Google Scholar
• McKenna PB. An updated checklist of helminth and protozoan parasites of terrestrial mammals in New Zealand. New Zealand Journal of Zoology 36, 89–113, 2009 doi: 10.1080/03014220909510145
   Web of Science ®Google Scholar
• McWilliam HEG, Nisbet AJ, Dowdall SMJ, Hodgkinson JE, Matthews JB. Identification and characterisation of an immunodiagnostic marker for larval cyathostomin developing stage larvae. International Journal for Parasitology 40, 265–75, 2010 doi: 10.1016/j.ijpara.2009.08.004
   PubMed Web of Science ®Google Scholar
• *Mirck MH. Chemotherapy of gastrointestinal nematodiasis in equines. In: Bossche H vanden, Thienpont D, Janssens PG (eds). Handbook of Experimental Pharmacology Vol. 77. Pp 443–462. Springer-Verlag, Berlin, Germany, 1985
   Google Scholar
• Molento MB, Antunes J, Bentes RN, Coles GC. Anthelmintic resistant nematodes in Brazilian horses. The Veterinary Record 162, 384–5, 2008 doi: 10.1136/vr.162.12.384
   PubMed Web of Science ®Google Scholar
• Molento MB, Nielsen MK, Kaplan RM. Resistance to avermectin/milbemycin anthelmintics in equine cyathostomins – Current situation. Veterinary Parasitology 185, 16–24, 2012 doi: 10.1016/j.vetpar.2011.10.013
   PubMed Web of Science ®Google Scholar
• Monahan CM, Chapman MR, Taylor HW, French DD, Klei TR. Comparison of moxidectin oral gel and ivermectin oral paste against a spectrum of internal parasites of ponies with special attention to encysted cyathostome larvae. Veterinary Parasitology 63, 225–35, 1996 doi: 10.1016/0304-4017(95)00910-8
   PubMed Web of Science ®Google Scholar
• *Morris L, Colgan S. Confirmation of resistance of ascarids to ivermectin and praziquantel in New Zealand. Proceedings of the Annual Seminar of the Equine Branch of the New Zealand Veterinary Association. Pp 3.20.1–3.20.3, 2012
   Google Scholar
• Nation PN, Frelier PF, Schoonderwoerd M. Clostridial myositis following ivermectin administration. Canadian Veterinary Journal 24, 295, 1983
   PubMed Web of Science ®Google Scholar
• Nielsen MK. Restrictions of anthelmintic usage: perspectives and potential consequences. Parasites and Vectors 2 (Suppl. 2), S7, 2009 doi: 10.1186/1756-3305-2-S2-S7
   PubMed Web of Science ®Google Scholar
• Nielsen MK. Sustainable equine parasite control: perspectives and research needs. Veterinary Parasitology 185, 32–44, 2012 doi: 10.1016/j.vetpar.2011.10.012
   PubMed Web of Science ®Google Scholar
• Nielsen MK, Haaning N, Olsen SN. Strongyle egg shedding consistency in horses on farms using selective therapy in Denmark. Veterinary Parasitology 135, 333–5, 2006 doi: 10.1016/j.vetpar.2005.09.010
   PubMed Web of Science ®Google Scholar
• Nielsen MK, Baptiste KE, Tolliver SC, Collins SS, Lyons ET. Analysis of multiyear studies in horses in Kentucky to ascertain whether counts of eggs and larvae per gram of faeces are reliable indicators of numbers of strongyles and ascarids present. Veterinary Parasitology 174, 77–84, 2010 doi: 10.1016/j.vetpar.2010.08.007
   PubMed Web of Science ®Google Scholar
• Nielsen MK, Vidyashankar AN, Olsen SN, Monrad J, Thamsborg SM. Strongylus vulgaris associated with usage of selective therapy on Danish horse farms – is it reemerging? Veterinary Parasitology 189, 260–6, 2012 doi: 10.1016/j.vetpar.2012.04.039
   PubMed Web of Science ®Google Scholar
• Nielsen MK, Vidyashankar AN, Hanlon BM, Diao G, Petersen SL, Kaplan RM. Hierarchical model for evaluating pyrantel efficacy against strongyle parasites in horses. Veterinary Parasitology 197, 614–22, 2013 doi: 10.1016/j.vetpar.2013.04.036
   PubMed Web of Science ®Google Scholar
• *Ogbourne CP. Pathogenesis of Cyathostomin (Trichonema) Infections of the Horse. A Review. Commonwealth Agricultural Bureaux, Slough, UK, 1978
   Google Scholar
• *Ogbourne CP, Duncan JL. Strongylus Vulgaris in the Horse: Its Biology and Veterinary Importance. 2nd Edtn. Commonwealth Agricultural Bureaux, Slough, United Kingdom, 1985
   Google Scholar
• O'Meara B, Mulcahy G. A survey of helminth control practices in equine establishments in Ireland. Veterinary Parasitology 109, 101–10, 2002 doi: 10.1016/S0304-4017(02)00249-2
   PubMed Web of Science ®Google Scholar
• Owen Rh ap Rh, Jagger DW, Quan-Taylor R. Caecal intussusceptions in horses and the significance of Anoplocephala perfoliata. The Veterinary Record 124, 34–7, 1989 doi: 10.1136/vr.124.2.34
   PubMed Web of Science ®Google Scholar
• Peek SF, Semrad SD, Perkins GA. Clostridial myonecrosis in horses (37 cases 1985–2000). Equine Veterinary Journal 35, 86–92, 2003 doi: 10.2746/042516403775467513
   PubMed Web of Science ®Google Scholar
• Perez R, Cabezas I, Garcia M, Rubilar L, Sutra JF, Galtier P, Alvinerie M. Comparison of the pharmacokinetics of moxidectin (Equest®) and ivermectin (Eqvalan®) in horses. Journal of Veterinary Pharmacology and Therapeutics 22, 174–80, 1999 doi: 10.1046/j.1365-2885.1999.00200.x
   PubMed Web of Science ®Google Scholar
• Prichard RK. Anthelmintic resistance in nematodes: extent, recent understanding and future directions for control and research. International Journal for Parasitology 20, 515–23, 1990 doi: 10.1016/0020-7519(90)90199-W
   PubMed Web of Science ®Google Scholar
• Proudman CJ, French NP, Trees AJ. Tapeworm infection is a significant risk factor for spasmodic colic and ileal impaction colic in the horse. Equine Veterinary Journal 30, 194–9, 1998 doi: 10.1111/j.2042-3306.1998.tb04487.x
   PubMed Web of Science ®Google Scholar
• Reavell DG. Measuring and estimating the weight of horses with tapes, formulae and by visual assessment. Equine Veterinary Education 11, 314–7, 1999 doi: 10.1111/j.2042-3292.1999.tb01562.x
   Web of Science ®Google Scholar
• Rebhun WC, Shin SJ, King JM, Baum KH, Patten V. Malignant edema in horses. Journal of the American Veterinary Medical Association 187, 732–6, 1985
   PubMed Web of Science ®Google Scholar
• *Reinemeyer CR. Controlling parasites of horses: a mandate for change. Proceedings of the 55^th Annual Convention of the American Association of Equine Practitioners 55, Pp 352–60, 2009
   Google Scholar
• Reinemeyer CR, Prado JC, Nichols EC, Marchiondo AA. Efficacy of pyrantel pamoate and ivermectin paste formulations against naturally acquired Oxyuris equi infections in horses. Veterinary Parasitology 171, 106–10, 2010 doi: 10.1016/j.vetpar.2010.02.042
   PubMed Web of Science ®Google Scholar
• Relf VE, Morgan ER, Hodgkinson JE, Matthews JB. A questionnaire study on parasite control practices on UK breeding Thoroughbred studs. Equine Veterinary Journal 44, 466–71, 2012 doi: 10.1111/j.2042-3306.2011.00493.x
   PubMed Web of Science ®Google Scholar
• *Rock C, Pomroy WE, Gee E, Scott I. Macrocyclic lactone resistant Oxyuris equi in New Zealand. Proceedings of the 24^th International Conference of the World Association for the Advancement of Veterinary Parasitology. 2013
   Google Scholar
• Rogers CW, Gee EK, Firth EC. A cross-sectional survey of Thoroughbred stud farm management in the North Island of New Zealand. New Zealand Veterinary Journal 55, 302–7, 2007 doi: 10.1080/00480169.2007.36785
   PubMed Web of Science ®Google Scholar
• Russell AF. The development of helminthiasis in Thoroughbred foals. Journal of Comparative Pathology and Therapeutics 58, 107–27, 1948 doi: 10.1016/S0368-1742(48)80009-3
   PubMed Web of Science ®Google Scholar
• von Samson-Himmelstjerna G, Fritzen B, Demeler J, Schurmann S, Rohn K, Schneider T, Epe C. Cases of reduced cyathostomin egg re-appearance period and failure of Parascaris equorum egg count reduction following ivermectin treatment as well as survey on pyrantel efficacy on German horse farms. Veterinary Parasitology 144, 74–80, 2007 doi: 10.1016/j.vetpar.2006.09.036
   PubMed Web of Science ®Google Scholar
• Sangster NC. Pharmacology of anthelmintic resistance in cyathostomins: will it occur with the avermectin/milbemycins? Veterinary Parasitology 85, 189–204, 1999 doi: 10.1016/S0304-4017(99)00099-0
   PubMed Web of Science ®Google Scholar
• Schougaard H, Nielsen MK. Apparent ivermectin resistance of Parascaris equorum in foals in Denmark. The Veterinary Record 160, 439–40, 2007 doi: 10.1136/vr.160.13.439
   PubMed Web of Science ®Google Scholar
• Schumacher J, Taintor J. A review of the use of moxidectin in horses. Equine Veterinary Education 20, 546–51, 2008 doi: 10.2746/095777308X356956
   Web of Science ®Google Scholar
• Scott EW, Armour J. Effect of development of resistance to benzimidazoles, salicylanilides and ivermectin on the pathogenicity and survival of Haemonchus contortus. The Veterinary Record 128, 346–9, 1991 doi: 10.1136/vr.128.15.346
   PubMed Web of Science ®Google Scholar
• Slocombe JOD, de Gannes RVG, Lake MC. Macrocyclic lactone-resistant Parascaris equorum on stud farms in Canada and effectiveness of fenbendazole and pyrantel pamoate. Veterinary Parasitology 145, 371–6, 2007 doi: 10.1016/j.vetpar.2006.08.008
   PubMed Web of Science ®Google Scholar
• Smith G, Grenfell BT, Isham V, Cornell S. Anthelmintic resistance revisited: under-dosing, chemoprophylactic strategies, and mating probabilities. International Journal for Parasitology 29, 77–91, 1999 doi: 10.1016/S0020-7519(98)00186-6
   PubMed Web of Science ®Google Scholar
• Stowers NL, Rogers CW, Hoskin SO. Management of weanlings on commercial Thoroughbred stud farms in the North Island of New Zealand. Proceedings of the New Zealand Society of Animal Production 69, 4–9, 2009
   Google Scholar
• Stratford CH, McGorum BC, Pickles KJ, Matthews JB. An update on cyathostomins: anthelmintic resistance and diagnostic tools. Equine Veterinary Journal 43 (Suppl. 39), 133–9, 2011 doi: 10.1111/j.2042-3306.2011.00397.x
   PubMed Web of Science ®Google Scholar
• Sutherland IA, Leathwick DM, Brown AE, Miller CM. Prophylactic efficacy of persistent anthelmintics against challenge with drug-resistant and susceptible Ostertagia circumcincta. Veterinary Record 141, 120–3, 1997 doi: 10.1136/vr.141.5.120
   PubMed Web of Science ®Google Scholar
• Szeto CC, Gillespie KM, Mathieson PW. Levamisole induces interleukin-18 and shifts type 1/type 2 cytokine balance. Immunology 100, 217–24, 2000 doi: 10.1046/j.1365-2567.2000.00042.x
   PubMed Web of Science ®Google Scholar
• Tandon R, Kaplan RM. Evaluation of a larval development assay (DrenchRite®) for the detection of anthelmintic resistance in cyathostomin nematodes of horses. Veterinary Parasitology 121, 125–42, 2004 doi: 10.1016/j.vetpar.2003.09.016
   PubMed Web of Science ®Google Scholar
• Toscan G, Cezar AS, Pereira RCF, Silva GB, Sangioni LA, Oliveira LSS, Vogel FSF. Comparative performance of macrocyclic lactones against large strongyles in horses. Parasitology International 61, 550–3, 2012 doi: 10.1016/j.parint.2012.05.001
   PubMed Web of Science ®Google Scholar
• Traversa D, Iorio R, Otranto D, Giangaspero A, Milillo P, Klei TR. Species-specific identification of equine cyathostomins resistant to fenbendazole and susceptible to oxibendazole and moxidectin by microarray probing. Experimental Parasitology 121, 92–5, 2009 doi: 10.1016/j.exppara.2008.10.001
   PubMed Web of Science ®Google Scholar
• Trotz-Williams L, Physick-Sheard P, McFarlane H, Pearl DL, Martin SW, Peregrine AS. Occurrence of Anoplocephala perfoliata infection in horses in Ontario, Canada and associations with colic and management practices. Veterinary Parasitology 153, 73–84, 2008 doi: 10.1016/j.vetpar.2008.01.016
   PubMed Web of Science ®Google Scholar
• Vidyashankar AN, Kaplan RM, Chan S. Statistical approach to measure the efficacy of anthelmintic treatment on horse farms. Parasitology 134, 2027–39, 2007 doi: 10.1017/S003118200700340X
   PubMed Web of Science ®Google Scholar
• Vidyashankar AN, Hanlon BM, Kaplan RM. Statistical and biological considerations in evaluating drug efficacy in equine strongyle parasites using fecal egg count data. Veterinary Parasitology 185, 45–56, 2012 doi: 10.1016/j.vetpar.2011.10.011
   PubMed Web of Science ®Google Scholar
• Wood ELD, Matthews JB, Stephenson S, Slote M, Nussey DH. Variation in faecal egg counts in horses managed for conservation purposes: individual egg shedding consistency, age effects and seasonal variation. Parasitology 140, 115–28, 2012 doi: 10.1017/S003118201200128X
   PubMed Web of Science ®Google Scholar
• Young KE, Garza V, Snowden K, Dobson RJ, Powell D, Craig TM. Parasite diversity and anthelmintic resistance in two herds of horses. Veterinary Parasitology 85, 205–14, 1999 doi: 10.1016/S0304-4017(99)00100-4
   PubMed Web of Science ®Google Scholar
• van Zeveren AM, Casaert S, Alvinerie M, Geldhof P, Claerebout E, Vercruysse J. Experimental selection for ivermectin resistance in Ostertagia ostertagi in cattle. Veterinary Parasitology 150, 104–10, 2007 doi: 10.1016/j.vetpar.2007.09.004
   PubMed Web of Science ®Google Scholar