Responsible use of antiparasitic medications in veterinary practice

Published 16 June 2023 | Updated 23 July 2025

Introduction

Antimicrobial resistance is considered to be a global public health problem. While we are now used to considering responsible use of antibiotics to minimise the development of antimicrobial resistance and protect the efficacy of these products for the treatment of bacterial infections in both humans and animals, we may be less used to thinking about responsible use in respect of anthelmintics (medications which treat helminth worm infections) and other parasiticides.

The World Health Organization defines antimicrobials – including antibiotics, antivirals, antifungals and antiparasitics – as medicines used to prevent and treat infections in humans, animals and plants.

The RCVS includes a requirement for veterinary surgeons to use anthelmintics responsibly in order to minimise resistance the  development of resistance to these products in Section 4 of the supporting guidance to the Code of Professional Conduct for Veterinary Surgeons.

However, we are now becoming aware that the responsible use of parasiticides extends beyond considerations of antimicrobial resistance and includes contamination of the environment and effects on the wider ecosystem.

The aim of this evidence collection will be to bring together a selection of the most relevant published evidence and other appropriate resources to enable veterinary surgeons to make responsible decisions in the use of antiparasitic medications in order to protect animal health and welfare, and in some cases human health, while minimising detrimental effects. This collection will not include details of the diagnosis and treatment of specific parasitic infections.

• Antimicrobial resistance (2021) [World Health Organization] [online]. Available from: https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance  [Accessed 8 June 2023]
• Code of Professional Conduct for Veterinary Surgeons. 4. Veterinary medicines [RCVS] [online]. Available from: https://www.rcvs.org.uk/setting-standards/advice-and-guidance/code-of-professional-conduct-for-veterinary-surgeons/supporting-guidance/veterinary-medicines/  [Accessed 8 June 2023]

Responsible use of antiparasitic medications – a one health issue

In order to use anthelmintics and antiparasitic medications responsibly it is important to consider not only the impact on the animals that we are treating but the potential impacts that these products may have on the wider environment. It is also important to be aware that some of the parasites that we treat in animals have zoonotic potential and therefore to consider the impact of failing to treat animals may have on human health.

Protecting human health

• Batchelor, D.J. et al. (2008) Detection of endoparasites with zoonotic potential in dogs with gastrointestinal disease in the UK. Transboundary and Emerging Diseases, 55 (2), pp. 99-104. https://doi.org/10.1111/j.1865-1682.2007.01005.x
• Drake, J. et al. (2022) Detection of Giardia and helminths in Western Europe at local K9 (canine) sites (DOGWALKS Study). Parasites & Vectors, 15, no. 311. https://doi.org/10.1186/s13071-022-05440-2

Toxocariasis

• Patterson, J. (2023) Toxocarosis in humans: how much of a problem is it in the UK? Drug and Therapeutics Bulletin, 61 (1), pp. 7-11. https://doi.org/10.1136/dtb.2022.000052
• Tarr, A. (2023) Toxocarosis: a One Health issue. Drug and Therapeutics Bulletin, 61 (1), p. 3. https://doi.org/10.1136/dtb.2022.000072 
• Halsby, K. et al. (2016) Epidemiology of toxocariasis in England and Wales. Zoonoses and Public Health, 63 (7), pp. 529-533. https://doi.org/10.1111/zph.12259
• Nijsse, R. et al. (2015) Environmental contamination with Toxocara eggs: a quantitative approach to estimate the relative contributions of dogs, cats and foxes, and to assess the efficacy of advised interventions in dogs. Parasites & Vectors, 8, no. 397. https://doi.org/10.1186/s13071-015-1009-9
• Airs, P.M. et al. (2023) WormWatch: Park soil surveillance reveals extensive Toxocara contamination across the UK and Ireland. Veterinary Record, 192 (1), p. e2341. https://doi.org/10.1002/vetr.2341
• Kaul, P., Wright, I. and Elsheikha, H. (2022) Soil contamination with Toxocara eggs in public parks in the Midlands. The Veterinary Nurse, 13 (8), pp. 383-391
• Healy, S.R. et al. (2022) First report demonstrating the presence of Toxocara eggs on vegetables grown in community gardens in Europe. Food and Waterborne Parasitology, 27, p. e00158. https://doi.org/10.1016/j.fawpar.2022.e00158

Echinococcus multilocularis

• Fisher, M. (2014) Update on Echinococcus multilocularis: with particular emphasis on its impact on humans. Companion Animal, 19 (5), pp. 232-235. https://doi.org/10.12968/coan.2014.19.5.232
• Gottstein, B. et al. (2015) Threat of alveolar echinococcosis to public health–a challenge for Europe. Trends in Parasitology, 31 (9), pp. 407-412. https://doi.org/10.1016/j.pt.2015.06.001
• Cenni, L. et al. (2023) Current and future distribution of a parasite with complex life cycle under global change scenarios: Echinococcus multilocularis in Europe. Global Change Biology. 29, pp. 2436-2449. https://doi.org/10.1111/gcb.16616
• European Food Safety Authority (EFSA) and Zancanaro, G. (2021) Annual assessment of Echinococcus multilocularis surveillance reports submitted in 2020 in the context of Commission Delegated Regulation (EU) 2018/772. EFSA Journal, 19 (1), p. e06382. https://doi.org/10.2903/j.efsa.2021.6382

Protecting the environment

There have been concerns about the effect of the use of parasiticides on the wider environment for some time. Initially the main concerns related to the use of neonicotinoids for pest control in plants and the effect that this was having on bees and other insects. There is already a wide literature base available regarding the impact of pharmaceuticals on the environment with many of these papers being published in journals that cover toxicology and environmental science. See the In The Spotlight: Veterinary medicines and the environment .

The following are a selection of papers, reports, and resources, specifically related to anthelmintics and other antiparasitic medications.

• De Marchi, L. et. al. (2025) Environmental risks and toxicity of fipronil and imidacloprid used in pets ectoparasiticides. Animals, 15 (11), no. 1533. https://doi.org/10.3390/ani15111533
• Perkins, R., Glauser, G., and Goulson, D. (2025) Swimming emissions from dogs treated with spot‐on fipronil or imidacloprid: Assessing the environmental risk. Veterinary Record, 196 (11), no. e5560. https://doi.org/10.1002/vetr.5560
• Yoder, L.E. et al. (2024) Dog swimming and ectoparasiticide water contamination in urban conservation areas: A case study on Hampstead Heath, London. Science of the Total Environment, 955, 176686. https://doi.org/10.1016/j.scitotenv.2024.176686
• Rasmussen, S.L. et al. (2024) Pesticides in the population of European hedgehogs (Erinaceus europaeus) in Denmark. Frontiers in Veterinary Science, 11. https://doi.org/10.3389/fvets.2024.1436965
• Berny, P.J. et al. (2024) Fecal elimination of fluralaner in different carnivore species after oral administration. Frontiers in Veterinary Science, 11. https://doi.org/10.3389/fvets.2024.1279844
• Haseler, C.J. et al. (2024) Environmental impacts of equine parasiticide treatment: The UK perspective. Equine Veterinary Education, https://doi.org/10.1111/eve.13944
• Rondeau, G. et al. (2014) Delayed and time-cumulative toxicity of imidacloprid in bees, ants and termites. Scientific Reports, 4, no. 5566. https://doi.org/10.1038/srep05566
• Forbes, A. (2021) Environmental risk assessment of veterinary parasiticides used in cattle. Livestock, 26 (1), pp. 15-25. https://doi.org/10.12968/live.2021.26.1.15
• Paleolog, J. et al. (2023) Imidacloprid pesticide causes unexpectedly severe bioelement deficiencies and imbalance in honey bees even at sublethal doses. Animals, 13 (4), no. 615. https://doi.org/10.3390/ani13040615
• Wells, C. and Collins, C.M.T. (2022) A rapid evidence assessment of the potential risk to the environment presented by active ingredients in the UK’s most commonly sold companion animal parasiticides. Environmental Science and Pollution Research, 29, pp. 45070-45088. https://doi.org/10.1007/s11356-022-20204-2
• Perkins, R. et al. (2024) Down-the-drain pathways for fipronil and imidacloprid applied as spot-on parasiticides to dogs: Estimating aquatic pollution. Science of The Total Environment, 917, 170175. https://doi.org/10.1016/j.scitotenv.2024.170175.
• Perkins, R. et al. (2021) Potential role of veterinary flea products in widespread pesticide contamination of English rivers. Science of The Total Environment, 755 (1), no. 143560. https://doi.org/10.1016/j.scitotenv.2020.143560
• Preston-Allen, R.G.G. et al. (2023) Grantham Institute Briefing. Are urban areas hotspots for pollution from pet parasiticides? [Imperial College] [online]. Available from: https://www.imperial.ac.uk/grantham/publications/are-urban-areas-hotspots-for-pollution-from-pet-parasiticides.php [Accessed 8 June 2023]
• Food safety. Some facts about neonicotinoids [European Commission] [online]. Available from: https://food.ec.europa.eu/plants/pesticides/approval-active-substances/renewal-approval/neonicotinoids_en [Accessed 8 June 2023]

Lack of efficacy and resistance

How well antiparasitic products work in practice may depend on a number of factors relating to the appropriate use at the right time in the life cycle of the parasite. It is important to be aware that not all treatment failure relates to the development of resistance to the product.

• Geurden, T. et al. (2022) World Association for the Advancement of Veterinary Parasitology (WAAVP) guideline for the evaluation of the efficacy of anthelmintics in food-producing and companion animals: general guidelines. Veterinary Parasitology, 304, p. 109698. https://doi.org/10.1016/j.vetpar.2022.109698
• Marchiondo, A.A. et al. (2013) World Association for the Advancement of Veterinary Parasitology (WAAVP) second edition: guidelines for evaluating the efficacy of parasiticides for the treatment, prevention and control of flea and tick infestations on dogs and cats. Veterinary Parasitology, 194 (1), pp. 84-97. https://doi.org/10.1016/j.vetpar.2013.02.003
• Otranto, D. et al. (2021) World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines for studies evaluating the efficacy of parasiticides in reducing the risk of vector-borne pathogen transmission in dogs and cats. Veterinary Parasitology, 290, p. 109369. https://doi.org/10.1016/j.vetpar.2021.109369
• Beugnet, F. et al. (2022) World Association for the Advancement of Veterinary Parasitology (WAAVP): Second edition of guidelines for evaluating the efficacy of anthelmintics for dogs and cats. Veterinary Parasitology, 312, p. 109815. https://doi.org/10.1016/j.vetpar.2022.109815
• Kaplan, R.M. et al. (2023) World Association for the Advancement of Veterinary Parasitology (WAAVP) guideline for diagnosing anthelmintic resistance using the faecal egg count reduction test in ruminants, horses and swine. Veterinary Parasitology, 318, p. 109936. https://doi.org/10.1016/j.vetpar.2023.109936
• Other guidelines from WAAVP are available from: Antiparasitic guidelines [WAAVP] [online]. Available from: https://www.waavp.org/antiparasitic-guidelines/published-guidelines.html [Accessed 8 June 2023]
• McNair, C.M. (2015) Ectoparasites of medical and veterinary importance: drug resistance and the need for alternative control methods. Journal of Pharmacy and Pharmacology, 67 (3), pp.351-36. https://doi.org/10.1111/jphp.12368
• Kaplan, R.M. (2004) Drug resistance in nematodes of veterinary importance: a status report. Trends in Parasitology, 20 (10), pp.477-481. https://doi.org/10.1016/j.pt.2004.08.001
• Morgan, E.R. et al. (2022) Confounding factors affecting faecal egg count reduction as a measure of anthelmintic efficacy. Parasite, 29, no. 20. https://doi.org/10.1051%2Fparasite%2F2022017
• Denwood, M.J. et al. (2023) A statistical framework for calculating prospective sample sizes and classifying efficacy results for faecal egg count reduction tests in ruminants, horses and swine. Veterinary Parasitology, 314, p.109867. https://doi.org/10.1016/j.vetpar.2022.109867

Farm animal

• Hennessey, M. et al. (2020) Antimicrobial & antiparasitic use and resistance in British sheep and cattle: a systematic review. Preventive Veterinary Medicine, 185, p.105174. https://doi.org/10.1016/j.prevetmed.2020.105174
  A journal watch summary of this article is available.
• Rose, H. et al. (2015) Widespread anthelmintic resistance in European farmed ruminants: a systematic review. Veterinary Record, 176 (21), pp. 546. https://doi.org/10.1136/vr.102982
• Rose Vineer, H. et al. (2020) Increasing importance of anthelmintic resistance in European livestock: creation and meta-analysis of an open database. Parasite, 27, no. 69. https://doi.org/10.1051/parasite/2020062
• Kaplan, R.M. (2020) Biology, epidemiology, diagnosis, and management of anthelmintic resistance in gastrointestinal nematodes of livestock. Veterinary Clinics: Food Animal Practice, 36 (1), pp. 17-30. https://doi.org/10.1016/j.cvfa.2019.12.001
• Special issue: Ruminant Parasitology (2022) Veterinary Clinics: Food Animal Practice, 36 (1)
• Kotze, A.C. and Hunt, P.W. (2023) The current status and outlook for insecticide, acaricide and anthelmintic resistances across the Australian ruminant livestock industries: assessing the threat these resistances pose to the livestock sector. Australian Veterinary Journal, 101 (9), pp. 321-333. https://doi.org/10.1111/avj.13267
• Kelleher, A.C. et al. (2020) Anthelmintic resistance among gastrointestinal nematodes of cattle on dairy calf to beef farms in Ireland. Irish Veterinary Journal, 73, no. 12. https://irishvetjournal.biomedcentral.com/articles/10.1186/s13620-020-00167-x
• Falzon, L.C. et al. (2014) A systematic review and meta-analysis of factors associated with anthelmintic resistance in sheep. Preventive Veterinary Medicine, 117 (2), pp. 388-402. https://doi.org/10.1016/j.prevetmed.2014.07.003
• Baudinette, E., O’Handley, R. and Trengove, C. (2022) Anthelmintic resistance of gastrointestinal nematodes in goats: A systematic review and meta-analysis. Veterinary Parasitology, 312, p. 109809. https://doi.org/10.1016/j.vetpar.2022.109809
• Taylor, M.A. et al. (2009) Multiple resistance to anthelmintics in sheep nematodes and comparison of methods used for their detection. Small Ruminant Research, 86 (1-3), pp. 67-70. https://doi.org/10.1016/j.smallrumres.2009.09.020
• Bull, K. et al. (2022) Increasing resistance to multiple anthelmintic classes in gastrointestinal nematodes on sheep farms in southwest England. Veterinary Record, 190 (11), p. e1531. https://doi.org/10.1002/vetr.1531
• Hamer, K. et al. (2018) Lack of efficacy of monepantel against trichostrongyle nematodes in a UK sheep flock. Veterinary Parasitology, 257, pp. 48- 53 https://doi.org/10.1016/j.vetpar.2018.05.013
  A journal watch summary of this article is available.
• Van den Brom, R. et al. (2013) Multiple anthelmintic resistance of Haemonchus contortus, including a case of moxidectin resistance, in a Dutch sheep flock. Veterinary Record, 173 (22), p. 552. https://doi.org/10.1136/vr.101700
• Busin, V. (2018) Treatment of sheep scab in the UK: preventing the spread of resistant mites. Veterinary Record, 182 (4), pp. 104-105. https://doi.org/10.1136/vr.k422

Equine

• Elghryani, N. et al. (2024) Unravelling the effectiveness of anthelmintic treatments on equine strongyles on Irish farms. Animals, 14 (13), no. 1958. https://doi.org/10.3390/ani14131958
• Finnerty, C.A. et al. (2024) Evidence of tapeworm treatment failure on a Central Kentucky Thoroughbred farm. Equine Veterinary Education https://doi.org/10.1111/eve.13950
• Tzelos, T. and Matthews, J. (2016) Anthelmintic resistance in equine helminths and mitigating its effects. In Practice, 38 (10), pp. 489-499. https://doi.org/10.1136/inp.i5287
• Matthews, J.B. (2014) Anthelmintic resistance in equine nematodes. International Journal for Parasitology: Drugs and Drug Resistance, 4 (3), pp. 310-315. https://doi.org/10.1016/j.ijpddr.2014.10.003
• Nielsen, M.K. et al. (2014) Anthelmintic resistance in equine parasites—Current evidence and knowledge gaps. Veterinary Parasitology, 204 (1-2), pp. 55-63. https://doi.org/10.1016/j.vetpar.2013.11.030
• Wallace, J.D.G. (2022) Equine endoparasite resistance and its management–a vet practice perspective. Veterinary Record, 191 (11), p. e2512. https://doi.org/10.1002/vetr.2512
• Rendle, D. et al. (2021) Anthelmintic resistance in equids.  Veterinary record, 188 (6), pp. 230-231. https://doi.org/10.1002/vetr.332

Small animal

• Geary, T.G. et al. (2025) Multiple anthelmintic drug resistance in the canine hookworm Ancylostoma caninum: AAVP position paper and research needs. Veterinary Parasitology, 338, no. 110536. https://doi.org/10.1016/j.vetpar.2025.110536
• Nind, F. et al. (2020) Antiparasitic resistance. In: Nind, F. and Mosedale, P. (eds.) BSAVA Guide to the use of veterinary medicines. Quedgeley, BSAVA, pp. 92-94. Available from:  https://www.bsavalibrary.com/content/chapter/10.22233/9781905319862.chap20 [Accessed 8 June 2023]
• Coles, T.B. and Dryden, M.W. (2014) Insecticide/acaricide resistance in fleas and ticks infesting dogs and cats. Parasites & Vectors, 7 (1), no. 8. https://doi.org/10.1186/1756-3305-7-8
• Rust, M.K. (2016) Insecticide resistance in fleas. Insects, 7 (1), no. 10. https://doi.org/10.3390/insects7010010
• Elsheikha, H., Wong, S. and Wright, I. (2021) Flea infestation: a snapshot on the common products and the reasons for treatment failure. The Veterinary Nurse, 12 (2), pp. 58-65. https://doi.org/10.12968/vetn.2021.12.2.58
• Wong, S., Elsheikha, H. and Dryden, M. (2021) Flea product efficacy, pet owners’ adherence and treatment failure: what’s the connection? Companion Animal, 26 (8), pp. 182-190. https://doi.org/10.12968/coan.2021.0006
• Jimenez Castro, P.D. et al. (2019) Multiple drug resistance in the canine hookworm Ancylostoma caninum: an emerging threat? Parasites & Vectors, 12 (1), no. 576. https://doi.org/10.1186/s13071-019-3828-6
• Jimenez Castro, P.D. et al. (2023) Multiple anthelmintic drug resistance in hookworms (Ancylostoma caninum) in a Labrador breeding and training kennel in Georgia, USA. Journal of the American Veterinary Medical Association, 261 (3), pp. 342-347. https://doi.org/10.2460/javma.22.08.0377
• von Samson-Himmelstjerna, G. et al. (2021) Spread of anthelmintic resistance in intestinal helminths of dogs and cats is currently less pronounced than in ruminants and horses–Yet it is of major concern. International Journal for Parasitology: Drugs and Drug Resistance, 17, pp. 36-45. https://doi.org/10.1016/j.ijpddr.2021.07.003
• Ciuca, L. et al. (2021) Effectiveness of fenbendazole and metronidazole against Giardia infection in dogs monitored for 50-days in home-conditions. Frontiers in Veterinary Science, 8, no. 626424. https://doi.org/10.3389/fvets.2021.626424
• Evason, M.D. et al. (2023) Emergence of canine hookworm treatment resistance: Novel detection of Ancylostoma caninum anthelmintic resistance markers by fecal PCR in 11 dogs from Canada. American Journal of Veterinary Research,  84 (9). https://doi.org/10.2460/ajvr.23.05.0116
• Nezami, R., Blanchard, J. and Godoy, P. (2023) The canine hookworm Ancylostoma caninum: A novel threat for anthelmintic resistance in Canada. Canadian Veterinary Journal, 64 (4), pp. 372-378. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10031793/

Guidelines and recommendations for responsible use

Farm animals

• BVA (2017) Policy statement. Anthelmintic resistance and responsible use in livestock [BVA] [online]. Available from: https://www.bva.co.uk/media/1169/anthelmintic-resistance-and-responsible-use-in-livestock.pdf [Accessed 8 June 2023]
• EPRUMA (2018) Best Practice Framework on the use of anthelmintics in food-producing animals [EPRUMA] [online]. Available from: https://epruma.eu/home/best-practice-guides/best-practice-framework-on-the-use-of-anthelmintics-in-food-producing-animals/ [Accessed 6 June 2023]
• Responsible use of anthelmintics in grazing animals [RUMA] [online]. Available from: https://www.ruma.org.uk/responsible-use-of-anthelminitics-in-grazing-animals/ [Accessed 6 June 2023]
• Helping sheep farmers to maximise productivity by sustainably controlling parasites [SCOPS] [online]. Available from: https://www.scops.org.uk/ [Accessed 6 June 2023]
• SCOPS internal parasite technical manual [SCOPS] [online]. Available from: https://www.scops.org.uk/advisers-technical-info/ [Accessed 6 June 2023]
• SCOPS ‘Know your anthelmintic guide’ [SCOPS] [online]. Available from https://www.scops.org.uk/about/scops-know-your-anthelmintics-guide/ [Accessed 6 June 2023]
• Control of worms sustainably [COWS] [online]. Available from: https://www.cattleparasites.org.uk/ [Accessed 6 June 2023]
• Sargison, N. (2011) Responsible use of anthelmintics for nematode control in sheep and cattle. In Practice, 33 (7), pp. 318-327. https://doi.org/10.1136/inp.d4504
• Morgan, E.R. et al. (2023) Anthelmintic treatment and the stability of parasite distribution in ruminants. Animals, 13 (11), 1882. https://doi.org/10.3390/ani13111882
• Charlier, J. et al. (2014) Practices to optimise gastrointestinal nematode control on sheep, goat and cattle farms in Europe using targeted (selective) treatments. Veterinary Record, 175 (10), pp. 250-255. https://doi.org/10.1136/vr.102512
• Howe, R. (2023) Parasite control in cattle is evolving. Livestock, 28 (5), PP. 196-198. https://doi.org/10.12968/live.2023.28.5.196
• Learmount, J. et al. (2015) Evaluation of ‘best practice’ (SCOPS) guidelines for nematode control on commercial sheep farms in England and Wales. Veterinary Parasitology, 207 (3-4), pp. 259-265. https://doi.org/10.1016/j.vetpar.2014.12.004
• Learmount, J. et al. (2016) Three-year evaluation of best practice guidelines for nematode control on commercial sheep farms in the UK. Veterinary Parasitology, 226, pp. 116-123. https://doi.org/10.1016/j.vetpar.2016.06.037
• Learmount, J., Glover, M.J. and Taylor, M.A. (2018) Resistance delaying strategies on UK sheep farms: a cost benefit analysis. Veterinary Parasitology, 254, pp. 64-71. https://doi.org/10.1016/j.vetpar.2018.02.033
• McIntyre, J. et al. (2023) Moxidectin use in Scottish sheep flocks suggests a need for clearer product labelling and communication of updated SCOPS guidelines. Veterinary Record, 192 (2), p. e2083. https://doi.org/10.1002/vetr.2083
• Gascoigne, E. et al. (2018) Controlling nematode infections in sheep: application of HACCP. In Practice, 40 (8), pp. 334-347. https://doi.org/10.1136/inp.k3858
• Sautier, M. and Chiron, P. (2023) Challenges and opportunities for reducing anthelmintic use in ruminant livestock systems: insights from a sheep farmer survey in France. Preventive Veterinary Medicine, 221, no. 106078. https://doi.org/10.1016/j.prevetmed.2023.106078
• Sauermann, C., et al. (2023) Simultaneous resistance to multiple anthelmintic classes in nematode parasites of cattle in New Zealand. Veterinary Parasitology, 325, no. 110079. https://doi.org/10.1016/j.vetpar.2023.110079

Equine

• Hedberg, A.Y. et al. (2024) Farm size and biosecurity measures associated with Strongylus vulgaris infection in horses. Equine Veterinary Journal. https://doi.org/10.1111/evj.14212
• Rendle, D. et al. (2024) BEVA primary care clinical guidelines: Equine parasite control. Equine Veterinary Journal, 56 (3), pp. 392-423. https://doi.org/10.1111/evj.14036
• ESCCAP (2019) Guidelines GL8: A guide to the treatment and control of equine gastrointestinal parasite infections [ESCCAP] [online]. Available from https://www.esccap.org/guidelines/gl8/ [Accessed 6 June 2023]
• Anthelmintic stewardship and sustainability – A call to arms (2021) [BEVA] [online]. Available from: https://www.beva.org.uk/Home/News-and-Views/Latest-News/Details/Anthelmintic-Stewardship-and-Sustainability–A-Call-to-Arms [Accessed 6 June 2023]
• Parasitic roundworms (equine) [Moredun] [online]. Available from: https://moredun.org.uk/research/diseases/parasitic-roundworms-equine [Accessed 6 June 2023]
• Matthews, J.B. and Austin, C.J. (2023) Using diagnostics in supporting sustainable worm control in horses. UK-Vet Equine, 7 (6), pp. 231-236. https://doi.org/10.12968/ukve.2023.7.6.231
• Madders, G. (2023) Think before you worm: A new campaign to tackle resistance. UK-Vet Equine, 7 (5), pp. 192-194. https://doi.org/10.12968/ukve.2023.7.5.192
• Abbas, G. et al. (2023) Assessment of worm control practices recommended by equine veterinarians in Australia. Frontiers in Veterinary Science, 10, no. 1305360.  https://doi.org/10.3389/fvets.2023.1305360
• Hedberg Alm, Y. et al. (2023) Retained efficacy of ivermectin against cyathostomins in Swedish horse establishments practicing selective anthelmintic treatment. Veterinary Parasitology, 322, 110007 https://doi.org/10.1016/j.vetpar.2023.110007

Companion animals

• British Veterinary Association, British Small Animal Veterinary Association and British Veterinary Zoological Society (2022) Responsible use of parasiticides for cats and dogs: The five point plan [BVA] [online]. Available from: https://www.bva.co.uk/resources-support/medicines/responsible-use-of-parasiticides-for-cats-and-dogs-the-five-point-plan/ [Accessed 31 January 2025]
• Wright, I. (2024) Routine screening and clinical diagnosis of intestinal helminths in cats and dogs. Companion Animal. 29:10, pp.2-5. https://doi.org/10.12968/coan.2024.0004
• Shotton, J. (2024) Parasiticides in dogs and cats: a risk-based approach. The Veterinary Nurse, 15 (40), pp. 138-140. https://doi.org/10.12968/vetn.2024.0024
• ESCCAP (2021) Guidelines GL1: Worm control in dogs and cats [ESCCAP] [online]. Available from: https://www.esccap.org/guidelines/gl1/ [Accessed 6 June 2023]
• ESCCAP (2022) Guidelines GL3: Control of ectoparasites in dogs and cats [ESCCAP] [online]. Available from: https://www.esccap.org/guidelines/gl3/ [Accessed 6 June 2023]
• ESCCAP (2023) Guidelines GL5: Control of vector-borne diseases in dogs and cats [ESCCAP] [online]. Available from: https://www.esccap.org/guidelines/gl5/ [Accessed 6 June 2023]
• ESCCAP (2018) Guidelines GL6: Control of intestinal protozoa in dogs and cats [ESCCAP] [online]. Available from: https://www.esccap.org/guidelines/gl6/ [Accessed 6 June 2023]
• ESCCAP (2017) Guidelines GL7: Parasites and fungal infections in small pet mammals [ESCCAP] [online]. Available from: https://www.esccap.org/guidelines/gl7/ [Accessed 6 June 2023]
• Mulcahy, G. (2024) Is it time to re-evaluate anti-parasitic use in companion animals? Companion Animal, 29 (3), pp. 12-18.
  https://doi.org/10.12968/coan.2023.0067
• Vrhovec, M.G. et al. (2022) Is there any change in the prevalence of intestinal or cardiopulmonary parasite infections in companion animals (dogs and cats) in Germany between 2004-2006 and 2015-2017? An assessment of the impact of the first ESCCAP guidelines. Veterinary Parasitology, 312, p. 109836. https://doi.org/10.1016/j.vetpar.2022.109836

Owner perceptions

When looking at the decision making regarding the use of anthelmintics and other antiparasitic medications in the treatment of animals, it is important to acknowledge the involvement and effect of the animal owner on the decision-making process. This is particularly important as some of these medications are available without prescription.

Farm animal

• Jack, C. et al. (2017) A quantitative analysis of attitudes and behaviours concerning sustainable parasite control practices from Scottish sheep farmers. Preventive Veterinary Medicine, 139 (Part B), pp. 134-145. https://doi.org/10.1016/j.prevetmed.2017.01.018
• Jack, C. et al. (2022) Determining the influence of socio-psychological factors on the adoption of individual ‘best practice’ parasite control behaviours from Scottish sheep farmers. Preventive Veterinary Medicine, 200, p. 105594. https://doi.org/10.1016/j.prevetmed.2022.105594
• Moore, H., Pandolfi, F. and Kyriazakis, I. (2016) Familiarity with and uptake of alternative methods to control sheep gastro-intestinal parasites on farms in England. Veterinary Parasitology, 221, pp. 1-8. https://doi.org/10.1016/j.vetpar.2016.03.002
• Morgan, E.R. (2012) A survey of helminth control practices on sheep farms in Great Britain and Ireland. The Veterinary Journal, 192 (3), pp. 390-397. https://doi.org/10.1016/j.tvjl.2011.08.004

Equine

• Shrubb, J. et. al. (2025) Project WORMS (working to overcome resistance and make for a sustainable future): Horse owner survey of equine parasite control. Part 2. Anthelmintic use. Equine Veterinary Education. https://doi.org/10.1111/eve.14116
• Shrubb, J. et. al. (2025) Project WORMS (working to overcome resistance and make for a sustainable future): Horse owner survey on equine parasite control in the UK. Part 1. Management factors. Equine Veterinary Education. https://doi.org/10.1111/eve.14112
• McTigue, F.E., Mansbridge, S.C. and Pyatt, A.Z. (2022) Equine anthelmintic resistance: Horse owner and yard manager perception of the barriers affecting strategic control measures in England. Veterinary Sciences, 9 (10), no. 560. https://doi.org/10.3390/vetsci9100560
• Furtado, T. and Rendle, D. (2021) Creating environments for change: are there new ways to approach horse keeper behaviour in equine parasite control? Veterinary Record, 189 (5), pp. 197-199. https://doi.org/10.1002/vetr.906
• Easton, S. et al. (2016) Investigating interactions between UK horse owners and prescribers of anthelmintics. Preventive Veterinary Medicine, 135, pp. 17-27. https://doi.org/10.1016/j.prevetmed.2016.10.017
• Tzelos, T. et al. (2019) A survey of the level of horse owner uptake of evidence-based anthelmintic treatment protocols for equine helminth control in the UK. Veterinary Parasitology, 274, p. 108926. https://doi.org/10.1016/j.vetpar.2019.108926
• Allison, K. et al. (2011) Equine anthelmintics: survey of the patterns of use, beliefs and attitudes among horse owners in the UK. Veterinary Record, 168 (18), p. 483. https://doi.org/10.1136/vr.d731

Small animal

• McNamara, J. et al. (2018) Survey of European pet owners quantifying endoparasitic infection risk and implications for deworming recommendations. Parasites & Vectors, 11 (1), no. 571. https://doi.org/10.1186/s13071-018-3149-1
• Bebrysz, M. et al. (2021) How pet owners choose antiparasitic treatments for their dogs: A discrete choice experiment. Preventive Veterinary Medicine, 196, p. 105493. https://doi.org/10.1016/j.prevetmed.2021.105493
• Lavan, R.P. et al. (2017) Assessment of dog owner adherence to veterinarians’ flea and tick prevention recommendations in the United States using a cross-sectional survey. Parasites & Vectors, 10 (1), no. 284. https://doi.org/10.1186/s13071-017-2217-2
• Pennelegion, C. et al. (2020) Survey of UK pet owners quantifying internal parasite infection risk and deworming recommendation implications. Parasites & Vectors, 13, no. 218. https://doi.org/10.1186/s13071-020-04086-2

Exotic and imported disease

The responsible use of antiparasitic medications requires an understanding of the parasitic diseases that need to be prevented, controlled or treated. Animals which have been imported or travelled abroad may be exposed to diseases which are not endemic in the UK, and climate change may affect the spread of vectors and therefore the potential for parasitic disease to spread. The following resources may be useful when considering possible exposure to exotic and imported diseases.

• Equine exotic diseases [BEVA] [online]. Available from: https://www.beva.org.uk/Guidance-and-Resources/Infectious-Diseases/Equine-Exotic-Disease [Accessed 6 June 2023]
• Guideline maps [ESCCAP] [online]. Available from: https://www.esccap.org/guidelines-maps/ [Accessed 6 June 2023]
• Surveillance and disease data for disease vectors [European Centre for Disease Prevention and Control] [online] Available from: https://www.ecdc.europa.eu/en/disease-vectors/surveillance-and-disease-data [Accessed 6 June 2023]
• Weekly updates: 2022 West Nile virus transmission season [European Centre for Disease Prevention and Control] [online]. Available from: https://www.ecdc.europa.eu/en/west-nile-fever/surveillance-and-disease-data/disease-data-ecdc [Accessed 6 June 2023]
• New Heartworm Incidence Map shows increase in parasitic cases [dvm360] [online]. Available from: https://www.dvm360.com/view/new-heartworm-incidence-map-shows-increase-in-parasitic-cases? [Accessed 6 June 2023]
• Animal diseases [World Organisation for Animal Health] [online] Available from: https://www.woah.org/en/what-we-do/animal-health-and-welfare/animal-diseases/ [Accessed 6 June 2023]
• Fisher, M.A. et al. (2023) A survey of gastrointestinal parasites in dogs illegally entering the UK (2015–2017). Veterinary Record Open, 10 (1), p. e54. https://doi.org/10.1002/vro2.54
• Panarese, R. et al. (2023) The long-distance relationship between Dirofilaria and the UK: case report and literature review. Frontiers in Veterinary Science, 10, https://doi.org/10.3389/fvets.2023.1128188

About evidence collections

Evidence collections bring together collections of published papers on topics of interest and importance to the veterinary professions. Papers are chosen for relevance and accessibility, with the full text of articles either being available through the RCVS Knowledge library, on open access or from other publications to which a significant number of veterinary professionals are likely to have access. This means that there may be relevant evidence that is not included.

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