Canadian Parasitology Expert Panel. Guidelines for the Management of Parasites in dogs and cats. 2019. https// (accessed 2 October 2023)

Companion Animal Parasite Council. Intestinal Parasite Guidelines. 2023. https// (last accessed 2 October 2023)

Davidson RK, Øines Ø, Hamnes IS, Schulze JE. Illegal wildlife imports more than just animals – Baylisascaris procyonis in raccoons (Procyon lotor) in Norway. J Wildl Dis. 2013; 49:(4)986-990

Drake J, Sweet S, Baxendale K Detection of Giardia and helminths in Western Europe at local K9 (canine) sites (DOGWALKS Study). Parasit Vectors. 2022; 15:(1)

European Scientific Counsel Companion Animal Parasites (ESCCAP). Worm control in dogs and cats. 2023. https// (accessed 2 October 2023)

Evason MD, Jenkins EJ, Kolapo TU, Mitchell KD, Leutenegger CM, Peregrine AS. Novel molecular diagnostic (PCR) diagnosis and outcome of intestinal Echinococcus multilocularis in a dog from western Canada. J Am Vet Med Assoc. 2023a; 261:(9)1-3

Evason MD, Weese JS, Polansky B, Leutenegger CM. Emergence of canine hookworm treatment resistance: Novel detection of Ancylostoma caninum anthelmintic resistance markers by fecal PCR in 11 dogs from Canada. Am J Vet Res. 2023b; 84:(9)

Fisher MA, Rees B, Capner C, Pritchard S, Holdsworth PA, Fitzgerald RA. A survey of gastrointestinal parasites in dogs illegally entering the UK (2015–2017). Vet Rec Open. 2023; 10:(1)

French SK, Pearl DL, Peregrine AS, Jardine CM. Baylisascaris procyonis infection in raccoons: a review of demographic and environmental factors influencing parasite carriage. Vet Parasitol Reg Stud Reports. 2019; 16

Gavin PJ, Kazacos KR, Shulman ST. Baylisascariasis. Clin Microbiol Rev. 2005; 18:(4)703-718

Idika IK, Ezeudu TA, Eze UU In vivo and in vitro efficacy of Albendazole against canine ancylostomosis: a possible presence of anthelmintic resistance in Nigerian local breed of dogs. Res J Parasitol. 2016; 11:(1–2)20-26

Jimenez Castro PD, Howell SB, Schaefer JJ, Avramenko RW, Gilleard JS, Kaplan RM. Multiple drug resistance in the canine hookworm Ancylostoma caninum: an emerging threat?. Parasit Vectors. 2019; 12:(1)

Jimenez Castro PD, Venkatesan A, Redman E Multiple drug resistance in hookworms infecting greyhound dogs in the USA. Int J Parasitol Drugs Drug Resist. 2021; 17:107-117

Jimenez Castro PD, Durrence K, Durrence S Multiple anthelmintic drug resistance in hookworms (Ancylostoma caninum) in a Labrador breeding and training kennel in Georgia, USA. J Am Vet Med Assoc. 2022; 261:(3)342-347

Kolapo TU, Hay A, Gesy KM Canine Alveolar Echinococcosis: an emerging and costly introduced problem in North America. Trans and Emerg Dis. 2023; 2023:1-10

Leutenegger CM, Lozoya CE, Tereski J, Savard C, Ogeer J, Lallier R. Emergence of Ancylostoma caninum parasites with the benzimidazole resistance F167Y polymorphism in the US dog population. Int J Parasitol Drugs Drug Resist. 2023; 21:131-140

Marsh AE, Babcock S. Legal implications of zoonotic disease transmission for veterinary practices. Vet Clin North Am Small Anim Pract. 2015; 45:(2)393-vii

Marsh AE, Lakritz J. Reflecting on the past and fast forwarding to present day anthelmintic resistant Ancylostoma caninum – a critical issue we neglected to forecast. Int J Parasitol Drugs Drug Resist. 2023; 22:36-43

Nezami R, Blanchard J, Godoy P. The canine hookworm Ancylostoma caninum: A novel threat for anthelmintic resistance in Canada. Can Vet J. 2023; 64:(4)372-378

Tropical Council for Companion Animal Parasites (TroCCAP). Canine guidelines. 2023. https// (accesed 2 October 2023)

Venkatesan A, Jimenez Castro PD, Morosetti A Molecular evidence of widespread benzimidazole drug resistance in Ancylostoma caninum from domestic dogs throughout the USA and discovery of a novel β-tubulin benzimidazole resistance mutation. PLoS Pathog. 2023; 19:(3)

Weese S, Evason M. Infectious diseases of the dog and cat - a color handbook.Boca Raton: CRC Press; 2019

Updates on emerging and evolving gastrointestinal parasites in dogs and cats

02 November 2023
9 mins read
Volume 14 · Issue 9
Figure 1. Life cycle of canine hookworm, Ancylostoma caninum (image reproduced with permission of MARS Pet Care/Antech Diagnostics, Education).
Figure 1. Life cycle of canine hookworm, Ancylostoma caninum (image reproduced with permission of MARS Pet Care/Antech Diagnostics, Education).


Gastrointestinal parasites are a common veterinary concern and pet owner conversation. Globally, parasite ranges and abundances are evolving, and various clinical management challenges in dogs and cats have emerged. Some of these are novel, such as hookworm multi-drug resistance, and others have been veterinary challenges for years, like Giardia's zoonotic potential. For these examples and others, there has been increased awareness of the need for appropriate veterinary anthelmintic use and stewardship. This review provides an update on selected gastrointestinal parasites of One Health importance, highlights gastrointestinal parasite global management and prevention recommendations, and summarises recent research, along with potential risks associated with pet importation and travel.

Parasites have long been a part of day-to-day routine veterinary care worldwide. As new veterinary management challenges have emerged in north America, such as hookworm multi-anthelmintic drug resistance, there have been other recently described changes in parasite frequencies, distributions and emergence (locally, regionally and worldwide). Detection of gastrointestinal parasite resistance and potential zoonotic concerns through recently introduced faecal testing methods (for example, molecular diagnostics), have highlighted the need for anthelmintic stewardship. Further, global veterinary guidelines for gastrointestinal parasite management, alongside recognition of the infectious disease impacts of pet importation and travel, have raised awareness of the clinical implications of canine parasites (current, emerging and evolving), One Health and subsequent need for veterinary attention to gastrointestinal parasite management and pet-owner communication. Clinical examples of gastrointestinal parasites of One Health importance will be used to spotlight these concerns and raise awareness of resources for veterinary management.

This case concerns a young female entire Border Collie who initially presented for reduced appetite and weight loss, and shortly thereafter developed bloody diarrhoea. Clinical history revealed that she was not currently on endoparasite prevention, lived on a sheep farm and was intermittently fed a raw meat-based diet, including the occasional sheep carcass. Physical examination was reported as a thin dog, with no other significant clinical findings aside from diarrhoea. The veterinarian treated her with metronidazole and milbemycin oxime/praziquantel and submitted a faecal sample as part of an infectious disease work-up. The dog improved rapidly (within 48 hours) and a faecal quantitative polymerase chain reaction test detected Echinococcus multilocularis. This polymerase chain reaction panel test detects 20 common gastrointestinal parasites, along with markers for hookworm benzimidazole treatment resistance and Giardia assemblages with zoonotic potential.

Register now to continue reading

Thank you for visiting The Veterinary Nurse and reading some of our peer-reviewed content for veterinary professionals. To continue reading this article, please register today.