Updates on emerging and evolving gastrointestinal parasites in dogs and cats

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.