November 2024 sees the annual Antibiotic Amnesty campaign, coordinated by RUMA-CAE (Responsible Use of Medicines Alliance – Companion Animals and Equine), which reminds us of the need for responsible stewardship of antibiotics. This initiative encourages veterinary practices and pet owners to return unused or out-of-date antibiotics, aiming to reduce unnecessary stockpiles and prevent indiscriminate use. The amnesty also serves as a timely prompt for us all to reflect on the rational use of antibiotics in companion animal care.
While antibiotics are invaluable in both human and veterinary medicine, their overuse has led to the rise of antimicrobial resistance, a threat that transcends species boundaries. In veterinary practice, the importance of rational antibiotic use cannot be overstated. As practitioners, we need to follow stringent guidelines, ensuring that antibiotics are prescribed only when necessary and always based on evidence, such as culture and sensitivity testing where possible. The global focus on One Health highlights how antibiotic misuse in animals can contribute to antimicrobial resistance in humans, underscoring our professional duty to make informed, judicious decisions.
Alongside antibiotics, antiparasitic treatments have come under scrutiny for potential overuse in companion animals. Regular parasite treatment may be important for preventing zoonotic diseases like toxocariasis, but a balance must be struck between safeguarding public health and preventing overuse of antiparasitic drugs. Increasing concerns about potential resistance to parasiticides, and about the environmental effects of the potent chemicals we use, mean that we should turn our attention to this class of drugs (British Veterinary Association, 2021).
There are many questions to be answered. What harm is caused to adult dogs and cats by roundworm infection? Apart from fipronil and imidacloprid, which research has found in 98% and 66% of freshwater samples, respectively (Perkins et al, 2021), what are the incidences and effects of the newer drugs that we use? How many actual cases of human toxocariasis are there annually in the UK? While estimates of cases can vary from 50 to 100 a year, very few showing notable signs of illness (Patterson, 2023), and the government's own survey of animal-related infections mentions very few cases annually. For example, no cases were reported in the first quarter of 2023, and one case was reported in the second quarter (UK Health Security Agency, 2024). Estimates for the annual spend on pet parasite treatments vary from £300 to £600 million (Daily Echo, 2018). Are we providing value for money? Research showing the presence of Toxacara ova in 86.6% of parks might suggest ineffective worming (Airs et al, 2023). Another way to look at it would be that despite that annual spend, the levels of ova are high, and does it matter, given the low number of human cases? We have made huge strides in improving antibiotic use. It is time to think about how we use parasiticides.