Over the three decades that I have worked in animal health, I have borne witness to the mounting effects of antimicrobial resistance (AMR) in animals. Just like in people, while bacterial infections in animals were once predictably treatable with routine antimicrobials, we now face resistant infections that make it harder to treat animals. Then we end up on a slippery slope of needing to use newer antimicrobials, helping to treat the infection but adding risks for development of even more resistance. Since antimicrobials used to treat animals are mainly the same or similar to those used in people, this cascade of resistance threatens both human and animal health.
As long as we raise animals for food, fiber, companionship, or conservation, we will have some need for antimicrobials. I believe we have an ethical obligation to treat disease in animals — and we have an equally important ethical obligation to do everything we can to reduce the human health impacts of antimicrobial overuse across species. To do that, we need clear guidance that veterinarians everywhere can turn to. Creating stewardship initiatives wherever animals exist — which is everywhere — is key to avoiding irreversible global-scale resistance.
Microbes don’t care who — or what — you are. These tiny organisms, many times smaller than a human cell, can travel through earth, water and air, between animals and plants and people, wreaking havoc. The development of antimicrobials revolutionized the treatment and prevention of infectious diseases in both humans and animals; indeed, antimicrobials have been a fundamental pillar of modern agriculture as well as modern medicine. But this foundation is crumbling — and use of antibiotics in animals, both livestock and pets, is a major contributor.
Population growth, increased mixing of humans and animals, climate change, and myriad other stressors have widened the scope of the spread of pathogens. Antimicrobials are a mainstay of treatment of infectious diseases but use of these miracle drugs exacerbates antimicrobial resistance — the phenomenon wherein viruses, bacteria and other microorganisms evolve so that they can evade the substances used to disable them. As AMR proliferates, it becomes more challenging to halt the spread of disease. If we ignore this issue, the consequences will be dire.
A systematic analysis published in the Lancet estimated that AMR was directly responsible for 1.3 million deaths and contributed to nearly 5 million more globally in 2019 alone. The World Health Organization found that human bloodstream infections caused by resistant E. coli and Salmonella increased by at least 15% between 2017 and 2020. To tackle this growing problem, it’s vital we address the use of antibiotics in both humans and animals.
As the world’s population expands and as economies develop, the demand for animal-based foods will continue to grow. Increases in livestock production need to happen without worsening the problem of AMR. Similarly, owning a dog, cat, or other companion animal, which is growing in popularity worldwide, makes it all the more important to manage infections in these non-human members of the family. And as long as we raise and keep animals, we have an ethical duty to treat them if they get sick.
But we also need to ensure that if we do use antibiotics, we are using them properly and only when needed. Antibiotic use in animals is not just an issue for veterinary medicine: Drug-resistant infections know no borders, and many pathogens can spread effectively between humans and animals. Antibiotic use in animals can ultimately lead to resistant infections in other species, and while the majority of antimicrobial resistance in humans presumably relates to antimicrobial use in humans, if even a small fraction of the millions of human lives and billions of dollars in health care costs can be reduced through improving antimicrobial use in animals, we have to act. As part of this, international guidance on antibiotic use in animals is sorely needed.
Antimicrobials are currently used unnecessarily to treat animals for a lot of the same reasons why it happens in human medicine: risk aversion, habit, inadequate awareness of alternative solutions, limited access to diagnostic testing, and a desire to “do something.” Because it can be difficult to change ingrained behavior, providing simple and practical guidance on antibiotic use to improve patient outcomes, particularly in low-resource settings, is crucial.
In 2022, the World Health Organization published “The Who AWaRe (Access, Watch, Reserve) antibiotic book,” a resource to guide human health professionals in selecting the best antibiotics for their patients, as well as the appropriate dosage, route of administration, and duration of treatment. In order to disseminate these guidelines, the WHO partnered with Firstline, a Canadian health technology platform, to ensure that crucial information for dealing with AMR could be easily shared around the world. Since its launch, the platform has helped practitioners in human health care settings ranging from small community hospitals to large tertiary care hospitals. These health care facilities have seen a significant increase in prescribing appropriateness, reduced antimicrobial consumption and reduced occurrence of opportunistic infections. Moreover, this platform has helped alleviate the workload of doctors and pharmacists.
My colleagues and I have launched a venture to provide open access companion animal treatment guidelines, but that’s just a start. We need more open-access versions for other animal sectors and countries. But the international community needs to get involved. We need broader efforts to address antimicrobial use in all species, sectors, and countries, and need a standardized, evidence-based approach. Ideally, we need VetAWaRe, an animal version of AWaRe that categorizes drugs and provides guidance on diagnosis, treatment, and control for point of care decisions. That can help ensure all antimicrobial use in animals happens under the guidance of a veterinary professional, and that all veterinary professionals have free access to antimicrobial guidelines.
This week, the U.N. General Assembly will meet to address the global threat of AMR. I will be attending and will be calling on support from veterinarian experts, political leaders, and the Quadripartite to establish mechanisms similar to that which exist for human health. We need to build on the success of AWaRe and, in the spirit of a coordinated, inter-sector, “One Health” response, develop VetAWaRe, a practical resource and categorization system that would complement and expand the WHO AWaRe guidance, using a similar framework that could be repeated for different animal species.
Broad access to information can speed up the implementation of safe practices everywhere, whether those practices affect intensively raised livestock in high-income countries, small stakeholders in sub-Saharan Africa, or the pet that sleeps on your bed every night.
Scott Weese , D.V.M., is a professor at the University of Guelph. He is a member of numerous national and international committees dealing with infectious diseases and antimicrobial resistance, including the Quadripartite (WHO, WOAH, FAO, UNEP) Global Leaders Group on AMR.
