The One Health framework recognizes the interconnection of human health, animal health, and environmental health as a unified system. Emerging infectious diseases, antimicrobial resistance, food safety, and ecosystem services all reflect these interconnections. Animal welfare is increasingly recognized as an integral component of One Health, both because poor welfare conditions enable disease emergence and transmission, and because sentient animal suffering is intrinsically important within any framework that takes animal lives seriously.
One Health has gained major institutional traction through the Quadripartite — WHO, FAO, WOAH (OIE), and UNEP — which formally endorsed One Health as a unifying framework for addressing zoonotic disease risks, antimicrobial resistance, food safety, and ecosystem health. The 2022 One Health Joint Plan of Action established operational commitments across these areas. National One Health platforms now exist in most countries, though implementation depth varies considerably.
The historical separation of human medicine, veterinary medicine, and environmental science has been identified as a key barrier to effective response to interconnected health challenges. One Health addresses this by advocating for integrated surveillance, coordinated response, shared research infrastructure, and policy coherence across sectors. The COVID-19 pandemic, with its likely origin in human-animal interfaces, accelerated political support for One Health approaches.
The conditions that increase zoonotic disease risk frequently overlap with conditions that compromise animal welfare. Intensive confinement of large numbers of animals in close proximity creates conditions for pathogen amplification and mutation. Live animal markets, where multiple species come into close contact with humans and each other, represent high-risk interfaces. Wildlife trafficking moves animals — and their associated pathogens — across geographic barriers.
Research has established associations between certain intensive farming practices and pathogen emergence. High stocking densities, reduced genetic diversity in commercial breeds, and immunocompromise associated with welfare stress all potentially increase disease risk. While direct causal pathways from animal welfare to disease emergence are complex and contested, the co-occurrence of welfare problems and disease risk at the human-animal interface is well documented.
Improving animal welfare can reduce zoonotic disease risk through several mechanisms: reducing stress-related immunosuppression that makes animals more susceptible to infection; reducing crowding that enables pathogen transmission; reducing the conditions that favor viral mutation; and reducing reliance on prophylactic antibiotics that drive antimicrobial resistance. These co-benefits provide strong policy arguments for welfare improvements that go beyond animal welfare advocacy alone.
Antimicrobial resistance (AMR) is one of the most significant global health challenges, projected to cause millions of human deaths annually by 2050. Agriculture is a major driver of AMR through prophylactic and growth-promoting antibiotic use in livestock. The welfare connection is significant: antibiotics are used prophylactically partly because crowded, stressed animals are more susceptible to infection. Improving welfare conditions, particularly by reducing crowding and stress, can reduce the disease pressure that drives antibiotic use.
Several European countries have demonstrated that welfare improvements combined with reduced prophylactic antibiotic use are compatible with commercially viable livestock production. Denmark's reduction of antibiotic use in pig production, Netherlands' restrictions, and Sweden's long-standing low-use approach all demonstrate this compatibility. The welfare improvement-AMR reduction nexus provides compelling policy arguments for welfare reform that resonate beyond traditional animal welfare constituencies.
Healthy ecosystems support wildlife populations, and wildlife welfare is increasingly recognized as relevant to ecosystem function. Large animal populations provide trophic regulation, seed dispersal, and other ecosystem services. Compromising wildlife welfare through poaching, snaring, habitat destruction, and pollution affects both individual animals and ecosystem function.
Biodiversity loss, driven largely by habitat destruction and wildlife trade, reduces the functional diversity of ecosystems that support human and animal health. Maintaining wildlife populations and the ecosystems they inhabit is a welfare and health imperative. One Health approaches that integrate wildlife management, habitat protection, and disease surveillance address welfare and ecosystem dimensions simultaneously.
The "One Welfare" concept extends the One Health framework by explicitly incorporating animal welfare and human wellbeing alongside health. Recognizing that human welfare, animal welfare, and environmental integrity are interconnected — and that improving one often improves others — One Welfare provides a broader framing for integrated approaches. The One Welfare framework has been developed by researchers including Rebeca Garcia Pinillos and promoted through the One Welfare network.
Practical applications of One Welfare include: working animal welfare programs that improve both animal welfare and the economic welfare of dependent communities; mental health programs that recognize the role of animals in human wellbeing; food system transformation that addresses the welfare of farmed animals while improving nutritional outcomes for humans; and wildlife conservation programs that support both biodiversity and community livelihoods.
Integrating animal welfare into One Health policy frameworks requires moving beyond the traditional focus of One Health on infectious disease risk to encompass welfare as an intrinsic value. Progressive One Health advocates argue that a framework focused only on the instrumental value of animal health for human health is incomplete — that the suffering of sentient animals matters independently of disease risk.
Future directions include: developing integrated surveillance systems that include welfare indicators alongside health metrics; incorporating welfare standards into One Health national action plans; building interdisciplinary education that bridges veterinary, medical, environmental, and welfare sciences; and developing policy frameworks that recognize welfare co-benefits of disease prevention investments. The COVID-19 pandemic has created political momentum for One Health investment; channeling this momentum toward welfare-inclusive approaches is an important advocacy priority.