This study applies a structured analytical framework to assess control strategies for high pathogenicity avian influenza (HPAI) in the turkey industry of the United States of America. A partial equilibrium model was developed to simulate market responses to disease control interventions. Economic outcomes of vaccination were quantified by comparing results from a simulated HPAI outbreak under two scenarios: non-vaccination and vaccination strategies. Based on the epidemiological outputs generated by the simulations of the United States Department of Agriculture’s Center for Epidemiology and Animal Health, the vaccination scenario generated economic outcomes that suggest potential benefits for both producers and consumers. As international trade restrictions increase, producer losses increase due to lost revenue and reduced supplies, while consumer gains grow due to diverted trade, which drives domestic price mitigation. This study not only develops a framework to assess HPAI control strategies but also provides an analysis to inform industry stakeholders and policy-makers in evaluating effective approaches for managing HPAI in the turkey sector of the United States of America.
Antimicrobial resistance (AMR) in bacteria originating from food-producing animals constitutes a significant challenge for food safety, public health, animal production and international trade. The acquisition of AMR genes by bacterial populations in both animals and humans obscures the inference of gene transfer directionality and complicates the assessment of selective pressures imposed by antimicrobial use. Zoonotic food-borne pathogens, such as Salmonella species, are key agents in transmitting AMR directly to humans via food. These pathogens frequently exhibit multidrug resistance, and their prevalence in food indicates a substantial public health risk. The application of antimicrobials in livestock production for therapeutic, prophylactic and growth promotion purposes is a recognised contributor to the emergence of resistance, although regulatory interventions have reduced these practices. Commensal and animal-specific pathogenic bacteria contribute to the indirect transfer of AMR genes, potentially affecting both animal and human health. Animal-derived food is a major reservoir for AMR pathogens; further research on contamination of plant-based food with AMR bacteria is crucial to assess its impact. Risk analysis of AMR is hindered by insufficient data, especially on AMR’s effects on animal health and production. Certain bacterial infections in animals have become more difficult to treat; however, untreatable infections are not yet widespread. The lack of international trade regulations regarding AMR bacteria in food complicates future policy creation and implementation. Enhanced surveillance, comprehensive risk analysis and international collaboration are therefore essential to mitigate the risks associated with AMR in food. Addressing these challenges is critical to safeguard food safety and animal health and maintain the integrity of global trade.
This issue of WOAH’s Scientific and Technical Review offers a timely collection of articles that are global in their reach and forward-looking in their ambition, embracing advances in the science and a more efficient One Health framing for antimicrobial resistance (AMR) governance, and responding to increased expectations for coordinated action across sectors. The articles address everything from stewardship in aquaculture to AMR governance frameworks, integrated surveillance, the economics of antimicrobial use, the role of diagnostics in vaccination and other preventative means in reducing antibiotic dependence. The content will appeal to researchers, policymakers, animal health professionals, and anyone who wants to understand where the science currently stands, and where it needs to go.
Antimicrobial resistance (AMR) poses a fundamental threat to global health security. The overuse and misuse use of antimicrobials for livestock production systems has been highlighted as playing an important role in the emergence and spread of AMR, prompting world leaders to agree on making efforts to reduce antimicrobial use by 2030. By analysing current economic realities and successful transition pathways, this article examines the economic dimensions of achieving ‘AMR neutrality’ in livestock, a state in which sustainable production is maintained with minimal antimicrobial use, balanced by preventive health measures and robust governance. AMR neutrality is ambitious but achievable, and economics can provide useful tools for charting the path forward.
Post-weaning diarrhoea (PWD) is a major driver of antimicrobial use (AMU) in European pig production. The European Union’s 2020–2025 multi-actor project Alternatives to Veterinary Antimicrobials, known as AVANT, evaluated various strategies to prevent PWD, including faecal filtrate transplantation (FFT), bacteriophage cocktails, immunostimulants, feed additives and fibre-based nutritional interventions. Field trials demonstrated that FFT and dietary inclusion of 5% alfalfa can reduce AMU at farm level by 21% and 6%, respectively. However, extrapolated to EU scale, these strategies would lower total livestock AMU by just 1.9% (FFT) and 0.5% (alfalfa) by 2035, far below the EU target of 50% reduction by 2030. The project’s findings indicate that no single alternative can substantially reduce AMU for PWD. As PWD is closely linked to nutritional and social stressors around weaning in current pig farming practices, eliminating reliance on metaphylactic (group) treatment requires optimised feeding and management strategies that minimise weaning-related stress, support early gut microbiome development and feed intake, and enhance disease prevention. If optimal health cannot be ensured, eliminating metaphylaxis is unrealistic, as treatment remains necessary for animal welfare. ‘Raised Without Antibiotics’ systems show that metaphylactic AMU can be replaced by individual treatment, while concomitantly enhancing animal health and welfare. However, these systems require substantial investment in infrastructure, training and coordination of the pig production chain. Widespread adoption of production systems that minimise AMU to the lowest possible levels requires policies that encourage infrastructure investments as well as regulatory frameworks that engage consumers with standards allowing informed choices and fair market competition. This requires significant political will.
The aim of the European Union Innovation Action ‘Alternatives to Veterinary Antimicrobials’, known as AVANT, was to develop new, targeted, non-antibiotic alternatives for the control of post-weaning diarrhoea in pigs. The project focused on four types of alternatives: gut microbiota modulators to maintain a healthy microbiome, therapies targeting the pathogen (enterotoxic Escherichia coli), immunostimulants and feeding strategies (dietary formulations). Up to now, limited regulatory guidance and support for the development and authorisation of alternatives to antimicrobials have been established. The lack of guidance leads to uncertainties in how to progress towards a marketing authorisation in the European Union, either as a veterinary medicinal product or as a feed additive. This article reviews the regulatory framework for seven specific, mostly orally administered alternatives to antibiotics: synbiotics (combinations of probiotics and prebiotics), faecal microbiota transplantation (FMT)/faecal filtrate transplantation (FFT), bacteriophages, polymers, immunostimulants (oral and injectable) and feeding strategies. The potential legal classification of these interventions is evaluated, together with the data requirements for authorisation in the European Union. A particular focus is placed on FMT/FFT, which have shown promising results in reducing diarrhoea prevalence. Several hurdles need to be addressed to facilitate applications for marketing authorisations/registrations, as applicable. The development of innovative, non-antibiotic interventions in livestock production is a societal priority that requires legislative support. The article concludes with a set of pragmatic strategies to facilitate the registration and use of such interventions.
Antimicrobial resistance (AMR) is a critical global threat to human, animal and environmental health and has received increasing attention from stakeholders worldwide. The overuse and misuse of antimicrobials in both human and veterinary medicine have significantly accelerated the emergence and spread of antimicrobial-resistant microorganisms. On the veterinary side, significant efforts have been undertaken in livestock to reduce antimicrobial use (AMU) and minimise the spread of AMR. The aim of this review was to provide an overview of current trends in AMU and AMR in food-producing animals, to identify the main constraints and mitigation strategies related to AMR, and to highlight future directions and key research gaps. A global reduction in the total quantity of antimicrobials intended for use in animals has been reported, with prospects for a continued downward trend. A positive correlation between the use of certain classes of antimicrobials and bacterial resistance in specific pathogens of importance to both animal and human health has been observed. Integrated surveillance programmes for AMU and AMR have played a crucial role in generating these AMR data and in guiding the formulation of recommendations. For this article, the Hazard Analysis and Critical Control Point framework was used as an approach to structure and customise some examples of on-farm intervention strategies aimed at both reducing AMU and minimising AMR. The article outlines future challenges in mitigating AMR in animal production that must be addressed to preserve the efficacy and longevity of existing antimicrobials, while supporting sustainable animal production practices.
In today’s world, what does antimicrobial stewardship (AMS) mean? Does it have the same meaning to people around the world and across One Health sectors? The objective of this article is to summarise the history and terminology of AMS, the ‘five Rs’ of AMS and key metrics and decision support tools, illustrate concepts through global case studies, identify barriers and facilitators, and propose a standardised definition of AMS in animal health. From the historical origins and uses of the word ‘stewardship’, the concepts of having responsibility, being accountable to someone or something, and the care of a valuable resource have been strong consistent themes. Across human and animal medicine, there are differences in the scope and content of what is considered prudent and responsible use, as well as AMS, and while these differences merit acknowledgement, they arise naturally from the different settings of medicine in these sectors. Fundamentally, the words capturing the concept of AMS are not as important as the intent and meaning they convey; the language should not be considered a barrier to action. When the scope of AMS incorporates aspects of the five Rs – responsibility, review, reduce, refine, and replace – it acknowledges that there are many aspects of AMS already in place in good animal rearing. Across the regions of the world, case studies have demonstrated highly successful and different approaches to stewardship initiatives and programmes in various economic settings. Challenges exist, but they do not prevent improvement and global expansion of AMS. Next steps to facilitate future AMS actions must address clarity and consistency in communication about AMS in animals, including a globally accepted definition. The goal of this article is to advance the concept of practical AMS by reducing the need for antimicrobial use, and, when antimicrobial use is necessary, by responsible and prudent use informed by AMS principles and programmes. Improving and optimising animal health is a key AMS tool.
Antimicrobial resistance (AMR) represents a growing global health concern with major implications for aquaculture, the farming of aquatic animals and algae, such as fish, crustaceans, molluscs and seaweeds. Misuse and overuse of antibiotics in aquaculture can drive the emergence of resistant bacteria, threatening aquatic animal health and posing risks to human health through the food chain. Aquaculture’s close connection to the aquatic environment makes it particularly vulnerable, as antibiotic residues and pollutants from aquaculture, agriculture and wastewater can enrich the resistome and promote the selection and spread of resistance genes in aquatic ecosystems. The aquatic environment acts as both a reservoir and a vector for AMR, enabling dissemination not only through food, but also via occupational and recreational water exposure and wildlife contact. Addressing AMR in aquaculture requires a One Health approach that acknowledges the interdependence of human, animal and environmental health. This article explores the historical emergence of AMR in aquaculture, focusing on the role of mobile genetic elements, such as plasmids, integrons and transposons, in horizontal gene transfer. It assesses trends in phenotypic resistance and presents a comprehensive overview of current surveillance and mitigation strategies aligned with One Health principles. International guidance from the World Health Organization, the Food and Agriculture Organization of the United Nations and the World Organisation for Animal Health is discussed, with emphasis on harmonised antimicrobial use surveillance and improved transparency. Advances in antimicrobial susceptibility testing and molecular diagnostics, including whole genome sequencing, are presented as tools to enhance AMR surveillance. Key recommendations include strengthened, system-appropriate biosecurity and on-farm management to prevent disease introduction and reduce antimicrobial reliance. While vaccination has delivered sustained reductions in antimicrobial use in intensive finfish systems in high-income settings, notably Atlantic salmon, it remains unavailable for many species and production systems in low- and middle-income countries. In crustacean aquaculture, where vaccination is not feasible, there is a need for greater emphasis on affordable, validated non-antibiotic disease control approaches, including immunostimulants, probiotics and phage-based interventions, integrated within broader biosecurity frameworks.
Antimicrobial resistance (AMR) is a complex and multifaceted One Health challenge. Its inherently interconnected and cross-sectoral nature complicates the evaluation and prioritisation of interventions, particularly when inter-sectoral One Health effects are relevant. Despite growing recognition of the need to assess AMR interventions from a One Health perspective, significant methodological gaps remain – particularly in quantifying the connections between the human, animal and environmental sectors and incorporating these interdependencies into the prioritisation of interventions. This article summarises a set of tools that have been developed and implemented to support more comprehensive assessments of AMR interventions by the Selecting Efficient Farm-level Antimicrobial Stewardship Interventions from a One Health perspective, or SEFASI, consortium. The tools are grouped into four categories based on the type of insight they provide: i) quantifying and characterising AMR burden, ii) understanding AMR dynamics, iii) understanding sector-specific intervention impacts and iv) evaluating cross-sectoral economic costs and effects. These tools utilise a range of methods including statistical, mathematical, static and dynamic modelling techniques. Although the use of tools presented is constrained by the availability of epidemiological and economic data, they represent an important step towards addressing the cross-sectoral complexity of AMR. This work introduces practical approaches and highlights how integrating methods with diverse objectives across contexts can enhance understanding and prioritisation of cross-sectoral strategies. It also underscores the value of conceptual and applied frameworks to guide data collection, strengthen capacity for evaluating One Health AMR interventions, and support evidence-based decision-making.
Antimicrobial resistance (AMR) presents a complex global health challenge requiring coordinated action across human, animal, plant and environmental sectors. Context-specific One Health governance is essential to unlocking the full potential of applying a One Health approach to effectively mitigate AMR. Drawing on empirical examples from countries implementing One Health governance, this article explores how One Health governance – defined as the structures, processes and mechanisms that enable intersectoral coordination, collaboration and decision-making across the human, animal, plant and environmental health sectors – can be used to overcome key barriers to implementing One Health approaches. The authors propose a set of normative principles, including transparency, sustainability, inclusivity and equity, to guide One Health governance, and identify six core dimensions – participation, leadership, decision-making, coordination, resourcing and accountability – that should be considered when designing governance models. The need for context-specific adaptation is emphasised, recognising that governance solutions must align with national political, institutional and socio-economic realities. While One Health governance offers considerable promise, the authors also reflect on enduring challenges, including entrenched sectoral silos, unequal power dynamics, and reliance on external funding. Sustained investment in interdisciplinary capacity strengthening, long-term resourcing strategies, and inclusive and transparent decision-making mechanisms are all needed to support resilient and effective governance in addressing AMR.
A One Health approach is widely recognised as key in addressing antimicrobial resistance (AMR) and is increasingly reflected in national action plans and global strategies. However, there is limited practical guidance on how to integrate a One Health perspective into the prioritisation and evaluation of AMR interventions to support decision-making. This article proposes a qualitative framework titled One Health Criteria to support decision-making on AMR interventions from a One Health perspective. It is based on assessment and characterisation of the setting where the intervention may be implemented, enabling early assessment of intervention impact according to outlined criteria (organised in themes and characteristics). It is a flexible, principle-based approach to guide AMR intervention planning and decision-making at all stages and levels, adaptable to diverse contexts. By enabling structured comparison of countries’ One Health profiles, the framework also promotes transferability and cross-learning for AMR intervention prioritisation. The authors identify three key themes that influence intervention success in a One Health perspective: i) ecosystem connectivity within and between sectors; ii) systemic societal factors, such as governance, policy and infrastructure; and iii) data availability to inform action. While this thematic approach supports early prioritisation, it is not a substitute for detailed analyses or economic evaluations where data permit. The authors aim to provide a practical tool for researchers and policy-makers to enhance the design and selection of AMR interventions within a One Health perspective. Future research should focus on refining the proposed themes and characteristics and developing robust methods to monitor and evaluate them.
The last comprehensive Scientific and Technical Review issue on antimicrobial resistance (AMR) in the animal health sector was published by the World Organisation for Animal Health (WOAH) in 2012 [1]. At that time, AMR was recognised as a growing concern, but its visibility in the political arena was limited, and its economic and environmental dimensions were less clearly articulated. Much has changed in the intervening 13 years. AMR is now widely acknowledged as one of the most pressing global health threats, sitting alongside climate change and pandemic preparedness in its scope and urgency. This Review issue arrives at a pivotal moment to take stock of progress, lessons learnt and the path forward. This Review issue is structured into five interconnected sections, designed to reflect the breadth of the challenge: – Section 1: Understanding AMR. Articles address the impacts of AMR across health, economic and environmental dimensions; cross-sectoral transmission dynamics; and implications for food safety, animal production and trade. – Section 2: Monitoring and surveillance. This section reviews current surveillance systems, integrated initiatives at national and regional levels, and innovations to strengthen monitoring of AMU and AMR. – Section 3: Interventions. This section focuses on prevention and stewardship, covering biosecurity, vaccination, diagnostics, alternatives to antibiotics, stewardship, and the socio-economic evaluation of interventions. – Section 4: Sector-specific challenges and advances. Articles examine AMR in livestock, aquaculture, companion animals and wildlife, recognising both sectoral specificities and cross-sectoral linkages. – Section 5: Cross-cutting themes. The final section explores governance, economics, stakeholder engagement and environmental dimensions, highlighting the broader systems context within which AMR evolves. Collectively, these sections are designed to provide a ‘state of the art’ synthesis, one that is evidence-informed, globally relevant and forward-looking.
Antimicrobial resistance (AMR) is a complex, cross-sectoral global health threat. AMR, along with other health risks, transcends traditional sector boundaries – it emerges and spreads across humans, animals, food systems and the environment – necessitating collaboration between human health, animal health and environmental disciplines. Therefore, a successful One Health response to AMR depends on the active engagement and collaboration of all key stakeholders, and on the alignment of actions for preserving the effectiveness of antimicrobials and thus addressing human health and animal welfare, securing food systems, safeguarding trade and economies, and strengthening resilience to future pandemics. In a multiple stakeholder landscape, international organisations and global initiatives are essential for coordinating cross-country and cross-sector actions, fostering cooperation, and facilitating data sharing through open access platforms. Currently, funding for One Health initiatives remains insufficient, despite growing recognition of their importance. This funding gap hampers the development and implementation of effective, integrated AMR strategies. Funding One Health is necessary because siloed investments are inefficient and silos increase the risk of duplicating efforts. Coordinated funding allows for integrated surveillance, stewardship and innovation across sectors, providing better solutions and long-term sustainability. The maturation of One Health programmes depends on having common goals, structured agendas, stakeholder alignment and measurable incentives, which drive meaningful and sustainable impact. Thus, cross-sector collaboration and stakeholder engagement should not be underestimated.
In recent years, the importance of working holistically on the global One Health and One Welfare agendas has become evident. The success of these policies in addressing shared challenges depends on a science-based global strategy for animal welfare that allows local efforts to resolve conflicts related to how human beings take advantage of natural resources, including domestic and wild animals. These policies need to be developed jointly by the World Organisation for Animal Health, the World Health Organization and the Food and Agriculture Organization of the United Nations and in line with the United Nations' Sustainable Development Goals. They should be based on scientific evidence, gathered from existing information and through transdisciplinary research, to quantify synergies and trade-offs between environmental, social, economic and animal welfare criteria. This approach will make it possible to articulate and implement local policies and solutions associating animal welfare with efficient and sustainable livestock production, biodiversity conservation and disease prevention, mitigation of greenhouse gas emissions and climate change, economic and rural development, biomedical research based on ethical principles, and responsible animal ownership.
In the past 100 years, thanks to the discovery and development of antimicrobial therapies, human and veterinary medicine have made a leap forward in treating infectious diseases. However, resistance mechanisms quickly appeared and spread in all sectors - human, animal and environmental - throughout the world, thus jeopardising the progress made. Awareness has been raised only gradually but is now prominent at the global level, due in large part to the action of international organisations such as the World Organisation for Animal Health (WOAH), the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO), and antimicrobials are considered a global public health good to be preserved. Under the leadership of WOAH in particular, the actions undertaken in research, surveillance, information, training, awareness and communication are moving in the right direction towards responsible and prudent use of antimicrobials. In the next 100 years, the fight against antimicrobial resistance will undeniably remain a crucial challenge for public health, veterinary public health and agriculture. Concerted efforts and scientific innovations, such as in functional genomics and artificial intelligence, could offer solutions to mitigate the impact of this growing threat. A multidisciplinary and comprehensive One Health approach is necessary to successfully address antimicrobial resistance. International collaboration remains crucial, and international organisations such as WOAH, WHO, FAO and the United Nations Environment Programme must continue their essential role in coordinating these efforts.
John Brooksby was an outstanding Scottish veterinary virologist who worked at the Pirbright Institute (Pirbright) for 40 years, including 16 as the institute's director. He devised quantitative methods for measuring neutralising antibodies and perfected a complement fixation test for the diagnosis, typing and strain differentiation of foot and mouth disease (FMD), especially when combined with neutralisation. He identified four of the seven types of FMD virus (FMDV) and many subtypes. Consequently, the institute was designated the World Reference Laboratory for FMD. As director, Brooksby also oversaw advances in the pathogenesis, epidemiology and aerobiology of FMD and other diseases. His advice on the prevention and control of FMD was widely sought by international organisations and individual countries. Fred Brown was an eminent English biochemist and molecular virologist. He joined the Biochemistry Department at Pirbright in 1955, became head of the department in 1964, and in 1980 became deputy director of the institute. Advances under his leadership included the use of aziridines as inactivating agents for vaccine production, purification of FMDV suitable for biochemical analyses, demonstration of the infectivity of isolated RNA, analysis of the genomic and antigenic structure of FMDV, solving of the atomic structure of FMDV and demonstration of the potential for synthetic peptide vaccines to protect animals against virus challenge.
Antimicrobial resistance (AMR) has been described as a silent pandemic - one that is ever-present, ubiquitous and growing but often insidious and overlooked. A true One Health issue, AMR affects people, animals, plants, crops and the environment in complex and interconnected but poorly understood ways, and the impact will continue to increase. In animals, AMR affects animal health, welfare and production and is also considered a food safety, food security and substantial economic issue. This article describes recent advances in addressing AMR in bacteria from animals, focusing on surveillance, applied stewardship, new drug development and alternatives to antimicrobials, strengthening animal health systems, changes in global awareness, and obstacles to effective surveillance and stewardship.
H5Nx A/Goose/Guangdong/1/96 Eurasian lineage high pathogenicity avian influenza (HPAI) viruses have been the main HPAI strains detected globally since 2005. These have spread around the world, causing a panzootic that has spanned six continents, with continual threat to not only wild and captive birds and poultry, but also wild, captive and domestic mammals and humans. The viruses' ecology and epidemiology - especially the 2.3.4.4b clade - have changed, with over 489 species of birds infected and spreading the virus over migratory routes. This results in the death of many birds, including endangered species, and serves as a source of transmission to poultry and mammals. Improved surveillance and sharing of HPAI virus sequences, metadata and viruses across the veterinary, public health, wildlife and environment sectors are needed to elucidate the population dynamics of the infections, which is crucial to addressing this complex One Health issue. The development of appropriate mitigation strategies or changes in husbandry, production and selling practices can reduce the risk of viruses being introduced into farms, as well as their amplification and viral evolution, and any spill-back to wild birds. Approaches to prevention and control of HPAI in countries where these 2.3.4.4b viruses remain entrenched in poultry, or places at risk of virus introduction via wild bird populations, involve measures to reduce the effects of the disease in poultry (including enhanced farm bio-security, vaccination, zoning and compartmentalisation). Their uptake reflects the difficulties encountered in relying solely on biosecurity for disease prevention and on stamping out alone for virus control and elimination. The World Organisation for Animal Health's Terrestrial Animal Health Code allows use of vaccination of poultry under specific conditions and without negatively impacting HPAI-free status if appropriate surveillance is conducted, thus supporting safe trade in poultry and poultry products. Nevertheless, concerns regarding loss of valuable export markets still interfere with greater utilisation of vaccination.
