The episodic resurgence of highly pathogenic avian influenza H5 virus

Highly pathogenic avian influenza (HPAI) H5N1 activity has intensified globally since 2021, increasingly causing mass mortality in wild birds and poultry and incidental infections in mammals1-3. However, the ecological and virological properties that underscore future mitigation strategies still remain unclear. Using epidemiological, spatial and genomic approaches, we demonstrate changes in the origins of resurgent HPAI H5 and reveal significant shifts in virus ecology and evolution. Outbreak data show key resurgent events in 2016-2017 and 2020-2021, contributing to the emergence and panzootic spread of H5N1 in 2021-2022. Genomic analysis reveals that the 2016-2017 epizootics originated in Asia, where HPAI H5 reservoirs are endemic. In 2020-2021, 2.3.4.4b H5N8 viruses emerged in African poultry, featuring mutations altering HA structure and receptor binding. In 2021-2022, a new H5N1 virus evolved through reassortment in wild birds in Europe, undergoing further reassortment with low-pathogenic avian influenza in wild and domestic birds during global dissemination. These results highlight a shift in the HPAI H5 epicentre beyond Asia and indicate that increasing persistence of HPAI H5 in wild birds is facilitating geographic and host range expansion, accelerating dispersion velocity and increasing reassortment potential. As earlier outbreaks of H5N1 and H5N8 were caused by more stable genomic constellations, these recent changes reflect adaptation across the domestic-bird-wild-bird interface. Elimination strategies in domestic birds therefore remain a high priority to limit future epizootics.

Supporting One Health for Pandemic Prevention: The Need for Ethical Innovation

Bioethics is a field in which innovation is required to help prevent and respond to zoonotic diseases with the potential to cause epidemics and pandemics. Some of the developments necessary to fight pandemics, such as COVID-19 vaccines, require public debate on the benefits and risks of individual choice versus responsibility to society. While these debates are necessary, a more fundamental ethical innovation to rebalance human, animal, and environmental interests is also needed. One Health (OH) can be characterized as a strategy that recognizes and promotes the synergy between human, animal, and environmental health. Yet, despite the recognition that these entities are interdependent, there is a pronounced inequality in the power relations between human, non-human animal, and the environmental interests which threatens the well-being of all. Until OH can ensure the moral status of animals and the environment and thereby the equal consideration of these interests, it will struggle to protect non-human interests and, as a result, human health. To create a sustainable health system requires a renewed concept of justice that is ecocentric in nature and an application of OH that is flexible and responsive to different ethical interests (e.g., person-centred care and physician responsibilities). Ultimately, to save themselves, humans must now think beyond themselves. Bioethics must assume a key role in supporting the developments required to create and maintain relationships able to sustain environmental and human health.

Phylodynamic analysis of the highly pathogenic avian influenza H5N8 epidemic in France, 2016-2017

In 2016-2017, France experienced a devastating epidemic of highly pathogenic avian influenza (HPAI) H5N8, with more than 400 outbreaks reported in poultry farms. We analyzed the spatiotemporal dynamics of the epidemic using a structured-coalescent-based phylodynamic approach that combined viral genomic data (n = 196; one viral genome per farm) and epidemiological data. In the process, we estimated viral migration rates between départements (French administrative regions) and the temporal dynamics of the effective viral population size (Ne) in each département. Viral migration rates quantify viral spread between départements and Ne is a population genetic measure of the epidemic size and, in turn, is indicative of the within-département transmission intensity. We extended the phylodynamic analysis with a generalized linear model to assess the impact of multiple factors-including large-scale preventive culling and live-duck movement bans-on viral migration rates and Ne. We showed that the large-scale culling of ducks that was initiated on 4 January 2017 significantly reduced the viral spread between départements. No relationship was found between the viral spread and duck movements between départements. The within-département transmission intensity was found to be weakly associated with the intensity of duck movements within départements. Together, these results indicated that the virus spread in short distances, either between adjacent départements or within départements. Results also suggested that the restrictions on duck transport within départements might not have stopped the viral spread completely. Overall, we demonstrated the usefulness of phylodynamics in characterizing the dynamics of a HPAI epidemic and assessing control measures. This method can be adapted to investigate other epidemics of fast-evolving livestock pathogens.

The Precautionary Principle in Zoonotic Disease Control

The COVID-19 pandemic has shown that zoonotic diseases are a great threat for humanity. During the course of such a pandemic, public health authorities often apply the precautionary principle to justify disease control measures. However, evoking this principle is not without ethical implications. Especially within a One Health strategy, that requires us to balance public health benefits against the health interests of animals and the environment, unrestricted use of the precautionary principle can lead to moral dilemmas. In this article, we analyze the ethical dimensions of the use of the precautionary principle in zoonotic disease control and formulate criteria to protect animals and the environment against one-sided interpretations. Furthermore, we distinguish two possible conceptions of the precautionary principle. First, we notice that because of the unpredictable nature of zoonotic diseases, public health authorities in general focus on the idea of precaution as preparedness. This reactive response often leads to difficult trade-offs between human and animal health. We therefore argue that this policy should always be accompanied by a second policy, that we refer to as precaution as prevention. Although zoonotic diseases are part of our natural world, we have to acknowledge that their origin and global impact are often a consequence of our disturbed relation with animals and the environment.

Stamping Out Animal Culling: From Anthropocentrism to One Health Ethics

Culling is used in traditional public health policies to control animal populations. These policies aim primarily to protect human interests but often fail to provide scientific evidence of effectiveness. In this article, we defend the need to move from a strictly anthropocentric approach to disease control towards a One Health ethics, using culling practices as an example. We focus on the recent badger culls in the UK, claiming that, based on data provided by the English Government, these culls may be unjustified, all thing considered. We highlight the relevance of ethical reasoning rooted in One Health for this discussion, and make several suggestions including a moratorium on culling until data are provided to support the effectiveness of culling; to conduct a randomized trial to compare proactive culling with alternative methods; to apply deliberative democratic methods to assess public opinion towards the culls, and to find in Brexit an opportunity for aiming for more effective control measures.

One health ethics: a response to pragmatism

Johnson and Degeling have recently enquired whether one health (OH) requires a comprehensive normative framework, concluding that such a framework, while not necessary, may be helpful. In this commentary, we provide a context for this debate, and describe how pragmatism has been predominant in the OH literature. We nevertheless argue that articulating a comprehensive normative theory to ground OH practice might clear existing vagueness and provide stronger guidance in relevant health dilemmas. A comprehensive theory will also be needed eventually to ground notions such as universal good. We, thus, call for the systematic articulation of a comprehensive, metaethical theory, concomitantly with already ongoing normative work.

One Health: How Interdependence Enriches Veterinary Ethics Education

What does One Health imply for veterinary ethics education? In order to answer this question, we will first have to establish what One Health itself involves. The meaning and scope of One Health, however, cannot be established without reference to its values-whose health matters? Veterinary ethics education is well equipped to facilitate such an open-ended inquiry into multispecies health. One Health also widens the scope of veterinary ethics by making salient, among other fields, environmental ethics, global health justice, and non-Western approaches to ethics. Finally, One Health requires students to engage with interdependence. Discussing three levels of interdependence, we argue that veterinary ethics stands to benefit from a more contemplative pedagogy.

Interspecific visitation of cattle and badgers to fomites: A transmission risk for bovine tuberculosis?

In Great Britain and Ireland, badgers (Meles meles) are a wildlife reservoir of Mycobacterium bovis and implicated in bovine tuberculosis transmission to domestic cattle. The route of disease transmission is unknown with direct, so-called "nose-to-nose," contact between hosts being extremely rare. Camera traps were deployed for 64,464 hr on 34 farms to quantify cattle and badger visitation rates in space and time at six farm locations. Badger presence never coincided with cattle presence at the same time, with badger and cattle detection at the same location but at different times being negatively correlated. Badgers were never recorded within farmyards during the present study. Badgers utilized cattle water troughs in fields, but detections were infrequent (equivalent to one badger observed drinking every 87 days). Cattle presence at badger-associated locations, for example, setts and latrines, were three times more frequent than badger presence at cattle-associated locations, for example, water troughs. Preventing cattle access to badger setts and latrines and restricting badger access to cattle water troughs may potentially reduce interspecific bTB transmission through reduced indirect contact.

The good, the bad and the ugly: framing debates on nature in a One Health community

Originating in medical and veterinary spheres, the One Health concept stands as an open call for collaboration also between these disciplines or professions and those of environmental and social science. However, the communities of practice in question show uneasy or under-developed collaborations, due to a variety of factors. We argue that an important factor is the way issues are raised and questions are formulated, i.e., their framing. Based on complementary perspectives on health and knowledge, this overview provides an inter- and trans-disciplinary analysis of the role of the framing of « nature » in One Health discourses as a barrier or a facilitator to collaboration, as revealed by the scientific literature. We find that the lack of reflection by scientists about the framing under which they operate appears as a major factor of misunderstanding between disciplines, and a barrier for inter- and trans-disciplinary solutions to improve management of health risks and benefits. Hence, to build such solutions, framing will have to be a conscious and repeated step in the process, acknowledging and explaining the diversity of viewpoints and values. The interdisciplinary dialogues inherent in this process promote translation between scientific domains, policy-makers and citizens, with a critical but pluralistic recourse to various framings of health risks and benefits associated with nature, and a deep awareness of their practical and ethical consequences.

One Health as a moral dilemma: Towards a socially responsible zoonotic disease control

During the last decade, the concept of One Health has become the international standard for zoonotic disease control. This call for transdisciplinary collaboration between professionals in human, animal and environmental health has produced several successes in zoonotic disease control, surveillance and research. Despite the lack of a clear definition, a shared agenda or institutional governance, One Health has proven to be a fruitful idea. Due to its ambiguity, the One Health concept functions as a boundary object: by leaving room for interpretation to fit different purposes, it facilitates cooperation. In many cases, this results in the promotion of health of humans, animals and the environment. However, there are also situations in which this mutual benefit of a One Health approach is not that evident, for instance, when healthy animals are culled to protect public health. Although such a strategy could well be part of a One Health approach, it is hard to understand how this contributes to the health of concerning animals. Consequently, these practices often lead to public debate. This raises questions on how we should understand the One Health concept in zoonotic disease control. Is it really about equally improving the health of humans, animals and the environment and is this even possible? Or is it ultimately just public health that counts? In cases of conflict between different values, the lack of a universal definition of the One Health concept contributes to this complexity. Although boundary objects have many positive aspects, in the context of One Health and zoonotic disease control, this conception seems to conceal underlying normative differences. To address moral dilemmas related to a One Health approach in zoonotic disease control, it is important to reflect on moral status and the meaning of health for humans, animals and the environment.

Justice Is the Missing Link in One Health: Results of a Mixed Methods Study in an Urban City State

BACKGROUND

One Health (OH) is an interdisciplinary collaborative approach to human and animal health that aims to break down conventional research and policy 'silos'. OH has been used to develop strategies for zoonotic Emerging Infectious Diseases (EID). However, the ethical case for OH as an alternative to more traditional public health approaches is largely absent from the discourse. To study the ethics of OH, we examined perceptions of the human health and ecological priorities for the management of zoonotic EID in the Southeast Asia country of Singapore.

METHODS

We conducted a mixed methods study using a modified Delphi technique with a panel of 32 opinion leaders and 11 semi-structured interviews with a sub-set of those experts in Singapore. Panellists rated concepts of OH and priorities for zoonotic EID preparedness planning using a series of scenarios developed through the study. Interview data were examined qualitatively using thematic analysis.

FINDINGS

We found that panellists agreed that OH is a cross-disciplinary collaboration among the veterinary, medical, and ecological sciences, as well as relevant government agencies encompassing animal, human, and environmental health. Although human health was often framed as the most important priority in zoonotic EID planning, our qualitative analysis suggested that consideration of non-human animal health and welfare was also important for an effective and ethical response. The panellists also suggested that effective pandemic planning demands regional leadership and investment from wealthier countries to better enable international cooperation.

CONCLUSION

We argue that EID planning under an OH approach would benefit greatly from an ethical ecological framework that accounts for justice in human, animal, and environmental health.

Culling and the Common Good: Re-evaluating Harms and Benefits under the One Health Paradigm

One Health (OH) is a novel paradigm that recognizes that human and non-human animal health is interlinked through our shared environment. Increasingly prominent in public health responses to zoonoses, OH differs from traditional approaches to animal-borne infectious risks, because it also aims to promote the health of animals and ecological systems. Despite the widespread adoption of OH, culling remains a key component of institutional responses to the risks of zoonoses. Using the threats posed by highly pathogenic avian influenza viruses to human and animal health, economic activity and food security as a case exemplar, we explore whether culling and other standard control measures for animal-borne infectious disease might be justified as part of OH approaches. Our central premise is that OH requires us to reformulate 'health' as universal good that is best shared across species boundaries such that human health and well-being are contingent upon identifying and meeting the relevant sets of human and non-human interests and shared dependencies. Our purpose is to further nascent discussions about the ethical dimensions of OH and begin to describe the principles around which a public health agenda that truly seeks to co-promote human and non-human health could potentially begin to be implemented.