December 2014
I was invited to give a talk for an event on ‘Ebola: Perspectives on the Epidemic ̴ Where to Begin’ taking place on 20th November 2014.[1] The immediate ethical concerns of the outbreak were raised: the dire conditions of the people the disease is affecting, and the consequent response from the international community. However, an additional point to reflect upon was that Ebola, just one of many zoonotic diseases, raises questions that can be rendered with the broadest brush – the makros kósmos – the idea of a global health response.
Zoonotic viruses, diseases that transmit between humans and non-human animals, are intimately linked to ecological niches; each virus can be stirred from its environment through different connections, and each has a different potential for illness, endemic and pandemic. Questions like ‘Why now?’ and ‘What next?’ are significant, then, not only in the local devastation that these diseases cause, but also in respect to their effect on the global community. For Ebola, at this point we are dealing in the unknowns and knowns of the ‘ecology of the virus’. This is because until now it has been found only in remote areas of Africa (but nevertheless decimating those communities it comes into contact with), and little was known about its potential for, and behaviour during an epidemic. We know little about the natural history of the virus – we still don’t know the reservoirs,[2] or why so rarely it emerges in human populations. However, I suspect that many – those studying the nature of the virus in its natural environment – thought that not only an outbreak of this magnitude was possible, but also likely; and filling these gaps will affect our ability to formulate clinical and ethical responses.
The emergence of zoonotic diseases is becoming ever more common; and they are cropping up in far more diverse places and often not always those that are remote, wilderness fringed communities (recently: bird flu in Canada, Germany, Netherlands and the UK; this year in South Korea, Japan and Malaysia). New kinds of zoonotic virus, such as Marburg, Hanta, Hendra, Nipah, and MERS viruses, are threatening humanity, our closest relatives (the great apes), and other animals at unprecedented levels;[3] and their effects on the wider ecologies (including how we respond to them) is devastating.
We therefore need to appreciate how and why the environment only spits them out when challenged or stressed; why the viruses spill over and emerge in human populations only sometimes; and thereby understand how we might better avoid them altogether?[4]
In this respect, an emerging area of study, called One Health, is demonstrating that not only will a healthy ecology be less likely to send these viruses our way, but it can also protect us by buffering and ‘soaking up’ zoonoses.[5] So, we need to look to other solutions of prevention, not just the ‘pandemic plans’ that tend to decimate local animal populations (culling of domestic animals and local wildlife), threaten ecological diversity and socio-economic sustainability (the impacts on agricultural and cultural ecological co-dependence), and then tend only to be useful after the event and once human-to-human transmission is sustained.
Overall, we ought to be looking to better ways to minimise the emergence of these diseases through an ecological perspective; understanding not only the human effects and solutions that presences (vaccines, public health measures), but also the reservoirs, connections and drivers of disease emergence. It is clear that land use (mining, oil refining), deforestation, and urbanisation are having an unprecedented effect on these ecological niches; so, we need to start accounting for local needs – including land management, like farming and husbandry; economic and political priorities in these countries that are most at risk; and the global interactions that are conditional on disease emergence.
These debates need to start off on better footing, by engaging with a much broader expert base and expanding traditional and often too narrow public health concerns.[6] This dialog must include veterinarians, biologists, ecologists and anthropologists; and as diverse as economists and historians. The risks are known, if not well understood, and we need to develop ideas about how human beings can better and more effectively live within the ecology that potentially harbours these diseases.
[1] My thanks to the organiser of the event, Suzanne Clarke, a MED2 Student from the Faculty of Medicine, Dalhousie University. Suzanne also assisted with the drafting of this blog. The event was presented by Dal Med Global Health Initiative, Dalhousie University Global Health Office, Capital Health, Dalhousie Medical Students Society, Health Association of African Canadians & The Tropical Medicine Student Interest Group, and broadcast in multiple locations across The Maritimes, Canada. The opinions expressed here are my own.
[2] Probably bats; but we still don’t know how it gets into them, how it resides there, or how it then emerges in susceptible populations like human beings and other primates; Plowright, R. et al. 2015. Ecological Dynamics of Emerging Bat Virus Spillover. Proceedings of the Royal Society B 282: 20142124; Pignott, D. et al. 2014. Mapping the Zoonotic Niches of Ebola Virus Disease in Africa. eLife 3: e04395.
[3] See: Genton, C. et al. 2014. How Ebola Impacts Social Dynamics in Gorillas: A multistate Modeling Approach. Journal of Animal Ecology doi: 10.1111/1365-2656.12268; Walsh, P. et al. 2007. Natural History Miscellany: Potential for Ebola Transmission between Gorilla and Chimpanzee Social Groups. The American Naturalist 169: 684-689.
[4] Capps, B., Bailey, M., Bickford, D., Coker, R., Lederman, Z., Lover, A., Lysaght, T., and Tambyah, P. (In press; 2014). Introducing One Health to the Ethical Debate about Zoonotic Diseases in South East Asia. Bioethics.
[5] See: N. Harris & R. Dunn. Species Loss on Spatial Patterns and Composition of Zoonotic Parasites. Proc R Soc B 2013; 280: 20131847; F. Keesing, et al. Impacts of Biodiversity on the Emergence and Transmission of Infectious Diseases. Nature 2010; 468: 647–652.
[6] Capps, B. and Lederman, Z. 2014. One Health and Paradigms of Public Biobanking. Journal of Medical Ethics.Online first doi:10.1136/medethics-2013-101828.
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