Despite our understanding about the transmission and control of infections, they continue to present us with new challenges. Previously unknown infections appear. Known infections, such as Ebola, re-emerge.
The frequent occurrence of new outbreaks has prompted some to suggest we have entered a new era of infectious diseases. This impression has been encouraged by increasing reference to "emerging infectious diseases", a term coined in the 1990s and used since as a focus for research funding and policy making. Efforts to promote this as a distinct field have resulted in whole research programmes, conferences and journals.
However, this pattern of emergence and re-emergence is what infections have always done. It is nothing new.
Recent changes in human behaviour have influenced the emergence of particular infections. Increased urbanisation, crowded living conditions, the ease and speed of global migration, over-use of antibiotics, changes in animal husbandry and (potentially) climate change have created environments that favour transmission of infections.
The Ebola outbreak in West Africa was unprecedented in terms of the number of people affected. It appears to have come about more through environmental factors, rather than through new properties of the virus itself.
It is humans and how they have interacted with other animals and the environment that have changed.
Such recognition that the health of humans, animals and the viability of ecosystems are inextricably linked is the basis of a concept known as One Health. The One Health paradigm provides a conceptual framework for infectious diseases that acknowledges the complex interplay between human health, animal health and the environment, and with the factors that influence transmission of infections within their ecosystems.
The importance of this holistic approach is underscored by the fact that 60 per cent of known human infectious diseases have their source in domestic or wild animals, as do 75 per cent of emerging human infectious diseases and 80 per cent of the infectious micro-organisms that are potential agents of bioterrorism.
The One Health concept can be traced as far back as ancient Greecebut the term One Health is relatively new.
Veterinary researchers have grasped the concept more readily than those focused on human health, but the situation is changing. The One Health Initiative is now supported by many of the world's key human public health organisations.
Critical to the One Health concept is making it work in a way that acknowledges all components of the triad: humans, other animals and the environment.
Equal weighting should be given to each component of the triad, with particular acknowledgment of the importance of ecosystem changes and the holistic approach that is integral to the concept.
There has been surprisingly little recent collaboration between New Zealand's veterinary and medical schools. This is changing with the creation of One Health Aotearoa, a research collaboration led by Massey University and the University of Otago.
One Health Aotearoa is focused on infectious diseases and brings together medical and veterinary researchers, many of whom are internationally renowned for their work.
The intention is to strengthen New Zealand's capability in infectious disease research and training, facilitate and enhance interactions between infectious diseases disciplines, and provide a platform from which to rapidly respond to infectious diseases threats to New Zealand.
This type of research alliance is particularly pertinent to New Zealand given the agriculturally-based economy, the importance of zoonoses and the need for efficient use of resources.
One Health Aotearoa is still in its infancy. Judging by the overwhelming success of the first symposium run by the alliance last year, there is considerable enthusiasm for a more holistic approach to tacking infectious diseases among New Zealand scientists.
- Professor David Murdoch is Head of Pathology at the University of Otago
- Views expressed here are the writer's opinion and not the newspaper's. Email: editor@hbtoday.co.nz