HIGH FLYERS THINK TANK

Emerging diseases – Ready and waiting?

The Shine Dome, Canberra, 19 October 2004

Summary report and outcomes

Global context of emergence

Disease-causing microbes have threatened human health and agricultural productivity for centuries and remain the major cause of death worldwide. This threat is ever-present today, and many believe it is on the increase. The implications of such threats were brought home only recently when several countries faced the new zoonotic (ie, transferred to humans from animals) disease of SARS (sudden acute respiratory syndrome) which rapidly spread to many countries, infecting and killing many people. In 2004 avian influenza (or bird ‘flu) caused mortalities in South-East Asia and gave Australian health professionals and poultry producers great concern. There is also an increasing trend of re-emergence of some ‘old' diseases previously considered contained, such as tuberculosis.

There are several factors that are contributing to the emergence of diseases (new and old):

Genetic mutation: Infectious agents are subject to genetic change and evolution that enable them to infect new hosts by altering their susceptibility to antimicrobial drugs and their responses to host immunity. Mutations may be precipitated by environmental factors such as pollution, resistance to pesticides or herbicides by pathogens and insect vectors, climate change impacts, and so on.

Geographic range: Modern transportation of people and produce, by air, ship or road, has enabled the wide-scale spread of infectious agents – sometimes quite rapidly around regions, countries and even globally. For example, it has recently been discovered that Cholera-producing bacteria are being transported to coastal regions around the world in ships' ballast water. Disease can also be spread by natural causes, for example the current spate of sugarcane smut in the Ord River region of northern WA is thought to have been introduced into Australia from Indonesia by tropical cyclones.

Human population increase: In recent decades the human population has experienced rapid growth and increased mobility, resulting in intrusion into new ecological settings. This can result in exposure to new pathogens that exist in reservoirs, such as wild animals.

Human behaviour: The human host has adopted new types of personal behaviour and new food-processing and animal husbandry methods that may enhance transmission of some microbes. Modern medical treatments may result in immunosuppression, thus increasing susceptibility to pathogens. There is also the potential for the use of microbial agents as weapons of terror. Some emerging diseases are also on the rise due to factors such as lifestyle and nutrition, for example obesity and diabetes.

Preparedness and response

The first component of response against an emerging disease is recognition. The key to recognising new or emerging infectious diseases, and to tracking the prevalence of more established ones, is surveillance. An effective surveillance program can detect unusual clusters of disease, document its geographic and demographic spread, and estimate the magnitude of the problem. It can also assist with identifying factors responsible for the emergence, facilitate laboratory and epidemiological research, and assess intervention efforts.

Poor surveillance leaves policymakers and medical and public health professionals with no basis for developing and implementing policies to control the spread of infectious diseases. Many experts believe that the impact of HIV could have been limited if there had been an effective global infectious disease surveillance system in place in the late-1960s and 1970s.

After recognition of an emerging disease comes intervention – or response, recovery and prevention. The degree of intervention will determine the final impact of an emerging disease on the public's (or a product's) health. Effective intervention requires a coordinated effort by a variety of individuals, government agencies and private organisations. It also requires adequate capability in terms of the relevant areas of science and technology that underpin the intervention effort, and this in turn requires adequate research and training resources – including in the areas of vaccine and drug development, and in vector control. Public education and facilitating behavioural change are also essential strategic elements for preventing and controlling outbreaks of disease.

Australia's status

Historically, Australia has a proud record with regard to diseases in the livestock industry – with three devastating diseases arrested – bovine tuberculosis, brucellosis and bovine pleuropneumonia. Australia also played a pivotal role in the global eradication of smallpox, with Professor Frank Fenner making the announcement. Until the last few decades, Australia's lengthy isolation has afforded an unusually high level of protection, but the vast increase in transport and mobility of people and products has turned this strength into a vulnerability. While Australia still enjoys a relatively strong global market advantage as a producer with a ‘clean, green' image – the continued threat of pests and disease represents a huge risk to this competitive edge.

One of the first tasks asked of the participants of the 2004 High Flyers Think Tank was to complete the following matrix for the four focus health areas and rate the preparedness aspects according to a low, medium and high scale. The results indicate that, on the whole, despite some early successes, Australia is not well prepared for emerging diseases and there is significant need for improvement.

Australia's preparedness ratings matrix

* patchy (depends on agent and degree of impact) ** but question laboratory and hospital capacities

Think Tank outcomes

Gaps, actions and issues matrix
The way forward matrix

Conclusion

The world is a global village and the High Flyers Think Tank agreed that the risk of emerging disease cannot be completely eliminated from any one country. The researchers also conceded that nature is the most potent agent of terror. However, it was also unanimously agreed that science and technology are vital and can contribute to both ameliorating disease and managing the risk. As shown by both the Gaps, actions and issues matrix and The way forward matrix, there are many requirements that are well served by science in the facets of surveillance, prevention, response and recovery - with regard to emerging disease in the areas of human, animal, plant and aquatic health. The Think Tank also highlighted the high degree of overlap regarding the way forward in the four focus health areas – these universalities are outlined in The way forward matrix, which lists the top ten recommendations that emerged from the day's event.

And finally, in the words of that great scientist, Louis Pasteur, ‘The microbe will endure!'