Quality of life and sustainable development

The central purpose of a nation should be to improve the quality of life of its people. This is not a nation’s only purpose, to be sure, but to say that it is the central purpose provides a useful framework for thinking about national priorities, including sustainable development.

Quality of life can be defined as the degree to which people enjoy (or societies provide) the living conditions (social, economic, cultural and environmental) that are conducive to total health and wellbeing (physical, mental, social and spiritual). Quality of life is both subjective and objective, as much a matter of how people feel about their lives as about the conditions in which they live.

Focusing on quality of life (or wellbeing) leads to a different perspective on sustainable development. Most importantly, it draws attention to the social dimension, which has been relatively neglected in a debate that has emphasized the economic and environmental aspects of sustainability. To the extent that quality of life has featured in discussions about sustainable development, the focus has been on future generations. A quality-of-life perspective changes this emphasis by acknowledging the important ways in which sustainability affects present wellbeing.

More specifically, this perspective provides a new approach to what has been seen as the key challenge of sustainable development, the issue that dominates political debate: reconciling the requirements of the economy - growth - with the requirements of the environment – conservation and sustainable resource use. This challenge stems from the defining difference between sustainable development and material progress, the dominant model of human development.

Material progress regards economic growth as paramount because it creates the wealth necessary to improve quality of life: to increase personal freedoms and opportunities, and to meet community needs and national goals. Sustainable development, on the other hand, does not accord economic growth overriding priority. Instead, it seeks a better balance and integration of social, environmental and economic goals and objectives to produce an equitable, optimal and enduring quality of life for all people.

Our growing understanding of the social basis of quality of life can make an important contribution to addressing the challenge of sustainable development. It provides a means of integrating different priorities by allowing them to be measured against a common goal or benchmark: improving human wellbeing. Rather than casting the core question in terms of being pro-growth or anti-growth, we need to go beyond growth, to see that growth itself is not the main game.

There are several key aspects of the relationship between quality of life and sustainability:

1. Direct impacts of environmental changes (local, regional and global) on wellbeing (especially physical), now and in the future. The recent evidence of faster-than-expected climate change adds a powerful dynamic to this relationship; it raises the stakes enormously.
2. The escalating adverse effects of material progress on wellbeing, which sustainable development would help to address. Put another way, current social priorities and directions that are putting increasing pressure on the natural environment are also becoming more hostile to human wellbeing. What we need to do to achieve sustainable development over the long term is also what we need to do to improve wellbeing in the short term.
3. The effects on wellbeing of growing ‘apocalyptic suspicions’ about the future of the world, including the effects of environmental degradation. These suspicions impact on wellbeing both directly (in a psychological sense), and indirectly (in a sociopolitical sense) by weakening our capacity to respond appropriately to the global challenges.

Environment and health, present and future.

Environmental conditions have always been an important dimension of human health and wellbeing. Poor environmental quality is directly responsible for some 25 per cent of all preventable ill-health, especially diarrhoeal diseases and acute respiratory infections.

The Millennium Ecosystem Assessment, a major United Nations initiative involving more than 1,300 experts worldwide, provides an authoritative, up-to-date and comprehensive overview of the relationship between the environment and health in its health synthesis report. It notes that nature’s ‘goods and services’ are the ultimate foundations of life and health. These provisions range from the basic necessities of life such as food, shelter and clean air and water to less tangible, but highly valued, cultural, spiritual and recreational benefits.

Over the past 50 years, humans have changed natural ecosystems more rapidly and extensively than in any comparable period in human history, the assessment says. These changes have benefited humanity, especially by greatly increasing food production, but about 60 per cent of ecosystem services are currently being degraded or used unsustainably. The causal links between environmental change and human wellbeing are complex, being often indirect, displaced in space and time, and dependent on modifying forces.

Historically, most environmental health problems have entailed specific risks within a local context, such as pollution and contamination. However, over the past two decades the focus of environmental concerns has shifted from local and regional impacts to the way humans are now changing planetary systems and processes, with huge consequences for wellbeing. As health researchers note, we must now extend our environmental health concerns to include the sustaining of natural systems that are the prerequisite to human survival, health and wellbeing.

Large-scale threats, whose effects are already being felt, include:

• Climate change: While some health impacts would be beneficial (such as milder winters), most are likely to be adverse. These include more frequent and extreme weather events such as heat waves, storms and floods; the altered range, seasonality and intensity of vector-borne infectious diseases; changes to food yields, especially of cereal crops, which are likely to increase in temperate zones but decline in the tropics and subtropics; and inundation and salinisation resulting from rising sea levels.

• The degradation and over-exploitation of natural resources such as land, water, fisheries and forests: all have implications for human health through their impacts on food production and nutrition.

• Ozone depletion: This remains a problem because of the lag between phasing out ozone-depleting chemicals and the recovery of the ozone layer. Depletion is increasing ultraviolet radiation, which is expected to increase sunburn, skin cancers and various eye disorders; it could also impair the immune system and affect global food production.

• Changes to global cycles of elements such as nitrogen, phosphorus and sulphur: the result of increased use of synthetic fertilisers, burning fossil fuels and other practices, these changes are affecting water quality and soil fertility, and so could impair global food production.

• Biodiversity loss: this poses hazards to human health through restricting supplies of food and pharmaceuticals, both of which benefit from access to new plants and animals and their genes. Another potential hazard is the risk of unravelling functional ecosystems, affecting processes such as pollination and pest control.

• Chemical contamination of food and water: for example, low-level exposure to some industrial and agricultural chemicals may be disrupting endocrine function, undermining disease resistance and reproduction.

• Introduced ‘alien’ or ‘invasive’ species: these can affect food yields and storage, produce food-borne toxins and spread infectious disease.

The Millennium Ecosystem Assessment warns that the dual trends of growing exploitation of ecosystem services and the generally declining condition of most ecosystems are unsustainable. There is an increasing risk of ‘non-linear changes’ in ecosystems, including accelerating, abrupt and potentially irreversible changes. Ecosystem changes may occur on such a large scale as to have ‘a catastrophic effect on human health’.

The environmental health literature has focused on the more direct, physical health implications of environmental change – famines, natural disasters and epidemics of infectious disease, for example. However, the social consequences of environmental change and degradation also include growing flows of environmental refugees and escalating conflict over diminishing resources. Ecological losses, embedded in a mosaic of social, economic and political factors, could cause the failure or collapse of entire societies - on a local, regional, continental or even global scale - so magnifying hugely their health costs.

Material progress and quality of life

We pursue material progress in the belief that, overall, it makes life better. A quality-of-life perspective on sustainability encourages us to look more critically at the assumed relationships between wealth and wellbeing that underpin current strategies. It shifts the focus from means to ends.

The social basis of wellbeing is much more complex, and often less tangible and material, than present approaches assume. Of particular importance is the mounting evidence that money and what it buys constitute only a part of what makes for a high quality of life. And the pursuit of wealth can exact a high cost when it is given too high a priority – nationally or personally – and so crowds out other, more important goals.

There are several streams of evidence, some admittedly indirect and circumstantial, that demonstrate the extent to which material progress is undermining quality of life:

• Diminishing returns to rising income: Comparing nations, increasing income confers large benefits to wellbeing at low income levels, but little, if any, benefit at high income levels. Life expectancy levels off at a per capita income of about US$5,000, and happiness at about US$10-15,000. Life expectancy is continuing to rise in most countries, but this is only partly due to greater wealth; happiness has not increased in recent decades in rich nations even though people have become, on average, much richer.
  
  Looking at the relationship between income and wellbeing within countries, the rich are both healthier and happier than the poor, especially in poorer countries but even in rich nations. However, the relationship is strongest at low incomes, where money improves living conditions and alleviates hardship. Above this level, wealth has symbolic value as a measure of social status, and status affects wellbeing through the social comparisons it defines. So income-related differences in wellbeing will persist no matter how much average incomes rise as a result of economic growth.

• Adverse health trends: Young people’s lives reveal most clearly the tenor and tempo of the times. While their health, measured by life expectancy and mortality rates, continues to improve, and most say in surveys that they are healthy, happy and satisfied with their lives, adverse trends in young people’s health range across both physical and mental health problems, and from relatively minor but common complaints such as chronic tiredness to rare but serious problems such as suicide.
  
  Growing numbers of children and youth are overweight or obese, placing them at risk of a wide range of health problems later in life, including diabetes, heart disease and some cancers. A fifth to a third of young people in western societies today are suffering significant psychological distress at any one time; they are experiencing higher levels of mental health problems than older people, and carrying this increased risk into later life. Estimates of the prevalence of a more general malaise (frequent headaches, stomach aches, sleeplessness) reach 50 per cent.

• Trends in personality and other psychological qualities that affect wellbeing: US researchers have analysed psychological tests of children and youth spanning over forty or more years and found marked increases in trait anxiety (or neuroticism), self-esteem and extraversion, while sense of control over life had declined. They say the findings show that broad social trends - not just genes and the family environment, as psychologists have assumed - are important influences on personality development. They link these changes to increasing individualism and declining social connectedness. Anxiety and lack of control are associated with diminished wellbeing; even high self-esteem, once regarded as a source of wellbeing, is now seen as problematic by many psychologists.

• The direct effects of sociocultural factors on health: Material progress is intimately associated with the cultural qualities of individualism and materialism. The costs of individualism (placing the individual at the centre of a framework of values, norms and beliefs) relate to a loss of both social support and personal control, and include: a heightened sense of risk, uncertainty and insecurity; a lack of clear frames of reference; a rise in personal expectations, coupled with a perception that the onus of success lies with the individual, despite the continuing importance of social disadvantage and privilege; a surfeit or excess of freedom and choice, which is experienced as a threat or tyranny; increased self-esteem, but of a contingent or narcissistic form that requires constant external validation and affirmation; and the confusion of autonomy with independence or separateness.
  
  Materialism (the pursuit of money and possessions), research shows, seems to breed not happiness but dissatisfaction, depression, anxiety, anger, isolation and alienation. People for whom ‘extrinsic goals’ such as fame, fortune and glamour are a priority in life tend to experience more anxiety and depression and lower overall wellbeing - and to be less trusting and caring in their relationships - than people oriented towards ‘intrinsic goals’ of close relationships, personal growth and self-understanding, and contributing to the community. In short, the more materialistic we are, the poorer our quality of life.

• Public perceptions of quality of life: Studies over the past decade, both qualitative and quantitative, reveal levels of anger and moral anxiety about changes in society that were not apparent thirty years ago. They show that many people are concerned about the materialism, greed and selfishness they believe drive society today, underlie social ills, and threaten their children’s future. They yearn for a better balance in their lives, believing that when it comes to things like individual freedom and material abundance, people don’t seem ‘to know where to stop’ or now have ‘too much of a good thing’.
  
  A growing proportion of Australians believe quality of life is declining despite a decade-and-a-half-long economic boom that has seen sustained, strong economic growth, declining unemployment, low interest rates and rising incomes. Indeed, some studies make explicit the tension between public concerns about quality of life and the political emphasis on economic growth.

• People’s views of the future of society, the world and humanity: Futures studies across many countries consistently reveal, in people’s expected futures, concerns about the pace of life, loss of community, too much consumerism, and destruction of the natural environment. Preferred futures, perhaps revealing humanity’s evolutionary and historical origins, emphasize closer-knit communities, more conviviality and intimacy, human-scale settlements and technologies, and a clean, healthy environment.
  
  A recent survey offered Australians two positive scenarios of the future: one focused on individual wealth, economic growth and efficiency, and enjoying ‘the good life’; the other emphasized community, family, equality and environmental sustainability. Asked to choose which scenarios came closer to the future they both expected and preferred, 73 per cent expected the former, but 93 per cent preferred the latter.

These lines of evidence show that the costs of material progress to wellbeing are not just material and structural: increasing inequality, job stress and insecurity, family pressures and environmental degradation, for example. They are also cultural and ethical: material progress depends on the pursuit of individual and material self-interest that, morally, cannot be quarantined from other areas of our lives. The patterns and trends in wellbeing cannot be regarded as unfortunate side-effects of a model of progress whose effects remain largely beneficial. Instead they need to be seen as a direct and fundamental consequence of how we currently define and pursue progress.

Suspicions of the Apocalypse: the psychosocial dynamics of global change

The widespread perception that quality of life is declining is significant, regardless of whether it is ‘factually’ or ‘objectively’ true. The resulting erosion of faith in society and its future influences the way people see their roles and responsibilities, and their relationship to social institutions, especially government. It denies people a social ideal to believe in and a wider framework of meaning in their lives, so increasing the psychological ‘load’ on personal expectations.

This dimension of the relationship between sustainable development and wellbeing is virtually ignored in both the scientific literature and political debate, but is extremely important. Environmental changes such as global warming are feeding growing apocalyptic suspicions about the century ahead. This pessimism impacts directly on individual wellbeing, but also has wider, indirect implications for wellbeing through its influence on how societies respond to this century’s challenges.

One reason this factor deserves greater attention is that our perceptions of the future are increasingly shaped by the images of global or distant threat and disaster to which people are exposed: earthquakes, hurricanes, floods, disease pandemics, terrorist attacks, genocide, and famine. While these hazards are not new, previous fears were never so sustained and varied, nor so powerfully reinforced by the immediacy and vividness of today’s media images. This effect seems certain to intensify as global warming and other threats begin to impact more deeply on our lives.

Our responses to this situation involve subtle and complex interactions between the world ‘out there’ and the world ‘in here’ (in our minds). At an individual level, for example, adaptability, being able to set goals and progress towards them, having goals that do not conflict, and viewing the world as essentially benevolent and controllable are all associated with wellbeing. Future visions would certainly affect the last, and may well bear on the other qualities, such as setting and attaining congruent goals. The loss of faith in the future may also affect wellbeing by reinforcing materialism and individualism.

At a societal level, we are being drawn in at least three directions by the prospects of dramatic, even catastrophic, social, economic and environmental changes. These responses highlight how people, individually and collectively, can react very differently to the same perceptions of threat and hazard. They are:

1. Apocalyptic nihilism: the abandonment of belief – thinking and acting as though ‘it’s a late hour in the day and nothing much matters any more’; the focus is on ‘tending our own patch’; politics is driven by fear and self-interest; decadence rules.
2. Apocalyptic fundamentalism: the retreat to certain belief – in the extreme, ‘end time’ thinking, where global war and warming are embraced as harbingers of the Rapture and Christ’s return to Earth; politics is framed as a contest between good and evil; dogma rules.
3. Apocalyptic activism: the transformation of belief – the desire to create a new conceptual framework or system (stories, values, beliefs) that will make a sustainable future possible; politics is reframed according to a new worldview and ethic; hope rules.

All three responses are growing in social intensity, a head-to-head contest that, sooner or later, will shatter the status quo. Nihilism and fundamentalism represent maladaptive responses to threat, whatever their short-term or personal appeal. Because they do not address the root causes of a problem, they risk amplifying the costs to human wellbeing. Such strategies have led in the past to the collapse of societies confronting environmental strains. Activism is an adaptive response, closely associated with the drive for sustainable development.

Conclusion

I have argued that the associations between sustainable development and quality of life embrace three different, important dimensions: the direct effects, current and projected, of environmental change on human wellbeing; the adverse effects on wellbeing associated with the current model of material progress (which sustainable development would address); and the psychosocial effects of global environmental change on both individual wellbeing and societies’ capacity to respond adaptively – and so move towards sustainability.

Put another way, a quality-of-life perspective on sustainability means looking at not just the relationships between the physical environment and wellbeing, but also those between economic, social and cultural conditions and quality of life. While wellbeing is not the only consideration, it may be critical to achieving a real public and political commitment to sustainable development. Wellbeing provides an important framework for integrating and reconciling different social goals and priorities to achieve the goal of a high, equitable and lasting quality of life.

Richard Eckersley has written extensively about progress and wellbeing, including a book, ‘Well & Good’ (Text Publishing, 2004, 2005). He is a director of Australia 21 Ltd and a visiting fellow at the National Centre for Epidemiology and Population Health at the ANU.

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Contents
1. Life before vaccination
2. The early history of vaccines and vaccination
3. An outline of the human immune system
4. Types of vaccines and currently registered members in each class
5. Are vaccines safe ?
6. Are vaccines effective ?
7. Some difficult infectious agents; emerging and re-emerging diseases
8. The future
References

1. Life before vaccination

In his book, Guns, Germs and Steel, Jared Diamond describes the history of civilisation over the last 13,000 years (1). A major feature was the great effect of infectious diseases on the survival of individuals, groups and even nations. If exposed to a disease epidemic when setting off to fight a battle, an army might not even make contact with the enemy due to the death of many soldiers. As people migrating from the Middle East settled in Europe and kept groups of animals such as cattle, the animal infectious agents over time (c. 10,000 years) adapted to humans, increasing the human death rate. In time when some travelled and discovered Mexico, North America and even Australia, the mortality rate in indigenous populations due to the introduction of infectious agents could be as high as 50 per cent so that within 100 years, the indigenous populations had decreased by up to 90%. Even 100 years ago, families often included many children because it was expected one or more would die from an infectious disease. That pattern would soon begin to change.

2. The early history of vaccines and vaccination

Smallpox is a terrible virus disease, killing about 40 per cent of a naïve population. But at least, survivors never had a second infection. It was found some centuries ago that if a person was infected via a small scratch in the skin, a process called variolation, the mortality decreased by up to 90 per cent. The real breakthrough came in the second half of the eighteenth century when it was realised especially in the UK that milkmaids escaped smallpox disease because of an earlier mild infection acquired from cows. In 1796 in Gloucestershire, Edward Jenner injected the eight year old James Phipps, with cowpox and later deliberately with smallpox (2). The boy was completely protected, and so began the current era of 'artificial' immunisation. At that time, there was no understanding of how vaccination worked

A few vaccines became available in the early twentieth century but most were made and used after the 1950s and are still being designed this century (2).

3. An outline of the human immune system.

There are two components – The innate system which exists in most multicellular organisms, and the adaptive system which is only found in vertebrates. It was originally thought that in vertebrates, these were quite separate and unrelated systems but it soon became apparent that they complement one another.

The innate system

The most important property of this system is that it comes into operation as soon as an infection is initiated or foreign material gains entrance to the body. It contains a number of cell types including dendritic cells, natural killer (NK) cells and macrophages. These cells secrete soluble factors, some called cytokines which can react with and influence other cells. Anti-bacterial factors also occur in many mucus membranes and the skin. Phagocytic cells such as macrophages, can take up and destroy foreign material including proteins especially if they had become linked to some of a group of factors called complement. In some situations, infected cells may be recognised and killed by NK cells. Another cell type, dendritic cells (DC), are most important because they ‘present’ foreign antigens to an important cell of the adaptive system, T lymphocytes, which are then activated and make very important protective responses. The DCs possess some special receptors which can recognise ’foreign patterns’, such as molecules in a bacterial extract. When some bind to one of these receptors, the DC is activated and becomes a very effective presenting cell, resulting in a powerful immune response.

The adaptive immune system

Towards the end of the eighteenth century, it was found that when a person was infected by viruses or bacteria, new proteins were formed and found in the blood. On transfer to another person, they would prevent infection by the same virus or bacterium. They were called antibodies and were formed by lymphocytes, a cell type which is a major cellular component in lymph vessels feeding into lymph nodes. Antibody prevents infection by binding to the relevant antigen on the surface of the infecting agent and so prevents it from entering cells Some antibody proteins could be very large, e.g.,IgM, M Wt 900,000). Most types such as IgG, (lymph nodes), IgA (formed and secreted at mucosal surfaces) and IgE are smaller, M Wt 150,000). For many years, it seemed as though these different antibodies could be made by B lymphocytes (B, coming from bone marrow) without any help from other cells. Then in the early 1960s, an Australian immunologist, Jacques Miller, found by chance that if he removed the tiny thymus gland from a day old mouse, the mouse would die from infectious diseases because it now made a very poor immune response. He showed that the tiny thymus was the source of another class of lymphocytes (3), T cells which ‘helped’ B lymphocytes make IgG, IgA, IgD and IgE antibodies. Meanwhile, it had become clear that B lymphocytes made a very wide range of antibodies with different specificities which would bind antigens. In 1957, Macfarlane Burnet published the completely novel but astonishing proposal that an individual B lymphocyte made antibody of a single specificity (The Clonal Selection Theory, 4). It took ten years to show this was correct and Burnet was honoured at the First International Congress of Immunology.

A critical finding was that after becoming active ‘effector’ cells, B or T lymphocytes could in a few weeks convert to become memory cells which had a very long life and could be quickly re-activated by a second similar infection to become effector cells again. The basis of all current vaccines to date is to make sufficient antibody of the appropriate specificity to prevent or greatly minimise an infection.

As well as making ‘helper’ T lymphocytes, the thymus makes another cell type, the cytotoxic T lymphocyte (CTL, or killer T cell) which, during an infection, can rapidly recognise and kill infected cells in the body. Like antibody formation, some ‘helper’ T cells are necessary for the formation of active CTLs. When infected by an agent for the first time, the sequence of formation of these immune cells in the body is first helper T cells, then CTLs and finally antibody. Often, CTLs can control and then clear the infection before sufficient antibody can be made to do this..

4. Types of Vaccines and currently registered members in each class

The first part provides pertinent information about the different types of vaccines.

(i) Live attenuated microorganisms - The virus or bacteria are treated in different ways so they lose their ability to cause disease (ie., attenuation), but retain the ability to infect cells, to produce progeny and to induce a strong immune response, including both antibody and CTLs. Most such vaccines are highly effective.

(ii) Inactivated whole virus/bacteria - The agent is treated so that it is no longer infectious. Often a larger dose must be given to induce sufficient antibody, and usually, CTL formation does not occur.

(iii) Subunit and conjugate vaccines - Antibodies that block infectivity of viruses or bacteria recognise only surface antigens, either proteins or largely carbohydrate. There is increasing interest in isolating such preparations for use as a vaccine against the whole infectious agent because they would probably cause very little side-effects. While the immune system recognises proteins and peptides very well, carbohydrates are poorly recognised. Some bacteria take advantage of this by coating their external membrane with carbohydrate and they are particularly dangerous for very young children. A complex made by isolating the carbohydrate and attaching it to a protein, called a conjugate vaccine, is much more efficient at inducing anti-carbohydrate antibody.

Other than those delivered by a vector, most viruses and bacteria infect via a mucosal membrane, eg., the respiratory tract, the gut. In contrast, many vaccines are delivered by injection. One advantage of this method is that the recommended dose can be more accurately administered. Combinations of some vaccines are used as this limits the number of injections. Great care is taken to make sure each component works well.

A list of currently available viral and bacterial vaccines is presented in Table 1. Two early carbohydrate vaccines are not listed because the corresponding more recent conjugate vaccines are far more efficient. For example, within one year after the introduction of a Neisseria meningitidis serogroup C conjugate vaccine in the United Kingdom in 1999, the incidence of meningitis in young children and teenagers was reduced by more than 90 per cent.(5 ).

5. Are vaccines safe ?

Safety and efficacy are the two crucial properties of any vaccine. Of course, a vaccine would not be used unless it was effective in preventing disease following a later exposure to the ‘natural’ infectious agent. But a high effectiveness would count for little unless it was also very safe. For example, the first rotavirus vaccine released in the USA was highly effective but was found to induce a significant side effect, intussusception (collapse of the intestine, requiring surgery), at a rate of about 1/10,000. immunisations. The vaccine was promptly withdrawn. Members of anti-vaccination lobbies maintain that many vaccines are unsafe. For example, when a second dose of MMR containing the measles vaccine was introduced in the late twentieth century, there was an increase in cases of autism in young children at about the same time. Anti-vaccination groups claimed the increase in autism was caused by the increased use of the measles vaccine. Up to ten different specialist committees subsequently showed there was no relationship between the two events. Similarly, there is no clinical or scientific evidence that any vaccine causes a specific allergy, asthma, multiple sclerosis or the sudden infant death syndrome (5).

During testing, a new product undergoes three clinical trials of increasing size which it must pass before it can be considered for registration or licensing. For those with concerns about vaccine safety, the Commonwealth Department of Health issues documents answering the many myths like the above made about immunisation.(6).

6. Are vaccines effective ?

Many countries keep records of the use of vaccines in their population. The USA has a particularly detailed record and the data for the incidence of some diseases, before and after immunisation are given in Table 2. The data for measles is very impressive. From 1913 when records were first kept, there was never less than 100,000 cases each year and an epidemic occurred about every three years as groups of susceptible babies and infants became available for infection. This stopped dramatically in the 1960s when the vaccine was introduced. After the introduction of a second dose of vaccine at the turn of the century, transmission in the USA of this highly infectious agent stopped. Clinical cases of the disease in the country subsequently are due to infected visitors.

The data in Table 2 show that immunisation is one of the most successful achievements of medical intervention (7). A personal experience is telling. In recent years, I have lectured on this topic to over 800 final year high school students. When asked whether a young brother or sister has died from an infectous disease, not one has said - yes. In contrast, when I was very young, tuberculosis and meningitis claimed two out of five of my cousins.

7. Some difficult infectious agents; emerging and re-emerging diseases.

There are about eighty Infectious agents, including about ten parasites, which can cause disease in humans (7). Apart from those in Table 1, attempts to make vaccines are being made against most of the remainder, and many are likely to be successful. There are some which have resisted all attempts to date, even for as long as forty years. The three which are the most important are the human immunodeficiency virus (HIV, which causes AIDS), the bacterium, Mycobacterium tuberculosis and the parasite, Plasmodium, which causes malaria. Each has learnt how to evade the different components of the immune response, in part by developing great antigenic variation.

HIV is one of about ten emerging diseases, infecting humans recently for the first time.(8 ). West Nile virus is now called a re-emerging virus. Confined to Africa for centuries, it has recently reached and spread across the USA.

8. The future

New Vaccines.

Among a long list of vaccines being developed, some of the agents causing the diseases are potentially highly dangerous. Among the viruses are Bird flu (H5N1), Dengue, Epsteim-Barr, Hepatitis C, HIV, and Respiratory Syncytial viruses; among the bacteria, Haemophilius ducreyi (an STD),Helicobactor pylori and Neisseria gonorrhea; and among the parasites, Malaria, Filariasis, Schistosomiasis and Treponema pallidum (syphilis).

New approaches to immunisation

(i) Chimeric live vectors. Some DNA in a viral or bacterial vaccine is deleted, and replaced by DNA coding for one or more antigens from a disease agent. A strong immune response is made to the inserted antigen(s).

(ii) Immunising with DNA coding for an antigen seemed attractive. Though it worked well in mice and monkeys, it gave poor responses in humans.

(iii) A new approach, the prime/boost concept is promising. DNA coding for an antigen is inserted in two different live vectors. The host is primed with one chimeric vector and the response then boosted with the other chimeric vector. The results to date are promising.

(iv) An infectious virus inactivated by exposure to gamma irradiation, still gives a strong antibody and CTL response, potentially a very safe technique.

Cancer - The prospects for controlling/curing cancer. Cancers grow because they have learnt how to evade the immune response. A viral infection causes some – e.g., hepatitis B virus and liver cancer, papilloma virus and cervical cancer, and these cancers have been prevented by vaccinating against the virus. It is a very different story with the other cancers. It is a very active field, using antibodies, CTLs or pre-activated dendritic cells to induce a strong immune response. A major difficulty is to find antigens which are specific to the cancer cells so that vaccination would not harm other cells. Prostate cancer cells have carbohydrate side chains specific for those cells, so this is a promising lead. But overall, progress is slow.

Table 1.

Table 2. Vaccine efficacy (percent decrease in the incidence of different infectious diseases) in the USA, as assessed by comparing maximum morbidity levels before vaccine availability and the levels some years after compulsory vaccination was introduced.

*During a major epidemic, **Calculations based on 2002 figures. Dates in parenthesis indicate the year the vaccine was widely introduced. MMR vaccine was introduced in 1971. IPV (Salk) vaccine in 1952 and OPV (Sabin) in 1963.

References

1. Diamond,J. Guns, Germs and Steel. A Short History of Everybody for the Past 13,000 years. Vintage, London. Pp 1-360, (1992).
2. Plotkin, S. L. & Plotkin, S. A. (In; Vaccines, Fourth Edition, Eds. Plotkin, S.A.& Orenstein, W.A., Elsevier,USA. Pp.1-15.
3. Miller, J. F. A. P. Immunological function of the thymus. Lancet, ii. p.748 (1961)
4. 4. Burnet,F. M. A modification of Jerne’s theory of antibody production using the concept of clonal selection. Aust. J. Sci.,20, 67-68,(1957)..
5. Ramsay, M. E., Andrews, N., Kaczmarski, E.B., Miller, E. Efficacy of meningococcal serogroup C conjugate vaccine in teenagers and toddlers in England. Lancet, 357,195-6 (2001).
6. Hall, R. Immunisation. Myths and Realities" responding to arguments against immunisation.A ust. Govt. Publishing Servie, Canberra. 1-17. (1996)
7. Ada, G. L.& Isaacs, D. Vaccination; the facts, the fears, the future. Allen & Unwin, Sydney. Pp. 1-241,(2000).
8. Fauci, A,S, Vaccines and the challenge of emerging and re-emergng diseases, rom HIV/AIDS to bioterrorism. In; Vaccines, Preventing disease, Protecting Health.(de Quadros, C. A. ed) Pan American Health Organisation, Washington, DC. Pp. 1-12. (2004).

Gordon Ada Until retirement Gordon Ada was Professor of Microbiology at the John Curtin School of Medical Research at the Australian National University, where he is now a Visiting Fellow. He writes: "Trained initially as a biochemist, I switched first to virology and then to immunology. This provided a good background to become involved with the Vaccine and Vaccination Programmes of the World Health Organization (1960 -91). I have maintained this interest ever since and have written two books and many reviews on these topics. Vaccination is now regarded as one of the most effective of all public health initiatives especially in developed countries, as shown by the very low current mortality rates of young children compared to early last century. The situation in most developing countries is also improving."

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Contents
Introduction
Important discoveries: the causes of infectious diseases
Important discoveries: prevention and treatment of infectious diseases
Infectious diseases in hunter-gatherer societies
Infectious diseases after the industrial revolution in the nineteenth century
The second half of the twentieth century
The future
Further reading

Introduction

To keep this essay brief yet relevant, I will concentrate on infectious diseases in Australia, going global only for the period since World War II. First, however, we need to consider when causes and cures of infectious diseases were discovered.

Important discoveries: the causes of infectious diseases

Infectious agents - For most of recorded history the cause of infectious diseases was a mystery. It was not until the ground-breaking discoveries of Louis Pasteur and Robert Koch in the 1860s that it was realized that many infectious diseases were caused by bacteria. Thirty years later, use of Pasteur-Chamberland filters, which held back bacteria, demonstrated that other infections were caused by much smaller objects, later called viruses. Other infectious agents included rickettsias, fungi, protozoa, and nematodes; several species in each of these groups cause disease in humans.

Important discoveries: prevention and treatment of infectious diseases

In 1854, when cholera was still attributed to a miasma, John Snow founded the science of epidemiology by demonstrating that "the cholera poison" was distributed widely by the Broad Street pump, which drew sewage-polluted water from the River Thames. Then, a hundred years after Edward Jenner had, in 1798, demonstrated that inoculation with cowpox virus provided protection against smallpox, vaccines were developed against typhoid fever, cholera and plague, followed in the early twentieth century by vaccines against yellow fever, pertussis, influenza and typhus. Several other vaccines have been developed since, an enormous effort is being made to produce vaccines against malaria and HIV.

Effective treatment of compound fractures and other localized infections was initiated by Joseph Lister in 1864 by the use of carbolic acid as an antiseptic. However, it was not until the 1940s when Howard Florey converted the serendipitous discovery of the antibacterial properties of penicillin into practical reality that the antibiotic era was initiated, with control of many bacterial diseases.

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Infectious diseases in hunter-gatherer societies

It is impossible to say, with any certainty, what infectious diseases occurred amongst hunter-gatherers before contact with humans who had experienced the agricultural revolution. The best information, and it is largely guesswork, comes from a consideration of infectious diseases amongst Australian Aboriginals before 1788. One can say, with confidence, that hunter-gatherers would have been infected from time to time with whatever arboviruses that cause disease in humans occurred in the areas where they lived. Some 75 arboviruses have been isolated in Australia. Only half a dozen of these cause human disease, the most important being Murray Valley encephalitis virus, Ross River virus and Kunjin virus. Since malaria has long been present in New Guinea, which was connected by land with northern Australia when Aboriginals arrived some 50,000 years ago, it was also very likely to have been brought to northern Australia, where vector Anopheles mosquitoes have long been present. Other vector-transmitted diseases that occurred amongst Aboriginals, most commonly in northern Australia, include three different rickettsial diseases (North Queensland tick typhus, scrub typhus and Q fever), and a nematode transmitted by mosquitoes, filariasis.

However, because the population numbers in different tribes were so small, none of the infectious diseases common in Europe in the eighteenth century; diphtheria, measles, scarlet fever, whooping cough, smallpox, tuberculosis and probably chickenpox, were endemic among the Aboriginals, although smallpox was introduced several times into northern Australia by Macassan trepang fishermen between about 1720 to 1860. Evidence from bones suggests that two treponemal diseases were present before 1788, yaws in the humid north and 'irkintja' (treponarid), a non-venereal disease, in the southern part of Northern Territory. One interesting finding in the 1960s was the widespread occurrence of hepatitis B virus, which is spread by intimate postnatal contact between mother and child and can persist for life and be maintained in very small populations, causing hepatitis in adult life in some of those affected.

Trachoma has long been common among Aboriginals; the early English explorer, William Dampier, mentioned seeing Aboriginals on the north-west coast in 1688—89 who "had such bad eyes that they could not see us till we came close to them".

Infectious diseases after the industrial revolution in the nineteenth century

Apart from nutritional problems, infectious diseases were by far the commonest diseases of humans in the industrialized countries in nineteenth and early twentieth centuries, as they are now among the poor in developing countries. They covered the full range of infectious diseases except those limited to tropical countries. To get and idea how Australia was developing then, as a number of British colonies, Sydney was established in 1788,within the colony of New South Wales, Hobart, in Van Diemansland, in 1803, Perth, in Western Australia, in 1829, Adelaide, in South Australia, in 1936 and Brisbane and Melbourne, still within the colony of New South Wales, in 1824 and 1835 respectively. Because of the relatively small numbers of children and the length of the voyages from Britain, none of the common infectious diseases of childhood occurred in the colonies until many years after the arrival of the First Fleet.

Among specific diseases, the first death from diphtheria, which had been unusually common and severe in England in 1858, was reported in Melbourne in October 1858 and it was the cause of death of 280 children there in 1859 and 636 in 1860. It appears to have been imported into Tasmania in 1859 and Western Australia in 1864, but whether from England or another Australian colony is impossible to say. The first definite case of scarlet fever was reported in Tasmania in 1833, with cases in Victoria and New South Wales in 1841, Queensland in 1858 and South Australia in 1859. Whooping cough was introduced into Sydney in 1828, and was very prevalent in Tasmania in 1833, whence it was transferred by a military detachment to Perth and was common there in 1848. Measles was introduced into Victoria in 1850, and spread to New South Wales the same year and to Tasmania in 1854. Influenza was recorded in Sydney for the first time in 1820, when a virulent epidemic attacked both Europeans and Aborigines. Thereafter there were epidemics in Sydney in 1826 and 1836, and in Sydney, Melbourne and Hobart in 1847, coinciding with years of world prevalence of the disease.

As clean water, the proper handling of sewage, antisepsis, and the use of vaccines and antibiotics became available over the next century, they were immediately applied to the control of infectious diseases in Australia, with the result that by the mid-1950s such diseases were of minor importance to the white population of Australia, although not amongst Aborigines.

The first discoveries of world-wide significance made by Australian scientists were the discovery of the adult worm of Filaria bancrofti by Joseph Bancroft in 1876 and the demonstration of its development in mosquitoes by his son, Thomas Bancroft, who also suggested, for the first time, that Aedes aegypti was the probable vector of dengue. Then, around the turn of the century, bubonic plague broke out in Sydney and Brisbane, and Frank Tidswell, Ashburton Thompson and Burnett Ham made some astute observations on the role of fleas in its epidemiology. In 1918 J.B. Cleland, later Professor of Pathology in the University of Adelaide, isolated the virus of "X disease", an arbovirus later known as Murray Valley encephalitis virus, from the brains of fatal cases obtained after an outbreak in New South Wales.

In the latter half of the nineteenth century bacterial intestinal diseases in Australia had the same patterns of morbidity and mortality now seen in Third World countries. Deaths from typhoid fever were in excess of 50 per 100,000 per annum, cholera cases were not infrequent and few people escaped the unpleasant, sometimes life-threatening consequences of bacillary dysentery and salmonella gastroenteritis. Between 1900 and 1950 the incidence of these diseases declined dramatically, due primarily to better education and increasing affluence which led to clean water supplies, effective sewage and waste disposal and improved housing, together with an increasing awareness of the importance of personal hygiene and the value of community-funded health facilities.

In 1915 a donation from Walter Hall, who had made a fortune from gold mining at Mount Morgan, was used to set up the Walter and Eliza Hall Institute, which rapidly became, and continues to be, 90 years later, the outstanding medical research institute in Australia. It really did not get going until Charles Kellaway became Director in 1923 and in 1928 appointed F.M. Burnet, who was to become the most innovative and brilliant biological research worker in Australia, as a full-time research worker. Initially he worked on bacterial viruses, then on animal virology and eventually on immunology.

The 1930s saw the development of effective microbiology laboratories in most large hospitals and the expansion of Departments of Microbiology in the universities. Initially building on discoveries made in the northern hemisphere, these led to greatly improved diagnosis and later to real advances in the understanding of bacterial and later viral diseases. In 1941 Norman McAlister Gregg, an ophthalmologist, discovered the teratogenic potential of rubella virus, a discovery described by Burnet as "the most important contribution to medicine ever made in Australia."

The second half of the twentieth century

With accelerating pace, this period saw unprecedented advances in science and technology, great increases in wealth in the 'Western' industrialized countries, great increases in air traffic all over the world and the advent of globalization. Although deaths from infectious diseases, particularly of children, remained and remains high in the developing countries, the global population continued to expand, from 360 million in 1900 to 2.5 billion in 1959, 6.2 billion in 2000 and an expected 8 to 9 billion in 2100. Industrialization, air pollution and greenhouse gases continue to expand, with dire warnings about global warming and gross overuse of resources. Especially in Africa and Asia, there is ever-increasing pressure of expanding populations on remnant forest areas, leading to increasing contacts between humans and other animals, with the appearance of what are called "emerging" diseases. A great advance in curative medicine for bacterial diseases was initiated with the development of penicillin in the early 1940s, but now we are seeing, increasingly, a "re-emergence" of various bacterial diseases due to antibiotic resistance. The classical emerging viral disease is HIV-AIDS, first impacting on public consciousness as a disease of homosexual men in the United States in the mid- to late-1970s. It is now the most common and widespread lethal infectious disease in the world, although control in Australia has been remarkably good.

The term "emerging viruses" became widely used after a conference with this name organized in Washington by Joshua Lederberg in 1989. It is estimated that some 35 viral diseases of humans discovered during the last twenty years fall into this category. In 1995 the Center for Disease Control and Prevention (CDC) initiated the production of a peer-reviewed journal, Emerging Infectious Diseases, initially (1995—98) quarterly, then every two months (1999—2001) and since 2002 monthly. This is free on the web and paper copies are distributed free to interested scientists world-wide.

The future

During the last decade or so it has come to be accepted that human health world-wide cannot be separated from the health of the rest of the biosphere, or indeed from the "health" of the inanimate environment. With the reality of global warming, resource destruction and growing population, contact between wild animals and humans is going to increase. Every domestic animal that has been adequately studied is host to viruses of between 10 and 28 different genera (and some of these containing at least that number of antigenically different species). There is no reason to think that wild animals are any different, and with ever-increasing contacts between human and wild animal populations more emerging viral infections are inevitable.

With bacterial diseases we are becoming aware of the myriad of ways by which resistance genes can be transferred from one microorganism to another, for example with MRSA Escherichia coli O57, to know that this is what the future has in store for us. The other feature of the modern world, and the future, unless shortage of fuel interferes with air transport, is the fact that any disease transferred from one person to another via the respiratory tract can spread around the world in a matter of days. Influenza is a bird virus with a genome consisting of eight pieces of RNA; its infectivity depends on one of the surface proteins, the haemagglutinin. RNA viruses undergo much more frequent mutations than DNA viruses, and in addition, the eight genome fragments can re-assort, the phenomenon that caused pandemics in 1957 and 1968. So far, of the 15 different haemagglutinins found in wild birds only three (H1, H2 and H3) are able to pass from one human to another via the respiratory tract. Currently there is great concern that a strain of influenza virus that is unusually virulent for a wide range of different birds, and occasionally infects children, may acquire the ability to spread readily from one person to another via the respiratory tract, either by continuing mutation of its haemaglutinin (H5) or by reassortment. With the enormous increase in intercontinental air travel such a virus would cause a severe pandemic.

Further reading

Burnet, F.M. (1971). The Walter and Eliza Hall Institute, 1915—1965. Melbourne University Press.

Cumpston, J.H.L. (edited by M.J. Lewis) (1989). Health and Disease in Australia. A History. Australian Government Printing Service, Canberra.

Fenner, F. (ed.) (1990). History of Microbiology in Australia. Australian Society for Microbiology.

Flannery, T. (2005). The Weather Makers. The History and Future Impact of Climate Change. Text Publishing, Melbourne.

Hackett, C.J. (1978). Treponematoses (yaws and treponarid) in exhumed Australian Aboriginal bones. Records of the South Australian Museum, 17, 275-405.

Morse, S.S. (1993). Emerging Viruses. Oxford University Press, New York.

Webb, S. (1995). Palaeopathology of Aboriginal Australians. Health and Disease across a Hunter-Gatherer Continent. Cambridge University Press.

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Anthony J McMichael

Contents
"Sustainability" and population health
Climate change and health
Heatwaves
Infectious diseases
Implications for society at large
References

During 2006, Australians and people everywhere have begun to engage increasingly, and with growing concern, with the issue of human-induced global climate change. This is, by any criterion, an extraordinary phenomenon – in terms of its very nature (fancy the human enterprise now being of such dimensions that it is changing the way the planet works), its scale, the rate at which it is now evolving, and the diversity of its impacts.

Climate change is part of a larger syndrome. Contemporary phenomena such as global climate change, ecosystem disruption and the growth of massive modern metropolises pose great new challenges to our capacity to maintain satisfactory, health-supporting, environmental and social conditions. These environmental changes and their attendant health risks are of both unfamiliar scale and great complexity – and one aspect of unfamiliarity and complexity is that they are looming as major determinants offuturepopulation health. They are casting ever-longer shadows over future generations (McMichael, 2001; Raven, 2002; WHO, 2005).

Environmental health research has traditionally studied the effects of localised exposures to specific direct-acting agents (such as heavy metals, pesticides, ionising radiation, or microbes in local food or water). Today, though, we face a manifestly different category of environmental health hazard – one that occurs on a larger scale and impinges on health predominantly via systems-based changes to the environment (including climate, food-producing systems, freshwater circulation and ecosystem "goods and services").

The huge, escalating, global problem of climate change is now widely recognized. The basic science is no longer contentious. Climate scientists foresee a rise in average Earth’s surface temperature of several degrees centrigrade this century (Figure 1). Note also the rapid rise in temperature of approximately 0.5^oC since 1975. More than four-fifths of this rise has been attributed to human actions that have affected atmospheric gaseous composition (IPCC 2001).

Figure 1.
Estimated variations in Earth’s average global surface temperature since 1000 AD, with the modelled likely range of increased temperature over the coming century in response to the ongoing build-up of atmospheric greenhouse gas concentration. Graph based on data from Intergovernmental Panel on Climate Change (IPCC, 2001).

Increasingly, this forecast is looking like an under-estimate – climate conditions and related phenomena (extreme events, ice melting, ocean current shifts, etc.) are changing considerably faster than was foreseen a short decade ago.

These larger-scale systemic risks to population health are a fundamental signal that humankind is now on a non-sustainable path. The following sections explore: (i) the (fundamental) relationship of population health to sustainability; (ii) several aspects of the relationship between large-scale human-induced changes to natural environmental systems and human health; and (iii) identify some of the associated challenges to researchers.

"Sustainability" and population health

There is an urgent need for us to examine therationale, the purpose, of our striving for "sustainability". In my view, the primary (and unashamedly anthropocentric) reason for our concern about non-sustainability is because today’s generally adverse trends in environmental conditions, ecosystem functioning and non-renewable resource management have huge, and growing, implications for human wellbeing, health and (in some parts of the world already) survival. This is not to discount the important and moral obligation that we humans have to sustain as much of this planet’s (wonderful) natural systems for their own sake – but, frankly, it is also a matter of absolute self-interest for us, as a species.

The Wikipedia defines sustainability as a system that seeks to achieve "parallel care and respect for the ecosystem and the people within". As many scientists and other writers are now making clear, human society, its economy and the psychological and biological wellbeing and health of its members depend absolutely on the natural environment and its life-support systems. The Swedish Parliament has recognised this crucial linkage. Of the five fundamental principles underpinning their Environmental Objectives (1999), the first-listed is "Promoting human health".

This, unfortunately, is an all-too-rare example of enlightened understanding as to why human societies need, today, to take action to achieve environmental/ecological sustainability. Indeed, much of our day-to-day discussion of "sustainability" focuses on achieving a balance between environmental conditions, social conditions and economic productivity. This is now widely referred to, misleadingly, as "the triple bottom line". However, those three entities are actuallymeans; they are notends. Again: the true objective of our achieving a sustainable way-of-living is to ensure the continuation of good and equitable experience (both biological and social) for humans.

Human wellbeing and health ought, then, to be the central criterion of sustainability. "Ecological sustainability" is not just about maintaining the flows from and into the natural world that sustain the economic engine nor maintaining iconic species and iconic ecosystems. It is about maintaining the complex systems that support health and life.

Climate change and health

Human-induced climate change is just one part of a much larger problem of "global environmental change". The human enterprise, in aggregate, is now placing unprecedented pressures on the biosphere, and is beginning to cause systemic changes. As we destabilise the climate system and disrupt climate-sensitive natural systems, we inevitably incur adverse health risks – directly and indirectly, now and increasingly in future. Some health benefits may occur in some locations. However, any such benefits will be the (perhaps temporary) exceptions.

Climate change and its environmental and social impacts poses a range of risks to health. The possibilities include impacts of heatwaves and other extreme weather events, changes to air quality, the geography and seasonality of various infectious diseases, effects on local food yields, freshwater supplies, the general vitality of ecosystems and the flow of "services" from them, and the underpinning of diverse livelihoods.

The risks to health arise via very diverse pathways. Consider the problems of climate change and the anticipated reduced rainfall in much of Sub-Saharan Africa. If farming families have no crops to sell because of drought, the risks from HIV and AIDS will rise yet further when women and children are forced to abandon drought-desiccated land and make their living, often as sex workers, in cities.

In Australia the main types of anticipated health impacts are:

• The impacts of thermal stress (esp. heatwaves) on serious illness events and deaths
• Physical and other hazards from extreme weather events (floods, fires, storms and droughts)
• Changes in geographic range, season and incidence of various infectious diseases
• Social and mental health problems in rural communities affected by falling farm yields
• The diverse health consequences of increased immigration/refugee flows in Asia-Pacific region

In general, climate change will not cause exotic new health disorders. However, it will alter the probabilities of many familiar risks to health. Figure 2 shows three types of causal pathways: (1) direct; (2) those mediated by changes in natural systems; and (3) those due to social, economic and demographic disruption.

Figure 2.
Climate change and health: The three main pathways of risks to health.

Examples of the first two pathways are: (1) heatwave-related deaths and (2) the climatic influences on the occurrence of mosquito-borne infectious diseases.

Heatwaves

As the world warms and as regional weather patterns become more variable, there will be more frequent and more intense heatwaves (and, probably, more variable patterns of storms, floods and cyclones). Heatwaves place great physiological stress on people, especially if the heat is sustained overnight (as in inner-urban areas especially) and if the event lasts for more than just several days. Most of the deaths occur in the frail, elderly, sick and very young.

The 2003 heatwave in Europe was a major killer, extreme in both its duration and temperature. It extended over much of western Europe. The 12-day heatwave caused an excess of approximately 35,000 deaths during the event. In Paris, the average daily temperature was about 12 degrees C above the usual August average for much of the heatwave. An estimated 900 excess deaths occurred in Paris during the event.

Infectious diseases

Many infectious diseases are sensitive to climatic conditions, particularly insect-borne infections and those spread person-to-person via contaminated food and water. Globally, malaria, dengue fever, cholera, and food-borne infections are of particular concern. There have been several recent scientific reports that suggest that recent climate change has already influenced some infectious diseases. These include the northwards extension of tick-borne encephalitis in Sweden over the past two decades, associated with warming winters; and the ascent of highland malaria to higher altitudes in some parts of eastern Africa.

The risks to population health from climate change pose a challenge for health-impact researchers., because it is difficult to tease out the various factors.

For example, malaria may have moved to higher altitudes in eastern Africa. Is this due to the warming that accompanied it – or is it due to changes in land-use, population movement, cessation of mosquito control programs, or the emergence of anti-malarial resistance? A tough question.

Of course, the causal pathways are not as simple as suggested by Figure 2. Many non-climate modulating influences affect climate-related health outcomes – such as material standard of living, population growth and demographic change, public-health infrastructure, access to healthcare and quality of healthcare. This raises the possibility of near-term adaptive strategies to lessen adverse health impacts. Adaptation includes actions, planned or unplanned, such as public education, the use of protective technologies, vaccination programs, disease surveillance, monitoring, use of climate forecasts and health-impact forecasts, and development of emergency-management and disaster-preparedness programs.

One further comment is very important, here. In addition to attempts at ‘holding-operation’ adaptation strategies, true primary prevention of the risks to health requires substantial abatement of global greenhouse gas emissions. While individuals, families and communities should contribute to the collective effort to abate emissions, the climate change problem is so large and systemic that only government-led mitigation, including via internationally agreed targets, emissions limitations and carbon trading, and penalties for non-compliance, will ensure that climate change is slowed and, hopefully, arrested.

Estimating Future Health Impacts in Australia

We have recently carried out a series of preliminary studies of climate-and-health relationships in Australia, and have used these, and other published results, to estimate likely future health impacts occurring in response to CSIRO’s climate change scenarios for 2020 and 2050.

The main findings were that the following changes in health risks would be likely to occur:

1. Increased summer-time deaths from heat extremes in all major cities.

These estimated increases will be a function of increased thermal stress affecting an ageing (more susceptible) population. On average, in each city there would be several hundred more deaths annually (assuming no increase in actual population size). In several countries (e.g. UK), estimates show that decreases in winter mortality due to milder winters may partly/fully compensate for increases in summer mortality. In Australia, heat-related deaths are unlikely to be much offset by cold-related averted deaths.

2. Southwards extensions of the mosquito-borne of dengue fever (see diagram below) and malaria.

In order to contain any such spread, public health surveillance and control measures would need to be extended into these at-risk regions. The size of the population at risk increases, and the costs of control would escalate commensurately.

Dengue Fever: Estimated geographic region suitable for maintenance of Ae. aegypti, under alternative climate scenarious for 2050

NCEPH/CSIRO/BoM/UnivOtago, 2003

3. Increased risk of diarrhoeal disease, in summer, and especially in remote/rural communities. For example, we estimated a 15% increase in diarrhoeal hospitalisations in Aboriginal children living around Alice Springs by 2020.

4. Increased mortality and injury risk from inland floods, with increased health impacts expected in parts of Queensland, NSW and Victoria, and reduced impacts in SA and WA.

Note that the above estimation of future health impacts is based on climate change scenarios limited to changes inmeanclimate conditions. Increasingly it appears likely that changes in climate variability that will accompany climate change, especially changes in frequency, intensity and location of extreme events, will have greater health and other impacts than will changes in mean conditions.

Environmental refugees

As demographic and environmental conditions deteriorate in vulnerable regions, there will be increased immigration and environmental refugee pressures on neighbouring (especially richer) countries. This will be accompanied by the diverse adverse health consequences that typically affect displaced persons – and, perhaps, their hosts.

The UN’s latest assessment of this knock-on effect of climate change and other large-scale environmental changes is rather alarming. Within the next two decades there could be as many as 50 million people displaced by environmental deterioration. Sea level rise, floods, desertification and land degradation have already contributed to large out-migrations. In the Pacific, with rising seas, the small population of the Carteret Atoll has recently been relocated, and the island population of Tuvalu is planning to do likewise. A recent report by the CSIRO (2006) has underscored the rapidly increasing likelihood and substantial scale of this international moral, economic and geopolitical problem – of an increase in the numbers of displaced and refugee persons.

Implications for society at large

Globally, the emerging situation poses more than an environmental problem; it poses a political and moral problem in that the great majority of the greenhouse gas emissions to date have come from today’s developed countries, whereas most of the adverse health risks, by dint of population location and vulnerability, occur in developing countries. Sub-Saharan Africa, hugely dependent on rain-fed agriculture and already widely impoverished, under-fed and ravaged by infectious diseases (especially HIV/AIDS, tuberculosis, malaria and child diarrhoea), is especially vulnerable to the environmental and social stresses of climate change (especially the expected decline in rainfall).

True primary prevention must depend on a massive international effort to curtail greenhouse gas emissions and, hence, climate change. This looms as a huge and unprecedented international challenge – and, as yet, few countries are making a serious effort to help slow the process. Australia has been one of the slowest of the developed countries to make a commitment to genuine internationalism in this matter.

No matter what degree of international commitment is achieved over the coming decade, the world is already committed to at least another half-to-one degree centigrade rise in average surface temperature. This reflects the enormous inertia in the climate system and the associated slow redistribution of excess energy (heat) throughout the world’s oceans. Therefore, every country needs now to also take secondary preventive action – that is, to identify the main health risks confronting their population, the most vulnerable sections of the population, and the appropriate interventions to reduce those health risks.

The threat of serious illness and death due to extremes of heat can be reduced by simple, immediate measures – such as early warnings for such events (by meteorology agencies), special provision for (or attention to) the elderly and sick, and public education about clothing, staying indoors and household ventilation. However, to render communities more ‘heatwave-proof’ in the longer term will require wider-ranging and farsighted changes to urban layout, transport systems, housing design, and the nurturing of green space.

Whether in Australia or elsewhere, it will be important for government and community to think in imaginative and multi-sectoral fashion about how to modulate living environments, physical infrastructure, ecosystem management, social institutions and public information flows in order to achieve more resilience against the shocks and stresses of climate change.

The task, and indeed the moral responsibility, of our generation is to achieve mid-course corrections that will steer the biosphere back to a life-supporting state able to sustain the wellbeing and health of future human generations.

References

Australian Institute of Health and Welfare (AIHW).Australia’s Health. 2006.Canberra: Commonwealth Department of Health and Ageing, 2006.

IPCC (Intergovernmental Panel on Climate Change).Climate Change 2001: The Scientific Basis. Contribution of Working Group 1 to the Third Assessment Report of the Intergovernmental Panel on Climate Change.Cambridge. Cambridge University Press, 2001.

King M. Health is a sustainable state.Lancet1990; 336: 664-7

McMichael AJ, Ranmuthugala G. Global Climate Change and Health. In: Kawachi I, Wamala S (eds).Globalization and Health.Oxford: Oxford University Press, in press.

McMichael AJ, Woodruff R, Hales S. Climate change and human health: present and future.Lancet, 2006; 367: 859-69.

McMichael AJ.Human Frontiers, Environments and Disease. Past patterns, Uncertain Futures.Cambridge: Cambridge University Press, 2001.

Millennium Ecosystem Assessment (MA).Ecosystems and Human Well-Being: current State and Trends. Hassan R, Scholes R, Ash, N (eds) Vol 1, 2005, p 2.

Raven PH. Science, Sustainability, and the Human Prospect.Science2002; 297: 954-7.

Sen A.Development as Freedom. New York: Anchor Press, 1999.

World Health Organization.Ecosystems and Human Well_Being.Health Synthesis. Geneva: WHO, 2005.

World Health Organization.Preventing Disease Through Healthy Environments.Geneva: WHO, 2006 http://www.who.int/quantifying_ehimpacts/publications/preventingdisease/

Tony McMichael is Director of the National Centre for Epidemiology and Population Health at the Australian National University, Canberra. Originally from Adelaide, he was during 1994-2001 Professor of Epidemiology at the London School of Hygiene and Tropical Medicine, UK. His main epidemiological research interest is in studying environmental influences on human health. Since 1993 he has played a central role in the scientific assessment of health risks for the UN's Intergovernmental Panel on Climate Change (IPCC), and has played a corresponding role in the recently-completed international Millennium Ecosystem Assessment Project (2001-2005). He has been an advisor to WHO, the UN Environment Program, and the World Bank on health risks from environmental exposures and global environmental changes. Within the Earth System Science Partnership of the International Council of Science he co-chairs the newly-launched international research network on Global Environmental Change and Health. He has authored several books, including most recently Human Frontiers, Environments and Disease: Past Patterns, Uncertain Futures (Cambridge University Press, 2001), and (as senior editor) Climate Change and Human Health: Risks and Responses (WHO/UNEP/WMO, 2003).

tony.mcmichael@anu.edu.au

This paper as a [512KB pdf]

Definitions, scope and perspectives
Common diseases and associated characteristics of modern civilisation
Un-met universal health needs in modern civilisation

Towards a healthy and biosensitive society
References

Definitions, scope and perspectives

The Oxford Dictionary defines diseases as disorders of structure or function in the human body, especially those that produce symptoms. Boyden (2004) uses the term civilisation to encompass all human societies with economies based on farming (i.e. ecological phase 2, 3 and 4 societies).

Should modern civilisation be defined as a period of time—such as the Second World War to the present? Should it defined by geography—for example, so-called western civilisation? Should it defined by culture—including access to modern technology? Should it be defined from a bio-historical perspective as ecological phase 4 (Boyden, 2004)? For the purposes of this paper, I will define modern civilisation as societies with the characteristics of ecological phase 4—the high-consumption phase of human civilisation. Some people in every country on Earth (whether living in the East, West, North or South) currently live in this way.

It is not possible to provide a comprehensive overview of diseases of modern civilisation in this short paper. Hence, I will use selected diseases as exemplars, linking these diseases to un-met universal health needs (see our paper Our place in nature).
The health perspectives through which we will explore this are the evolutionary health principle and western, or science-based, medicine. The intention is not to give western medicine undue priority as a health philosophy, rather to acknowledge that this perspective will be meaningful to many readers of these papers. Certainly, there are alternative ways of thinking about human health and wellbeing—including Ayurvedic medicine, traditional Chinese medicine, Aboriginal bush medicine. We should be open to learn from, and with, these other ancient philosophies.

Common diseases associated with modern civilisation (the high-consumption phase)

A list of common diseases and associated characteristics of modern civilisation is presented in Box 1. The list focuses on a sub-set of the universal health needs—those un-met for many people in modern societies.

Box 1

Common diseases and associated characteristics of modern civilisation

The information presented in Box 1 is a simplification. It is important to understand that medicine often defines diseases in accordance with the organ system affected. This works well when the condition is confined to one organ system (e.g., primary lung cancer). Of course it’s not always this straight forward. Our modern way of life is affecting multiple organ systems at the same time. Diabetes (or metabolic syndrome) is a good example – it is the classic lifestyle disease and can affect every organ system.

Un-met universal health needs in modern civilisation

The associations identified in Box 1 are discussed below (readers may also like to refer to the reference list if they seek additional information). The discussion is organised around un-met universal health needs.

1. Lack of physical activity

One of the universal health needs (physical) identified in our paper Health and civilisation is (reproduced here for convenience):

A pattern of physical activity which involves some short periods of vigorous muscular activity and longer periods of medium (and varied) muscular activity, but also frequent periods of rest.

Our modern way of life is less physically active than ever before. For many people work is very sedentary. It is done at a desk, with the assistance of telephone and email for communication. Recreation has also become increasingly sedentary. Since the advent of television and video games, many people now take their recreation sitting in front of these screens. Transport is also less active. The availability of cheap motor car transport has transformed the way we move in our environment, and at the same time, has transformed the shape of our cities.

A wide range of labour-saving devices are now available to assist with household chores and work. This has been positive as it has reduced the physical demands of such work, and associated injury and disability. At the same time, it has reduced levels of physical activity at the population level. We no longer use somatic (food) energy for these tasks. We have replaced this somatic energy with energy from fossil fuels.

Lack of physical activity is associated with a wide range of diseases and other health problems – obesity, heart disease, diabetes, high blood pressure, osteoporosis, depression.

2. Unnatural diet

Another universal health need is:

The food culture in some modern societies has become a fast-food culture. Increasing numbers of people use convenience foods to minimise the time required to source and prepare food, and to maximise time available for work and leisure. These convenience foods are often high in fat and salt.

A few generations ago, most lollies were sold in separate lolly shops. This placed a structural restriction on supply. These foods are now heavily marketed and a key source of income in grocery shops—encouraging prominent placement in these shops. Lollies and other snack foods—such as chocolate and potato crisps—are no longer considered a treat by many people. They are now part of the daily diet.

Many people, especially in high- and middle- consumption countries, have ready access to these unnatural and unhealthy foods. It can require extra effort for people in such places to source a natural diet. This unnatural diet is contributing to a wide range of diseases and other health problems—including obesity, high blood pressure, heart disease, diabetes and depression. There remains potential for micro-nutrient deficiencies, if there is not a sufficient quantity of a diverse range of different foods of plant origin and lean meat.

3. Unclean air (tobacco smoking and other sources of air pollution)

A third universal health need is clean air to breathe:

Clean air (not contaminated with hydrocarbons, sulphur oxides, lead etc.)

Tobacco smoking (purposefully) pollutes the air breathed in by the smoker, and anyone else in the immediate vicinity.
In some parts of the world, urban centres have poor air quality. Motor vehicle emissions are an important source of air pollution in cities where the motor car is a primary mode of transport. Residents in such places are exposed to a range of air pollutants, including fine particles, carbon monoxide, oxides of nitrogen, hydrocarbons, volatile organic compounds, ozone and lead.

Industrial air pollution is an important health issue in many middle-income countries. The health risks depend on the nature of the industry. Smoke from forest fires is currently an important source of air pollution in South-East Asia and other parts of the world where large-scale land clearing is underway.

Unclean air – from tobacco smoking and air pollution – is an important cause of chronic respiratory disease, heart disease and cancers.

4. Other un-met health needs

In addition to these three un-met universal physical health needs, there are some un-met universal psychosocial needs, associated with consumer culture, and alcohol and other drug use. These are less well understood, and often given less emphasis in medical practice.

The relationships between alcohol and other drug use and disease are complex. There is evidence that moderate alcohol intake is beneficial for health. Many people use alcohol in this way. Prolonged use of alcohol, at higher levels, can lead to depression. People who are already depressed (for other reasons) may also be attracted to using alcohol and other drugs because of the temporary mood altering effects of intoxication. This can exacerbate depression. Alcohol and other drug use is also associated with other diseases including liver diseases such as hepatitis, cirrhosis and cancer, and infectious diseases from risk behaviours such as needle sharing and unprotected sexual contact (hepatitis A, B, C and HIV infection).

Changes to food production, manufacturing and handling may have un-foreseen health consequences. The emergence of Esherichia coli 0157:H7 as a cause of foodborne illness in high-consumption countries provides a salutary reminder of the importance of microbial infection. Relatedly, there seems to be an emerging hygiene obsession at the societal level. One manifestation of this is the marketing and sales of myriad household anti-microbial products. Contact with natural environmental micro-organisms is a universal health need. The “hygiene hypothesis” is used to explain the higher incidence of allergic disorders in high-consumption countries.

In recent years, there have been rising concerns for the safety of children in modern societies. Some of this concern arises from the risk of pedestrian and cyclist injury from motor vehicles. Some arises from concern about “stranger-danger”. One consequence of these concerns is that many parents no longer encourage their children to spend time exploring their neighbourhood unsupervised by adults. This may well affect the social and emotional development of these children, and have future health consequences.

The relationships between consumer culture, and its association with a more secular and perhaps less reflective and less spiritual society, and health is more controversial. Popular philosophers have identified modern maladies, such as status anxiety (de Botton, 2004). And what of the impact of the 24-hour office culture, enabled by mobile phones and palmtop computers, associated with an “epidemic of insomnia”? Or the impact of lack of contact with nature?

Towards a healthy and biosensitive society

Research with indigenous Australians has shown a marked beneficial health impact of temporary reversion to traditional hunter-gatherer lifestyles on diabetes and other associated conditions (O’Dea, 1984). Perhaps, this would also apply to depression and anxiety. If people with depression were taken from their environment and lived in a different way (plenty of physical activity, healthy food, a different social context), it is plausible that they may also be cured of their depression.

Of course, this is not a practical treatment for all. The importance of this work is that it demonstrates two things—firstly, the link between the way we live and these conditions, and secondly, if we change the way we live we will not have these conditions.
I will conclude with two examples of approaches that warrant further consideration.

• We need to re-think our urban environments. In future, we should build our cities in ways that provide opportunities for plenty of physical activity in the way we inhabit our places. Certainly, it is important to allow easy access for people with physical impairments. It is possible to achieve both these objectives simultaneously.
• We should take stock of our food supply and our food “culture”. Natural food is a universal health need, and it also provides wonderful opportunities for social connection, interaction and conviviality.
  
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Last word

We already know many of the things we need to do to live in a healthy way. The knowledge was passed on to us by our grandparents and other forebears. We need to get our lives into balance (in harmony with nature); we need to take time to smell the roses; and we should do everything in moderation. These simply homilies are entirely consistent with the evolutionary health principle.

References

Boyden S. The biology of civilisation: Understanding human culture as a force in nature. Sydney: UNSW Press, 2004.
Capon AG. The way we live in our cities. Med J Aust 2007; 187: 658-661.
de Botton A. Status anxiety. Melbourne: Penguin, 2004.
McMichael AJ. Human frontiers, environments and disease: Past patterns, uncertain futures. Cambridge: Cambridge University Press, 2001.
O’Dea K. Marked improvement in carbohydrate and lipid metabolism in diabetic Australian Aborigines after temporary reversion to traditional lifestyle. Diabetes 1984; 33:596-603.