ABSTRACT
We have to come to the conclusion that our tapping of the molecular wilderness, although yielding wonderful results on the discovery and use of molecules from nature to cure our illnesses, may not yield sustainable solutions, since the wilderness can fight back due to plasticity of life forms. Antibiotics, for example, are weapons made by microorganisms to prey on others or to defend themselves. In nature, they are not used as single agents but as parts of strategies for their interaction with their enemies or their prey. The outcome is evolution of all interacting life forms, each struggling for its own survival. In contrast, our tapping of molecules from nature has been done mostly in a simplistic manner, obtaining single drugs such as broad-spectrum antibiotics, which were then used intensively in ways which do not take sufficiently into account the plasticity of infectious organisms and their ability to fight back. Experience over the past few years has now taught us to control the use of drugs in an attempt to achieve sustainability. Even then, we now realize that each drug against infectious pathogens has a limited life time of usefulness before it is compromised by pathogen resistance. The realization that the ‘magic bullet’ does not exist should not deter us from finding the best solutions in the therapy of infectious and other diseases. The problems are complex, and solutions based on science and technology alone, powerful though they are, will not be sufficient. We need input from other areas of human knowledge. At this juncture, it may be a good idea to examine other complex problems confronting us and how we are trying to solve them so that we may learn from these efforts. 6.2 Lessons from Climate Change
One of the great global crises in our time is climate change resulting from human activities, mainly use of energy and our industrial, agricultural and household practices [103]. We have used fossil fuels as main sources of energy for an extended period, resulting in emission of carbon dioxide and other greenhouse gases, with global warming as a consequence. Our industrial, agricultural and household practices contribute to global warming, not only from the use of fossil fuels, but also in the production of other greenhouse gases, such as chlorofluorocarbons used as refrigerants and for other purposes and methane from waste. Deforestation has also
contributed to global warming since it reduces the absorption of carbon dioxide by plants. Although climate change is a natural process, over the past few decades, it has been increasingly realized that human activities have significantly contributed to it in the form of global warming. Threats from climate change include droughts, floods, sea-level rise and various other hazards. For example, climate change may increase the incidence and severity of infectious diseases due to effects on abundance and adaptive changes in vectors and pathogens. The risks from climate change therefore have to be mitigated, and we must adapt before these problems reach critical levels in the next few decades. Climate change is an issue which can offer valuable lessons in our future dealing with the molecular wilderness. For example, overreliance on fossil fuels as sources of energy is akin to overreliance on antibiotics as therapies for various ailments. Consequences such as floods, droughts and sea-level rise from climate change were largely unforeseen, although they could have been anticipated had we been more environmentally aware. Similarly, the rise of resistance of pathogens due to our use of drugs could have been anticipated from our knowledge of mechanisms of evolution. Evolution allows adaptation of life forms on being challenged by various stresses: those which cannot overcome the stress will perish, while those which can deal with the stress, for example, through genetic changes leading to drug resistance, will survive and flourish. In dealing with problems of climate change, the risks of present and future harms must be mitigated. This was done, for example, in the case of phasing out the use of chlorofluorocarbons, which are a cause of the greenhouse effect and contribute to global warming. Reliance on fossil fuels is increasingly reduced through use of solar and wind energies. Increased effort is made to reforest various parts of the world, together with attempts to reduce deforestation. Furthermore, adaptation must be made to the changes brought about by global warming, for example, by management of anticipated floods, droughts and sea-level rise. Effects on disease occurrence and severity, food production and distribution and other effects must also be made through adaptation of our present way of life and livelihood. Similarly, in dealing with the problems of drug resistance, we need to have both mitigation and adaptation strategies. The risks of
resistance can be mitigated by informed policy for drug use and public education. Increased emphasis should be made on improvement of public health and prevention efforts, including sustainable reduction of vectors, increased surveillance of diseases and status of resistance and mass vaccine administration. One way of preventing resistance from occurring is the use of drug combinations, where members of the combination have different targets or modes of action so that the chance of occurrence of resistance is diminished since it needs changes in all the targets (see Chapter 5). However, even after all the mitigation efforts, problems of drug resistance will likely eventually occur, albeit after longer time periods. We need to adapt to the resistant pathogens once they occur, for example, by finding new effective methods to detect and characterize the resistant pathogens, by changing treatment regimes to ensure efficacy, by introducing new drugs with different mechanisms of action or finding new ways to treat disease. We need to change our behaviour and lifestyle in order to avoid exposure to vectors or pathogens. To avoid exposure to mosquitoes, insecticide-treated bednets have been introduced, with very impressive results on the reduction of malaria in Africa. Chicken farming practice had to be changed in Asia and elsewhere to avoid too close contact between people and birds which posed a risk of bird influenza. The practice of eating ‘bush’ meat, that is, meat from wild animals from the forest, needs to be discouraged, not only because it encroaches on wildlife, but also because it raises the risk of zoonotic diseases. These mitigation and adaptation efforts require the tools of science and technology to come up with new drugs, diagnostics, vaccines and other means of fighting diseases. However, similar to our efforts in dealing with climate change, they also require a broader change-a transformation-in our society in order to achieve sustainable solutions. This transformation cannot be achieved only by science and technology, although they are important enabling tools. It requires change among individuals and the society as a whole regarding our outlook and values on our relationship with nature. Furthermore, we should not think of winning the battle with infectious diseases only as a medical or a public health problem separated from other problems concerning the livelihood of people, poverty, human behaviour, religion and culture. In short, we need to think of a broad, ecological approach to the problems concerning health and diseases.
