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Vaccination drive in Africa
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Global environmental change has played a significant role in the emergence, resurgence or spread of several infectious diseases of humans, plants and animals. A failure by the global community to address the root causes of disease emergence associated with human impacts on wildlife and ecosystems could have severe global consequences.
Naturally occurring microbes – including bacteria, viruses, fungi and protozoa – comprise a significant portion of wild biodiversity worldwide. In many ways, these organisms are responsible for supporting and regulating a range of key ecosystem functions, and so provide the foundation for a wide range of ecosystem services. For example, bacteria and fungi are vital to waste decomposition and nutrient cycling, driving primary productivity and affecting climatic patterns on a massive scale. Disease-causing microbes (pathogens) and parasitic invertebrates play an equally important role in ecosystem functioning and productivity, and – though it is perhaps paradoxical and an unpleasant thought – are essential to maintaining the health of ecosystems and populations of wild flora and fauna. Cycles of infection, disease, morbidity and mortality have played an essential part in natural selection and the evolution of life, and have also driven the evolution of human societies and cultures.
The relationship between biodiversity loss and the emergence and spread of new and more virulent disease organisms is of great international significance. There is clear scientific evidence that outbreaks of many diseases, including SARS, Ebola, hanta viruses, malaria, and the HIV pandemic, have resulted from human impacts on wildlife and ecosystems, including inter alia habitat disturbance, unsustainable trade in bushmeat and other country foods, and the wildlife trade. Urban sprawl, encroachment into wilderness areas, and pollution of oceans and inland waterways have also been linked with the spread of diseases of people and wildlife. The current international spread of the H5N1 strain of avian influenza and other zoonoses (diseases spread from animals to man) may also be facilitated by these activities, and it is possible that biodiversity loss and ecosystem disturbance could increase the risk of this and other diseases being transmitted to people and wildlife.
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Young birds on a goose farm
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Failure to address the root causes of disease emergence and spread associated with ecosystem change or impacts on wildlife could have severe global consequences. Therefore, it is essential that the use of biodiversity indicators and the protection of ecosystems be integrated into international efforts to protect public health and prevent the emergence and spread of infectious diseases.
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