Environmental Engineering Reference
In-Depth Information
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Harvesting wild fish for a burgeoning world population has depleted
various ocean fisheries. We will need, increasingly, to rely on fish-
farming to maintain supplies.
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Injudicious antibiotic use, including for the production and
maintenance of domesticated animals and houseplants, has rendered
many pathogens antibiotic-resistant.
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Food preservation with chlorofluorocarbon-based refrigeration has
contributed to stratospheric ozone destruction.
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The powering of cities (with its undoubted health benefits) has
contributed to greenhouse gas emissions.
Overall, then, appreciation of the basic ecological significance of popula-
tion well-being and health, viewed within a larger frame and over decadal
time, will enrich our understanding of both the goals and guidelines for 'sus-
tainability'.
Let us consider in a little more detail, and within a broadly based ecolog-
ical framework, two of the above-mentioned issues: emergent infectious dis-
ease, and the health risks posed by global environmental changes, especially
climate change.
Infectious disease ecology
There has been a recent upsurge of interest in the apparent rise, or increased
adaptability, of infectious diseases. It is no surprise, for example, that our
widespread overuse and misuse of modern antibiotics has led to a general
increase in microbial antibiotic resistance. We have been putting intense
selection pressure on microbes, with these antibiotics, and they - as they
have been doing for several billion years in nature - have responded by
acquiring metabolic resistance to these otherwise lethal chemicals. With a
generation time of mere hours, it is inevitable that, among the millions of
mutant microbes produced daily, there will be some that, by random good
fortune (for the microbial species) are resistant to any particular antibiotic.
Infection is intrinsic to life on Earth. The bacteria, viruses, protozoa and
other infectious agents obtain nutrients and energy by parasitising higher
organisms. Most infection is benign, some is beneficial to both host and
microbe, and some adversely affects the host's biology - it is these that we
call 'infectious disease'. During the long processes of human cultural evolu-
tion, population dispersal around the world, and subsequent inter-popula-
