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by David Suzuki
SARS, BSE and West Nile aren't just making headlines, they're making
history. These diseases are truly products of our age - an age of global transport,
industrialized agriculture and global warming. And they represent the tip of the
iceberg in terms of emerging diseases.
Humans today are pushing every conceivable ecological boundary. We are displacing
animal habitats, feeding meat products to herbivores, dining on exotic predators
and doing it all while rushing madly about the planet in cars, boats and jet airplanes.
We are everywhere and meddling in everything. As a result, we are being exposed
to "new" diseases that have never before infected humans.
Look at SARS. It now appears this latest disease epidemic may have originated
in civet cats - a small, wild, nocturnal mammal that happens to be considered
a delicacy in southern China. Humans may have become infected when these animals
were slaughtered for food.
That sounds disconcertingly familiar to another global disease epidemic that has
now killed nearly 20 million people worldwide - AIDS. HIV, the virus believed
to cause AIDS, is thought to have been spread to humans from chimpanzees through
the bushmeat trade. AIDS has taken a tremendous toll in Africa. In the next 17
years, some 55 million Africans are expected to die from the disease.
And there's more. Earlier this spring, a Dutch veterinarian became the first
human to succumb to the highly pathogenic avian influenza that has been ravaging
poultry farms in the Netherlands. About 100 other people also contracted the disease,
which forced authorities there to slaughter more than 18 million chickens. The
disease has also spread to pigs, which are ideal virus incubators and can act
as intermediaries for a virus to spread from other animals to humans.
Four years ago that happened when Malaysian pig farmers hacked into forests to
make room for their farms. Fruit bats that used to live in the forests began to
roost in barns and building rafters. Their droppings, which carried a virus called
Nipah, contaminated the pigs' feed. Although the virus appears to be harmless
to bats, it causes a brutal cough and often death in pigs. From the infected pigs,
the virus soon spread to farm workers, who developed similar symptoms. More than
100 people died and authorities had to slaughter more than a million pigs.
Closer to home, West Nile virus, which is spread by mosquitoes, killed 284 people
in the United States last year and infected thousands more. West Nile only appeared
in the US.in 1999, and has since spread to most states and Canadian provinces.
Some experts say that global warming may have been a factor in the spread of West
Nile, as recent droughts have encouraged the proliferation of the type of disease-carrying
mosquito that prefers shallow, organically rich pools of water.
Hantavirus, Ebola and Hendra are just a few other new diseases to recently emerge
in humans. In fact, in the past 30 years, more than 35 new infectious diseases
have been diagnosed. Deaths from infectious disease in the US are now double what
they were in 1980. And three quarters of all these emerging diseases have jumped
from animals to humans.
Experts say that we are entering a new age of infectious disease and it's
largely due to human activities. When we push deep into forests and jungles, we
expose ourselves to new diseases. When we practise intensive livestock farming
and feed herbivores to herbivores, we create ideal conditions for the spread of
disease. As we change the climate, we create new vectors for disease to spread.
The growth of international trade and travel further increases the capacity for
diseases to flourish.
Some of these factors we cannot change. But some we can. We can work to end the
bushmeat trade in Africa and Asia. We can curtail the continued destruction of
our forests. We can enforce better livestock practices. We can reduce the fossil
fuel emissions that are causing global warming. Indeed, these are steps we must
take if we want a healthier future.
To discuss this topic with others, visit the discussion forum at www.davidsuzuki.org.
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