For more
than a century, bird flu has circulated among birds, particularly
domesticated fowl, but recent attention has been called to avian
influenza since some strains infected humans.
No longer is bird flu relegated to pigs and birds, as the virus has
strengthened and mutated, resulting in a contagion that can move from
bird to human. Human cases of bird flu have caused infections and death
across the globe as scientists struggle to identify the dangerous
strains and prevent a fatal pandemic.
We have long known that avian influenza existed in animals, often
killing wild and domestic populations. These viruses belong to related
kinds of influenza that evolve and mutate just like any virus. We used
to be primarily concerned with losing valuable birds that were providing
eggs or meat to poultry farmers. However, in 1997 that changed when bird
flu appeared to prove fatal for people in Hong Kong.
A pathogenic,
or active, strain of bird flu will kill birds quickly and spread
rapidly through a population. If a wild, migratory bird catches
the flu, it can carry it many miles to other wild or domesticated
groups.
These
viruses evolve in two ways, through drift and shift. Drift refers
to inexact replication, such that newer viruses are further from
the original genetic material, but share enough DNA that they are
still only spread amongst a single species. When a virus shifts,
it means that the genes of one virus mix, or breed, with a different
virus, usually inside a carrier. Due to shift, bird flu mixed with
a human kind of flu, and was thus able to infect humans through
direct contact with birds.
Human
cases of bird flu are incredibly alarming, and raised the concern of
virologists and government agencies in China, Hong Kong, Vietnam,
Canada, and other countries. This imminent pandemic could only be
controlled by the vast slaughter of millions of fowl to contain the
virus that spreads by air, water, and soil.
The bird flu is especially dangerous because our immune systems don’t
have any antibodies to handle something that used to be relegated to
animals. Thus, it takes hold with unprecedented force, settles in the
lungs, and resists anti-viral and anti-bacterial medication.
Most
health experts researching and fighting the incidence of human bird flu
do not have an optimistic outlook. They point out that the pathogen has
not appeared to evolve such that human-to-human contact is contagious,
yet it remains that people working with fowl, swimming in infected
rivers, playing in an area where carcasses were buried, or breathing air
near a poultry processing plant, can lead to infection.
Thus
far, doctors have been able to diagnose bird flu, identify the specific
strain, and target the proper disposal of infected birds. Yet they are
ineffective at treating the resultant respiratory infection, leading to
fatalities. They note that flu epidemics and pandemics appear to be
inevitable given the history of contagious disease over the last few
centuries.
Source: wiseGEEK
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