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  Avian Flu
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- Introduction - Influenza A viruses are found in many different animals, including ducks, chickens, pigs, whales, horses, and seals. However, certain subtypes of influenza A virus are specific to certain species, except for birds which are hosts to all subtypes of influenza A.
Subtypes that have caused widespread illness in people either in the past also caused outbreaks in pigs and horses.
Influenza A viruses normally seen in one species sometimes can cross over and cause illness in another species. For example in 1998 viruses from humans were introduced into the pig population and caused widespread disease among pigs.
Avian influenza viruses may be transmitted to humans in two main ways:
- Directly from birds or from avian virus-contaminated environments to people.
- Through an intermediate host, such as a pig.
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- 1918 - More than 500,000 people died in the United States and up to
50 million worldwide may have died in the 1918-1919 flu
pandemic.
An estimated 20 percent to 40 percent of the world`s population
fell ill during the worst-ever outbreak, which is thought to
have spread through troop movement in World War I.
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- China Threat - The bird flu, in its current form, is a deadly, but limited
disease. Only people who have direct contact with infected
birds have caught the disease.
The disease becomes a world-wide catastrophe if it mutates
in a way that allows it to be spread from human-to-human.
Ironically, the disease would also be much more deadly if it was
to mutate into a less deadly form. Because it kills half its victims, its spread
is, to some degree, self-limiting. If it were to kill a
much smaller percentage, say 1%, of its victims, it would be
much more likely to spread across the globe, causing far more total deaths.
The widespread presence of the bird flu in China raises
the risks of both of those
developments.
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- Media Sites -
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