Bird flu is an infection caused by a type A avian influenza virus. The virus occurs naturally among birds and is commonly found in the intestines of wild birds. It is highly contagious among birds but rarely kills wild birds. It can make domestic birds – such as chickens, ducks, and turkeys – very sick and even kill them. It has also infected pigs. People can get the virus from contact with domestic fowl and their feces.
A scientific reconstruction of the deadly 1918 worldwide flu epidemic found that it was caused by an avian influenza virus, a variant of current bird flu viruses. Several more recent flu epidemics also have had their origins in birds. In most cases, bird influenza does not cross over to humans.
Past outbreaks of avian flu often originated in places with crowded living conditions, as in southeast and east Asia, where humans, pigs, and poultry live in close quarters. Under these conditions, a virus can mutate (change) into a form that more easily infects humans.
Influenza Viruses
There is not just one kind of influenza in humans or in birds. Flu viruses are constantly changing. If you get yearly flu shots, know that the vaccine differs slightly each year to be effective against the strains of flu thought to be most dangerous that year. All influenza viruses have the ability to change. Scientists fear that the bird flu virus could change enough to be a serious risk to humans, possibly mixing with human influenza viruses.
Since 1997 there have been several outbreaks of avian flu among chickens and other domestic birds. In most cases, few if any humans were infected. The most recent avian influenza virus is a type A virus called H5N1.
Humans have little or no immunity to the bird flu viruses. Fortunately, the U.S. Food and Drug Administration recently approval a vaccine for humans against the H5N1 influenza virus.
Protect Yourself
- Get vaccinated.
- Wash your hands frequently.
- Stay home if you're sick.
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