Background
Information
What Is a Pandemic?
As defined by the
Department of Health and Human Services (DHHS),
a pandemic is a global
disease outbreak. A flu pandemic occurs when a new
influenza virus emerges for which people have little
or no immunity, and for which there is no vaccine.
The disease spreads easily person-to-person, causes
serious illness, and can sweep across the country
and around the world in very short time.
It is difficult to
predict when the next influenza pandemic will occur
or how severe it will be. Wherever and whenever a
pandemic starts, everyone around the world is at
risk. Countries might, through measures such as
border closures and travel restrictions, delay
arrival of the virus, but cannot stop it.
Health professionals
are concerned that the continued spread of a highly
pathogenic avian H5N1 virus across eastern Asia and
other countries represents a significant threat to
human health. The H5N1 virus has raised concerns
about a potential human pandemic because:
- It is
especially virulent
- It is being
spread by migratory birds
- It can be
transmitted from birds to mammals and in
some limited circumstances to humans, and
- Like other
influenza viruses, it continues to evolve.
Since 2003, a growing
number of human H5N1 cases have been reported in
Azerbaijan, Cambodia, China, Djibouti, Egypt,
Indonesia, Iraq, Thailand, Turkey, and Vietnam. More
than half of the people infected with the H5N1 virus
have died. Most of these cases are all believed to
have been caused by exposure to infected poultry.
There has been no sustained human-to-human
transmission of the disease, but the concern is that
H5N1 will evolve into a virus capable of
human-to-human transmission.
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