Avian influenza or "bird flu" has now caused more than 60 deaths
worldwide, with the most recent epidemic in Indonesia, where four people
have died. On a global basis, 60 deaths are not very many. So why are
health experts becoming alarmed about the H5N1 ("bird flu") virus? People
are concerned because the virus has demonstrated the ability to kill a
high percentage of the humans it infects. In addition, it has spread from
birds to many other species, which is very uncharacteristic of viruses.
The spread of infection in birds increases the opportunities for direct
infection of humans. If more humans become infected over time, the
likelihood also increases that humans, if concurrently infected with human
and avian-influenza strains, could serve as the "mixing vessel" for the
emergence of a novel subtype—with sufficient human genes to be easily
transmitted from person to person.
Once the virus acquires the capability to "go human," an influenza
pandemic (that is, a worldwide epidemic) would likely ensue in a matter of
weeks. To date, the vast majority of infections of bird flu in humans have
been acquired by close contact with domestic poultry. However, there is
one documented case of human-to-human transmission in Thailand. It remains
a curious fact that most people who have worked with poultry infected with
the bird-flu virus, culling infected birds for example, have not become
infected—a fact that no one seems able to adequately explain.
The antigenic changes (that is, changes in the exterior
proteins—Hemagglutinin and Neuraminidase) in bird and human influenza
viruses go on year after year. Annual influenza outbreaks typically do not
cause severe illness and death, because people have built up natural
immunity to the viruses over a period of years. Rapid spread of H5N1
viruses between humans, on the other hand, will led to explosive global
expansion in which everyone is at risk for infection, illness, and death
because of a complete lack of natural immunity to the virus.
Because avian influenza or "bird flu" is much more deadly than the regular
annual flu in humans, coupled with the high infectiousness of influenza
viruses in general, a bird-flu pandemic is potentially very deadly,
causing many tens—or even hundreds—of millions of deaths across the globe.
In September 2005, Dr. David Nabarro of the World Health Organization
(WHO) stated, "A new pandemic would claim between 5 million and 150
million people."
Once a flu pandemic starts, everyone will be at risk of getting pandemic
flu, because no one has natural immunity to the virus. However, certain
groups may be at greater risk of dying than others. There are strong
indications that the coming bird-flu pandemic may be similar to the
influenza pandemic of 1918 and, if so, healthy adults would be most at
risk of dying, along with pregnant women and the elderly.
Why are healthy adults at greatest risk? It appears that the H5N1 bird-flu
virus causes a massive immunological response against the virus in those
with the strongest immune systems. Unfortunately, this causes the release
of human enzymes called "cytokines," which destroy lung cells along with
viral particles. This, in turn, causes a deadly outpouring of fluids into
the lung, which interferes with the exchange of oxygen and carbon dioxide.
This reaction is frequently fatal. There are few effective treatments—one
of the only treatments available is to place the patient on a ventilator,
a mechanical respirator. Even with this treatment, patients often die from
complications.
Bradford Frank, M.D., M.P.H., M.B.A.
The Frank Group
P.O. Box 138
Lakewood, NY 14750
www.AvoidBirdFlu.com
About the author:
Bradford Frank, M.D., M.P.H., M.B.A.
The Frank Group
P.O. Box 138
Lakewood, NY 14750
www.AvoidBirdFlu.com
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