The potential for an avian flu pandemic is something were
constantly asked about at the American Council on Science and
Health. It doesnt help that headlines constantly blare about
deadly outbreaks in Asia and Europe without troubling to clarify
whether the outbreaks are deadly to humans or birds. Still, unlike
so many health scare stories we analyze, bird flu is not just hype
but a real potential threat the tricky part is determining how big
that potential is.
The major uncertainty is whether the relevant bird flu
virus, H5N1, which is already devastating flocks in Asia and Europe,
will mutate into a form that has a similarly devastating effect on
humans. Right now, bird flu can kill humans under rare
circumstances, such as when people are in close, frequent contact
with raw duck blood, or other conditions highly unusual in
developed countries and unusual even in undeveloped ones that
increase the odds of transmission from birds to humans.
But to devastate human populations in the way that it
has bird populations, H5N1 would have to mutate into a form that
spreads easily between and among humans rather than just from birds
to humans. Currently it does not appear to spread from human to
human, and several changes would have to occur in the genetic code
of H5N1 for it to do so.
In the meantime, though every death is tragic, bird flu
has taken a relatively small toll in human lives. The World Health
Organization has reported a total of 175 known cases of human
infection with H5N1, all among people working in close contact with
infected domesticated birds. Of those, 95 have
died.
Compared to the daily toll from smoking, car crashes,
or countless other killers, those numbers are minuscule but there
are a few important reasons that we cannot heave a sigh of relief:
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Roughly 54 percent of those humans who have become infected
with H5N1 have died, a disturbingly high fatality rate that
may not bode well if the disease begins spreading rapidly
among humans.
The infamous flu pandemic of 1918-1919, which killed tens of
millions of people around the world, is believed to have
originated as a bird flu a reminder that we are especially
susceptible to diseases that do not normally occur in mammals
and to which we therefore have little immunity.
It is difficult to prepare in advance for a possible bird flu
pandemic, because we wouldnt know the exact nature of the
virus were fighting until the dreaded mutations occurred that
made it easily transmissible between humans.
Despite all these reasons for concern,
defensive measures are being taken: research into new antiviral
drugs possibly one that target parts of the viruss genetic code
unlikely to alter as it mutates; the development of faster
production methods for churning out a vaccine if a pandemic occurs;
and the stockpiling of Tamiflu and Relenza, existing antivirals that
may help reduce the severity of symptoms for those who catch bird
flu, though their likely efficacy is a subject of debate.
While our best hope is that the feared mutations to
H5N1 simply never occur, it is wise to be prepared for the small but
real possibility, given what history teaches us about the potential
magnitude of such a pandemic. At ACSH, we strongly and frequently
advise against wasting resources on minimal or purely speculative
threats, but this is one case where the consequences might be
devastating enough to make a heavy investment now reasonable.
As of the end of February, human cases of bird flu were
believed limited to southeast Asia, Turkey and Iraq. In bird
populations, though, the disease had quickly spread to South Korea,
Vietnam, Japan, Thailand, Cambodia, Laos, Indonesia, China,
Malaysia, Russia, Kazakhstan, Mongolia, Turkey, Romania, Croatia,
Ukraine, Iraq, Nigeria, Azerbaijan, Bulgaria, Greece, Italy,
Slovenia, Iran, Austria, Germany, Egypt, India, France, Hungary,
Bosnia-Herzegovina, Switzerland, Georgia, and Niger.
If it reaches the United States and in birds, at
least, it likely will it is likely to appear first on the West
Coast, coming over among migratory birds from Asia to Alaska. Again,
its appearance in birds alone, or in very rare bird-to-human cases,
is not reason to panic or even to be surprised. If and when
mutations allowing human-to-human transmission occur, it will still
not be appropriate to panic. But it will time to face a potentially
devastating crisis with level-headed resolve and the best and most
technologically advanced public health resources we can muster.
Elizabeth Whelan, Sc.D., MPH, is president of the American
Council on Science and Health and serves as an adviser to theBusiness & Media Institute. ACSH has just published the report Avian Influenza,
or Bird Flu: What You Need to Know. Visit ACSH
www.acsh.org or
Health Facts and Fears
www.healthfactsandfears.com
for more information.
