Why avian flu pandemic is inevitable

[Guest guest]

The inevitable avian flu2-7594

By Alissa Becker/ Special To The Tab

Wednesday, June 7, 2006

When meteorologists broadcast that a noreaster is tearing towards New

England, Star Markets become clogged with frenzied shoppers stocking

up on peanut butter and Duct Tape. But when scientists warn that the

waves of a bird flu epidemic are expected to crash on the shores of

California this summer, the forecast is met with disbelief and

apathy. This lack of fear is understandable. Often we spend years

awaiting catastrophic events that never come to pass; Y2K, for

example. However, bird flu is no empty threat.

There are many environmental factors increasing the likelihood

that the avian influenza virus will spread to humans. Deforestation

shrinks habitat for the animals which are the " reservoirs " for these

viruses and increases opportunities for those animals to come into

contact with human communities. As the numbers of domestically farmed

birds increases, avian viruses that have infected farmed birds have

significantly more opportunities to infect humans. The likelihood of

a virus crossing over to humans is also increased by the very crowded

conditions in which people and domestic fowl are found in developing

countries, such as the Philippines, Indonesia, and China. Some local

customs, such as consuming the blood of domesticated birds,

cockfighting, and the widespread sale of pet birds, further increase

the potential for the virus to move into the human population. The

uncontrollable migration of wild birds from areas affected by the

virus provides yet another avenue for the virus to spread around the

world. Taken alone, none of these factors are cause for alarm, but

together they bring us closer to a pandemic.

When a bird flu pandemic develops, within a year a third of the

world's population would contract the virus. Up to 90 million

Americans would fall ill, with nine million Americans requiring

hospitalization in critical care units for respiratory distress.

Between 200,000 and two million Americans would be expected to die.

Laurie Garrett of the Council on Foreign Relations has stated that

the only thing that could exact " a larger human death toll would be a

thermonuclear war. "

In some respects, the avian influenza virus and the HIV virus

that causes AIDS are similar; both originated in non-human hosts. HIV

began as a virus affecting species of monkeys before it mutated and

became capable of infecting humans. Similarly, the avian influenza

virus is normally limited to infecting birds, but on rare occasions

it changes slightly so that it is able to infect humans. As both

these viruses originated in animals, the human immune system lacks

any exposure- and thus immunity- to them, so they can lead to human

epidemics, with high mortality rates. (Other familiar, deadly

diseases that originated in animals include Lyme disease, West Nile,

dengue, and ebola.)

The avian influenza virus and the HIV virus are not alike in all

respects. The most important distinction is that, while AIDS is an

epidemic that will likely continue indefinitely, the avian flu is a

pandemic that is expected to last only eighteen months. In this short

period of time, however, avian flu will kill more people in its first

twenty-five weeks than AIDS has killed in its first 25 years.

Most scientists agree that a pandemic is inevitable. The only

thing that has kept the bird flu from spreading human-to-human is a

protein on the virus' surface, which acts much like a key to open up

cells for invasion. Currently the virus has a " protein key " which

only unlocks birds' cells and a handful of unlucky humans' cells. To

infect millions of humans and cause an epidemic, the virus needs only

to change this one protein so that it fits into the " locks " of human

cells. The virus could randomly mutate until it happens upon the

right key, or it could acquire a protein key from the influenza virus

that is already adapted to humans. With the high frequency of human-

domestic fowl contact in Southeast Asia, the avian influenza virus is

provided with many gene-altering encounters with the human influenza

viruses.

Although the bird flu virus is currently rarely transmissible

from birds to humans, once in possession of the proper protein, it

will easily spread from human to human. Unlike HIV, which can only be

spread through exchange of certain bodily fluids, the bird flu virus

can be spread with a mere sneeze, cough, or handshake. Because

symptoms take several days to develop, it is impossible for airports

to screen for bird flu. People who don't know they are infected could

board airplanes and spread the virus around the world in mere hours.

When the virus becomes transmissible from human to human, there will

be little to impede its spread.

A bird flu pandemic is inevitable, too, because avian influenza

pandemics have occurred many times. In the past three hundred years,

there have been ten reported avian influenza pandemics, about one

every thirty years. The most lethal one occurred less than hundred

years ago, in 1918. Although often overshadowed by World War I, this

pandemic killed half a million Americans, more than the number of

American fatalities in World War I, World War II, Korea, and Vietnam

combined. The last bird flu pandemic occurred under 40 years ago in

1968, so the next one is slightly overdue.

The human population will always be plagued by diseases and

pandemics will continue to kill millions. The seeds have been sown

for another deadly avian influenza pandemic; right now, millions of

avian influenza viruses are feverishly mutating and re-sequencing

their genes in search of the perfect protein and waiting for this

virus are myriads of unchecked entrances into the human population.

We do not know exactly when this deadly virus will emerge, but we

must prepare for its inevitable arrival.

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