As published as an OpEd in The Hartford Courant, October 14, 2005.

Fear The Flu...

By John Shanley, M.D.

We live in a dangerous world - urban crime, 9/11, the Iraqi war, hurricanes Katrina and Rita. Even so, there is something else out there, invisible to the naked eye, with the potential to eclipse these hazards and cause human suffering on an epic scale. It is influenza, specifically Influenza A.

For most of us, influenza is hardly a cataclysmic event. We tend to think of it as an unpleasant ailment, occurring every winter, leading to lost work and, only occasionally, death. It is something we can live with. However, every 10 to 40 years a new strain of influenza appears for which none of us has immunity. As a result, the infection spreads like wildfire, infecting a majority of people in the world, causing widespread illness and a marked increase in deaths. The last wildfire, a worldwide epidemic known as a pandemic, occurred in 1968, almost 40 years ago. Frankly, we are overdue.

Where does the new strain of influenza come from? Birds, especially migratory birds, are the major reservoir for a large number of Influenza A strains. Occasionally, one of these strains adapts and can be transmitted from human to human. When the new strain spreads easily from person to person worldwide, causing high levels of illness and death, it is called a pandemic. After the new strain is widely established, it can continue to circulate for many years, but its virulence is reduced as people develop antibodies to it. It is then considered a seasonal epidemic because of its significantly lower levels of illness and death.

In 1997, a very lethal strain of Influenza A, H5N1, began to appear in domestic poultry in Hong Kong. It killed entire flocks and infected 18 people, causing 12 deaths. Fortunately, there was no sustained transmission in people, and the outbreak abated when the most of the chickens, at least 1.3 million, were slaughtered.

Last year, the avian flu reappeared in Asia. This time, it persisted and spread. In fact, it seems to have become more lethal than its 1997 cousin. The Avian flu is causing a great die-off of both domestic poultry and wild birds. It seems to be spreading throughout Asia and into India and Russia as the birds migrate. This avian flu virus seems very lethal for other animals as well. In Thailand, it killed more than 100 tigers fed infected chickens in the Sriracha Zoo in Chonburi.

To date, this avian flu has infected 112 people, with more than 50 percent dying. As yet, there has been no sustained human-to-human transmission, the last step needed for pandemic influenza.

Why are we worried? The 1918 pandemic, caused by a virulent strain of Influenza A, killed tens of millions of people worldwide. Those infected often died within 48 hours, mainly from fluid buildup in the lungs. In this country, more than half a million Americans died. The epidemic brought life in the United States to a virtual standstill. Health facilities were rapidly overwhelmed.

We don't know if history will repeat itself, but the appearance of a virus like the avian flu is worrisome. What is being done about it? For the last 10 years, the Centers for Disease Control and Prevention has been preparing for pandemic influenza. The progress of the avian flu outbreak is being carefully monitored.

State and local health programs are preparing for a widespread outbreak. The federal government is stockpiling antiviral drugs against flu. Researchers are trying to develop an effective vaccine against avian flu.

Unfortunately, we are not there yet. Flu vaccines take a long time to produce, and the virus has a nasty habit of changing, rendering the vaccine less effective. Nevertheless, the work goes on, with tools that were not available to prevent widespread suffering in 1918.

Yes, we live in a very dangerous world.

John Shanley, M.D., is professor of medicine and director of the division of infectious diseases at the University of Connecticut Health Center.