Bird Flu Warnings: A "Chicken Little" Story?

Long before the financial crisis, even before the Iraq War, Americans fixated on the possibility of an avian flu pandemic. We were rattled at the prospect of a disease that quite literally fell out of the sky, and against which we had no defense. Bleak visions of global infection and plague-level fatality rates darkened the news reports.

Bird flu fear swept the nation like a fad. And, as with any trend, our attention flickered on and then off again. It's been more than two years now since avian flu last made national headlines, and we need to ask: What has evaporated—the threat, or our awareness of it?

To understand what, if anything, has changed in terms of our susceptibility to avian influenza and its spread across the globe, let's cut straight to the heart of the fear.

Birds vs. humans

The question at the core of rational concern is whether or not the bird flu virus, known as H5N1, has the capacity for human-to-human transmission. We know already that it's easily transmitted among bird populations, and that under rare circumstances it has made the jump from infected birds to humans.

But H5N1 can't yet be transmitted from one person to the next. This fact is the main source of whatever comfort scientists and epidemiologists have surrounding avian flu.

"Almost all the cases we've seen of human infection with H5N1 have been people who live in close proximity or work in close proximity to birds—chickens, for the most part," confirms Dan Epstein, information officer for the Pan American Health Organization, a regional office of the World Health Organization (WHO).

The confirmed human cases have predominantly been limited to Asian countries, with the heaviest losses of life in Indonesia, Vietnam, China, and Thailand. As of this writing, there have been no human infections west of Egypt (see map). Bird-to-human infection is a phenomenon principally in rural areas where farmers or industrial workers have direct contact with infected fowl and inhale the virus that lives in their feathers.

How lethal is bird flu?

Fatality statistics can be misleading, yet we're innately drawn to the numbers. Looking at the past five years, there have been 387 reported cases of human infection and a total of 245 deaths, according to WHO monitoring. The ratio of infections to deaths, at 2:3, testifies to avian flu's lethal power.

If you last checked that fatality statistic three years ago, when it read 79 total deaths, the current human toll may strike you as alarming. However, a better barometer on disease control is the trend, rather than the cumulative number, of reported cases. Since 2006, the numbers of H5N1 infections and fatalities have been steadily dropping.

Thanks belongs in no small part to the cooperative work of international organizations like the WHO and the Food and Agriculture Organization of the United Nations (FAO), and to the health-education programs encouraged in nations at high risk. By assiduously tracking cases in birds and humans alike, disease surveillance provides an early warning system.

"Countries are now obligated to report any event involving disease that has the potential for wide public health impact in the country or internationally. We used to joke that if a chicken dies in Laos, we know about it," says Epstein. "In countries with high numbers, like Indonesia and Vietnam, the governments have undertaken fairly extensive education programs to teach people [how to avoid infection]. When a cluster of cases arose in Egypt, they launched a huge television campaign immediately."

Knowing that watchful eyes can help prevent the spread of disease now—and provide advance warning later—is reassuring. It signals that steps have been taken to mitigate our vulnerability to a pandemic.