The Flu: a Historical Killer （ 3 ）
Influenza killed up to 100 million people in 1918, and it's still a threat today

Implications for today
"One thing we know about the flu is that we can't predict it" said Dr. Julie Gerberding, head of the U.S. Centers for Disease Control and Prevention.

In part that's because occasionally the flu will change radically in what is called a "shift" and take humans by such complete surprise that a pandemic erupts. An estimated three to six shifts occurred in the 18th century, four in the 19th, and three in the 20th: the 1918 pandemic, the 1957 Asian flu and the 1968 Hong Kong flu. Because it can take six to nine months to make enough of an effective vaccine, a lethal shift that explodes around the world is what gives health authorities nightmares.

But there is a sophisticated global network to try to stop such a pandemic in its tracks. More than 80 countries and 121 U.S. cities belong to a reporting system to track flu.

And now, doctors know what causes flu, they have decades of experience with vaccines to combat it, and they even have anti-viral drugs, though those are expensive and of limited effectiveness.

A present threat
Still, as University of Washington and VeteransHospital researcher Dr, Kathy Neuzil says, "There's a lot we don't know." Where did the 1918 flu come from? Why exactly was it so deadly? Where did it go?

Public-health authorities are increasingly sophisticated, says Dr. Alonzo Plough, public health director for Seattle-KingCounty. But we're also much more vulnerable, he warns. Global warming, deforestation that puts humans in contact with new animal diseases, urbanization, population growth, air travel and shipping of food supplies around the world all make pandemics easier.

Cover your mouth, he advises. "It's a much smaller world than in 1918."

Vocabulary Focus

radically (adj) --- in an extreme manner
vulnerable (adj) --- able to be easily attacked