Richard Knox, NPR
Motorbike traffic in downtown Hanoi — on a light day. Some riders are wearing filter masks. Crates of poultry are also occasional passengers.
HANOI — The world's pandemic flu jitters mostly emanate from here.
Of the 120 or so human victims of bird flu counted so far, three-quarters have been Vietnamese.
Why? A visit to Vietnam offers powerful clues.
This is a very densely populated country, way more than China. Eighty-five million Vietnamese live on a strip of land only slightly bigger than New Mexico.
And Vietnam is changing at warp speed. New construction is everywhere. Shops overflow with electronics, fancy plumbing fixtures and floor tiles, overstuffed furniture, shiny motorbikes — even in provincial towns. Drive through those provincial towns at night, when wide ground-floor doors are open to the breeze, and you see wide-screen TVs pulsing in the most modest houses.
But Vietnam is still a country of ancient agricultural practices. Outside cities, most households still keep chickens and ducks.
This is a culture with a strong preference for fresh-killed meat. In the countryside, people slaughter and pluck poultry in their dooryards. In cities and towns, you practically stumble over sidewalk butchers in the act of draining the blood from just-purchased chickens and ducks.
Consider this: Up to 70 percent of the ducks in Hanoi's so-called "wet" markets — street markets that sell live animals — harbor H5N1. But the virus doesn't kill them or make them sick. Lately Vietnamese scientists have discovered that chickens can be silently infected, too; they carry the virus but show no symptoms.
Take all these factors and mix them up. In fact, that's what happens every day. Traffic between countryside and city is incessant. Nearly everybody here, it seems, has a motorbike — a far cry from the not-so-long-ago days when bicycles predominated.
Many of those motorbikes are piled high with crates of live chickens, ducks and piglets. The traffic will be especially intense early next year during the Tet festivities, when Vietnamese return to their home villages and tradition literally dictates a chicken in every pot.
The H5N1 virus is widespread in birds throughout Southeast Asia, but Vietnam has had far more human cases than its neighbors. Doesn't Thailand have the same mix of factors? What about Cambodia or Laos? Well, no. Those countries are not so densely populated. Thailand's poultry industry is more centralized. Laos and Cambodia are poorer and have less city-country mixing. And these days southern China's poultry industry resembles America's sanitized factories far more than Vietnam's traditional ways.
In a way, it's reassuring more Vietnamese haven't been sickened and killed by H5N1. Maybe that means the virus won't make the leap from a virus that mainly infects birds to one that can spread easily among people. But no one can count on that.
The lesson from Vietnam seems clear. The world can't afford to ignore the link between transitioning economies and emerging diseases. Because if it isn't H5N1, another virus will surely seize the opportunity.