Alan Sipress - The Fatal Strain

In the five years after the virus reemerged in mid-2003, it tallied nearly 390 confirmed human cases and 245 confirmed deaths. For each one of those fatalities, almost precisely one million birds either succumbed to the disease or were slaughtered to contain it. That tremendous disparity between human and avian deaths underscores where the action has been. The bulk of the battle has consisted of culling, vaccinating, testing, and protecting poultry with the soldiers drawn from the ranks of the agricultural and veterinary services. The spread of disease among animals has long been beyond the mandate of public health, receiving little of the attention that a menace of such magnitude deserves.

Yet if there is any possibility of postponing future human flu pandemics, whether born of H5N1 or another strain, it means reducing the circulation of these viruses in animals. The less the microbe spreads and replicates, the fewer times the dice are rolled. And the less often the dice are rolled, the longer it will likely take for the virus to mutate or reassort into an epidemic strain.

By contrast, once a pandemic strain emerges and begins passing easily from one person to another, the only hope will be to retard its ineluctable progress by using antiviral drugs, quarantines, and other measures to keep people from mixing. A delay of even a few days would be no mean achievement. This could provide more time to start producing and distributing vaccines. Though they wouldn’t come soon enough for those infected at the beginning of the pandemic, millions of lives could be spared if vaccines arrive in time for those sickened toward the tail end. Yet ultimately, this is a rear-guard action. “You accept a victory as slowing the virus down,” offered Michael Ryan, WHO’s head of epidemic alert and response.

For much of their history, the fields of human and animal health have been divorced and introspective. When bird flu outbreaks were reported across Southeast Asia in early 2004, relations were strained between WHO and its sister agency, the FAO. Though officials on the ground tried at times to craft ad hoc alliances, tensions simmered over turf and money. Since then, these two UN agencies and the independent World Organization for Animal Health have taken steps to enhance cooperation, convening joint strategy sessions and setting up a common early-warning system to share information about bird flu and other diseases. But for many in public health, the fight in the animal kingdom has remained an afterthought.

“I don’t think the medical community has paid enough attention to the veterinary community in terms of the risks for humans,” said veteran scientist Dr. Michael Perdue. “It is the responsibility for human health, for the medical community, to reach out.” Perdue told me that means, for instance, pressing to get money for cash-strapped veterinary counterparts and helping set up more labs for testing animal diseases.

In 2006 Perdue joined the U.S. Department of Health and Human Services, where he took a leading role in preparing the United States for the coming epidemic. By the end of 2008, the department had spent about $1 billion toward creating a stockpile of antiviral drugs sufficient to treat about a quarter of the U.S. population. Another $1.5 billion went toward the development of advanced technologies for making pandemic vaccines, while nearly $1 billion more was invested in setting up a stockpile of prepandemic vaccines, which are based on current H5N1 subtypes and might afford limited protection to medical staff and other vital personnel in the early days of an epidemic. These measures, too, could save millions of lives, though they are powerless to preclude the inevitable.

Perdue, a genial Mississippi native, has a rare perspective on flu. He has hunted it on both sides of the species divide. As a microbiologist, he long probed the mysteries of avian influenza at the U.S. Department of Agriculture’s elite poultry research lab in Athens, Georgia. Once the disease launched its unprecedented attack on Southeast Asia, WHO called for reinforcements, and Perdue crossed to the human health side, signing on to the agency’s global influenza program in Geneva. From there, he was repeatedly dispatched to investigate human outbreaks. WHO is in a bind, he told me. As long as the virus remains primarily an animal disease, the agency must often defer to agriculture officials, who have priorities beyond fighting infectious disease—for instance, promoting livestock development. “It’s sort of animal health versus human health. It’s challenging,” Perdue said. “The problem is, once it becomes a human virus and WHO is clearly engaged, then maybe it is too late, because then it’s off and running.”

The trail of the fatal strain led me from one end of Southeast Asia to the other. I tracked the virus across nine countries, through hospitals and laboratories, into chicken coops, rice paddies, wet markets, and cockfighting rings. Yet few places were as remote and none as awesome as the floodplain of the Tonle Sap.

For much of the year, this lake in northwestern Cambodia is modest, covering slightly more than a thousand square miles at depths of about a yard. But each June, monsoon rains swell the Mekong River and its tributaries, forcing the water to back up into the lake and transforming it into the largest freshwater body in all of Southeast Asia. The lake’s waters overflow the banks and inundate another five thousand square miles, covering nearly a tenth of Cambodia’s area. Fields and forests are submerged. Then, with the coming of the dry season each October, the waters drain away.

Over the generations, Cambodians have adapted to the furious but predictable mood swings of their habitat. Many have built their homes on stilts to stay clear of the rising waters. Some inhabitants migrate with the shoreline, dismantling their dwellings as the water advances and reassembling them farther out. Others live on houseboats or floating homes of thatch, palm fronds, and clapboard mounted on bamboo rafts. This ecosystem has also made the shores of the lake and the surrounding floodplain a unique wintering ground for Asia’s wild birds.

It was the birds that brought me to the Tonle Sap. The monsoon was only weeks away, and soon they would migrate to summer breeding grounds in China, Japan, Siberian Russia, and even across the Bering Sea to North America. What if the birds were infected? Would the virus follow the multitude of flyways that radiate out from the Tonle Sap?

Few outside of Cambodia had heard of this wilderness. Yet here, in utter silence but for the occasional ruffle of wings, with no other sign of human life on this vast, flat expanse, I wondered whether a plague could be taking shape. If so, no place on Earth would be left untouched.

I came to the Tonle Sap floodplain looking for the virus. I found an insight. I realized we’re all living on a floodplain.

Several times each century, a novel flu strain emerges, often from the fountainhead of Southeast Asia. Death and disorder wash across the face of the planet. Sometimes they just skim the surface; other times they deluge all that lies before them. Then they recede. This cruel cycle isn’t as predictable as that of the Tonle Sap waters. But it is equally inevitable.

Those who live around the Tonle Sap have adapted with forethought and creativity to nature’s challenge. They have learned to ride out the flood. We have yet to do so.

For much of the last generation, the silence has been deceiving. Not since 1968 had a new flu virus menaced humanity and circled the world. But the outbreaks of avian flu that multiplied over the early years of this new century made it hard to continue mistaking luck for a change in the laws of nature. “The present situation is unique,” Margaret Chan has admonished from her bully pulpit in Geneva. “In the past, pandemics have always announced themselves with a sudden explosion of cases, and taken the world by surprise. For the first time in history, we have been given an advance warning.” She calls this an “unprecedented opportunity” for countries and communities to get ready.