Quotes of the Day

Sam Ngan isn't worried about bird flu. In a Phnom Penh market stall encrusted with chicken excrement, the 30-year-old Cambodian sells live birds shipped fresh each morning from farms that border Vietnamese provinces that have been struck hard by the disease. But Ngan is confident her merchandise is safe. Her chickens "are exposed to the sunlight and can eat from the earth," she explains, "so the disease does not affect them." Besides, she adds, "only foreign chickens are affected, not the local ones."

When it comes to bird flu, what you don't know can hurt you—and everyone else. Ngan is just one of many Cambodians clinging to reassuring misinformation about the disease. Cambodia recently became the third nation since 2004 to suffer a human fatality from bird flu, intensifying concerns that it will continue to spread. "The world is now in the gravest possible danger of a pandemic," warned Dr. Shigeru Omi, the Western Pacific regional director of the World Health Organization (WHO), during an international bird-flu conference last week in Ho Chi Minh City. "The longer the virus is circulating in animals, the greater the risk of more human cases—and consequently, the higher the risk of a pandemic emerging through genetic changes in the virus."

Such dire predictions about a disease that is so far believed to have killed just 42 people might seem hyperbolic, if not for the fact that it has already proven devastating among poultry. Since the virus known to scientists as H5N1 first emerged as a major concern in 1997, more than 140 million chickens and ducks across Asia have either died or been culled in a vain attempt to eradicate the disease. Bird infections lead directly to human infections—most recently a 21-year-old Vietnamese man who was confirmed with bird flu last Friday.

That's why international experts are now nervously scrutinizing the poultry flocks of Cambodia where birds and ducks are routinely raised in close proximity to human living quarters and sold live at unhygienic wet markets. In neighboring countries Thailand and Vietnam, such conditions led to the stubborn spread of bird flu, first among poultry, then in a handful of human beings. So far, Cambodia hasn't reported any major outbreaks, but Dr. Guan Yi, an avian-flu expert at the University of Hong Kong, fears it may already be entrenched there. "This virus is not just endemic in Vietnam and Thailand," he says. "In countries like Cambodia they don't have a systematic surveillance program, so we don't know yet. But I'm sure the virus is endemic in Southeast Asia."

The battle against bird flu hinges on information, cooperation and quick response—if the disease is spreading under the radar in Cambodia, it could wreck regional control efforts. With the help of the WHO, Cambodian officials have begun to slowly step up surveillance and education programs. But to contain the disease, Cambodia and its neighbors would need to radically modernize their animal husbandry practices, separating species (ducks are able to spread the virus without showing symptoms), keeping birds in pens and properly vaccinating flocks. The trouble is, such measures would require hundreds of millions of dollars to educate and equip poor farmers—money that developing countries clearly can ill afford. Officials at the U.N. Food and Agriculture Organization (FAO), which co-sponsored the Ho Chi Minh City conference, have appealed for international help with little success; wealthy donor nations contributed only $18 million of the $100 million needed last year to combat avian flu in Asia. "Given the size of the problem, that's just glaringly insufficient," says Dr. Samuel Jutzi, director of the FAO's animal production and health division.

The virus does not yet transmit easily from person to person, but recent research suggests that human infections may be more common than previously believed. The Feb. 17 issue of the New England Journal of Medicine reported that one person in Vietnam thought to have died of encephalitis last spring was actually infected with bird flu. The case was misdiagnosed because the patient did not show the respiratory symptoms typical of avian flu. Instead, the virus attacked the brain and the patient fell into a coma before dying. "We must have been missing cases," says Dr. Jeremy Farrar, one of the co-authors of the paper. "That's going to complicate disease surveillance."

The developed world is gradually gearing up to handle a potential crisis. The U.S. has just begun clinical tests on an experimental human vaccine for bird flu, and has made plans to stockpile 4 million doses. But if bird flu evolves into a pandemic, there's no guarantee this vaccine would stop a new strain. Despite that threat, a wide perception persists that the disease remains only a distant worry. That complacency is both understandable and dangerous. "A problem in a remote part of the world becomes a world problem overnight," Dr. Julie Gerberding, the director of the U.S. Centers for Disease Control and Prevention, told reporters last week. If so, the blind faith of a Cambodian chicken seller in the preventative powers of sunlight and local earth should be ample cause for international concern.

• Bryan Walsh
• Why the rest of the world should worry about outbreaks of the deadly virus in Cambodia