On High Alert

When World Health Organization (WHO) parasitologist Carlo Urbani was treating the first cases of an unknown respiratory disease in the Hanoi-French Hospital in late February and March of 2003, he believed he might be facing the front end of an avian-flu epidemic. Dr. Olivier Cattin, the medical coordinator at the hospital, had alerted Urbani and told him the Chinese-American patient currently in the emergency ward suffering from high fever, severe muscular pains and labored breathing had possibly come down with the disease. Virologists in Hong Kong soon determined that the agent was a novel coronavirus, not a mutant flu. But Urbani, who would die of SARS on March 29, went to his grave suspecting the world was on the verge of another influenza pandemic.

Nearly a year later, his worst fear may be coming true. If a virus, as Nobel laureate Peter Medawar described it, "is a piece of bad news wrapped in a protein," the past few weeks have had all the bad news the world can handle as avian influenza has broken out in Korea, Japan, Taiwan and Vietnam. Already, the disease appears to have jumped the species barrier, killing at least four people, and the virus is suspected of causing another 10 deaths. Asia has stared down avian-flu outbreaks before, notably in Hong Kong in 1997 when the city's Agriculture, Fisheries and Conservation Department officials culled 1.4 million chickens, as well as ducks, geese and other birds, after 18 human cases resulted in six fatalities. This time around, however, the spread of the outbreak to several countries has public-health officials on high alert, wary of the potential for a pandemic.

In Vietnam, where already more than 1 million birds have died from the virus, and at least another 800,000 have been slaughtered as a precaution, Ministry of Agriculture and Rural Development (MARD) officials were reassuring the public as late as Jan. 7 that "there has been no sign the disease will affect human health" — even though 12 patients had already turned up at the National Institute of Pediatrics with an "unusual" virus, according to hospital director Dr. Nguyen Thanh Liem. Even more worrying, it now appears that there were mass chicken die-offs in Vinh Phuc province in northern Vietnam as early as last July, six months before the government officially acknowledged the emergence of avian flu. Giapfa Comfeed Vietnam Ltd., a poultry company in Vinh Phuc's Tam Duong district, told TIME that 20,000 of its chickens died with symptoms correlating with avian flu. The company says it sent blood samples to the MARD's Veterinary Department, whose tests revealed that the chickens had been killed by an unknown agent. Van Dang Ky, a veterinarian from the department's epidemiology unit, admits, "The first signs of an epidemic were found in Tam Duong district in July 2003. At the time, Vietnam was preparing actively for the 22nd Southeast Asian Games and we thought we could control the disease, so we did not announce it for political and economic reasons." Anton Rychener, a United Nations Food and Agriculture Organization representative in Vietnam, confirmed that ministry officials told him there had been previous outbreaks. (Ministry of Foreign Affairs officials have denied MARD's assertions.)

The appearance of avian flu in July, and the apparent Vietnamese cover-up, would mean that this virus has had months to roll through the chicken population, possibly mutating and becoming more pathogenic as it goes. The culprit this time is the same as in Hong Kong in 1997: the H5N1 influenza virus. Historically, this virus has wreaked havoc mainly on poultry. Among chickens, the disease manifests itself as a hemorrhagic fever, turning a pen of healthy birds into a bloody mass of goop and feathers within 24 hours. Since the 1960s, each reported appearance of the disease has drawn a rapid response from international health officials concerned more about the potential for human infection than the loss of a few feathered friends.

Their fear is that of all the diseases in the world today — from SARS to AIDS, anthrax to Ebola — the single microbe with the greatest potential to become, as epidemiologists say, a "slate wiper," is influenza. Previous pandemics, such as the global outbreak of 1918 that killed an estimated 60 million people, have precipitated some of the greatest die-offs in history. We've all had the flu, of course, but those few days off from work with the sniffles are a completely different illness from that caused by a novel influenza against which we have no immunity. Without antiviral medications or a vaccine, a new influenza strain could kill you in days.