A World of Worry
Disease experts scramble to find out how bird flu infected an Indonesian family
The 37-year-old woman in Kubu Sembelang, a village in North Sumatra, felt sick, but she hosted the family barbecue anyway. Six days later, on May 4, she died. Within a few days, seven other relatives succumbed to the mysterious contagion, including two of her sons and a brother, all of whom slept in the same room as the woman the night of the party. By last week, six had died.
Those were the bare facts at hand last week, as disease detectives raced to Indonesia to investigate the largest and most frightening avian influenza outbreak yet. It is the first time that the deadly H5N1 virus is thought to have jumped from one person to a second, and then to a third, sparking fears that the bug had mutated into a form that spreads easily among humans. That's all it takes to touch off a flu pandemic that could kill millions.
Bird flu had faded from most people's worry list in recent weeks. The spread of the virus into birds in Europe and Africa over the winter hadn't caused human cases there, and Vietnam and Thailand, two hot spots last year, have reported no human deaths this year. When the Indonesian deaths hit the news, overseas markets twitched and bird flu became Topic A at the water cooler again. The jitters accelerated midweek when Romanian officials quarantined more than 14,000 people in Bucharest, closing businesses and blocking streets with fences after discovering chickens infected with bird flu. Officials backed off after residents complained that they were stranded with no food or other supplies, and international health officials said that quarantine was not justified.
By week's end, with no new cases, it looked as if the world had dodged the bullet--for now. "So far, it seems that the infections are limited to a single family," says Dick Thompson, a spokesman with the World Health Organization's team in Indonesia, "but we won't know their status for a couple of weeks." Investigators are monitoring 54 people who had contact with the victims; they have been asked to "self-quarantine" by staying home and avoiding contact. Of those, 39 are on Tamiflu, an antiviral drug effective against H5N1. The rest are pregnant women, breastfeeding mothers, and children.
The big fear is that a cluster of cases with increased human-to-human transmission signals that the virus has changed in ways that enhance its ability to spread among the human population. WHO officials say that doesn't appear to have happened. The organization reported last week that it found "no evidence of genetic reassortment with human or pig influenza viruses and no evidence of significant mutations."
Since 1997, millions of birds have been infected by H5N1, but there are just 218 known human cases. In most instances, relatives and healthcare workers close to those infected didn't get sick. But in a handful of earlier incidents, it did appear that relatives and caregivers were directly infected. Figuring that out is educated guesswork. Epidemiologists have to find out when people fell ill, extrapolate from that when they became infected, and then investigate to see if they were near infected people or poultry during that time. Because the Indonesian family wasn't around poultry, scientists think these cases provide the first clear evidence of H5N1 sweeping through a chain of people. But it's unclear how the first woman became infected or how the virus infects people. It might be spread through food, coughing, feces, infected surfaces, or a combination of those. There may also be a genetic susceptibility, since blood relations seem to be affected more than in-laws.
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