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.
Puzzle. Indeed, much about H5N1 remains a mystery. Scientists have long been puzzled by the fact that the unusually virulent virus, which has killed millions of birds, rarely infects humans. Earlier this year, researchers discovered that H5N1 isn't equipped to infect humans' upper respiratory tract, as colds and the seasonal flu do. Rather, it infects cells deep in the lungs, making it harder to spread.
Still, infectious disease experts are spooked by the fact that the bug has defied all efforts to eradicate it. Rigorous culling of birds and sanitation measures have extinguished past outbreaks of bird flu. "This thing is not going away," says Donald Low, head of microbiology at Mount Sinai Hospital in Toronto, who led efforts to fight the SARS epidemic there in 2003. "This is unprecedented."
The discouraging news comes after a seeming run of good luck. No human cases of H5N1 have been reported in Europe, though the virus spread to birds there over the past six months. And Vietnam, which reported the most human bird flu cases last year, has had considerable success controlling the virus. Last year, it reported 61 cases of bird flu in humans and 19 deaths. This year, it has reported no new cases.
Then came Indonesia. So far this year, 22 people have died of bird flu there, almost half of the cases worldwide. Two of those people died last week in West Java, Indonesian officials reported. It appears there is no link between their deaths and the northern Sumatra cases. Infectious disease experts say the Indonesian government has been less vigilant than other countries in educating local health workers, culling infected poultry, and quickly isolating human cases. In the Sumatra cases, a man who fell ill after he nursed his son refused treatment and fled before he died, increasing the risk that others would be infected. Experts also say that the country's poultry vaccination program may actually help spread the disease because vaccinated birds could harbor the virus and not fall ill.
Vigilance. Scientists expect more such outbreaks. "The hope is that you can get in there and contain it and reduce the risk of letting this virus learn how to become more humanized," says Low. That, he says, is what happened with SARS. But that requires vigilance worldwide and a quick response to contain outbreaks, a daunting task. Late last week, the WHO's assembly voted to launch a global fast-reporting system immediately. But few countries can provide that level of surveillance. The woman who hosted the barbecue was dead and buried before anyone realized that bird flu was raging in the family, and local residents resisted efforts by federal officials to investigate.
All of this hand-wringing about whether or not it's a pandemic is a distraction, says Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. "We are woefully unprepared." The world lacks a pandemic flu vaccine, hospitals in the United States have enough oxygen to treat patients for only two or three days, and the global community hasn't figured out how people will get food, water, and medical supplies during a pandemic that could disrupt economies for months. A report from the University of Pittsburgh's Center for Biosecurity says it would cost the average hospital $1 million to gear up, not counting buying more ventilators and antiviral drugs. Says Osterholm: "We're nibbling at the edges of the things we need to do."
With Jill Canada
This story appears in the June 5, 2006 print edition of U.S. News & World Report.