WHO Probes Bird Flu Cluster
Friday, May 19, 2006
JAKARTA, Indonesia, May 18 -- An international team of health investigators arrived on the Indonesian island of Sumatra on Thursday to determine whether an unusually large cluster of human bird flu cases indicates that the highly lethal virus has mutated into a form easily spread among people.
Laboratory tests conducted for the World Health Organization confirmed this week that five members of one extended family in Kubu Sembilang village had died of bird flu during the first two weeks of May and a sixth had been infected but was recovering. A seventh family member, a 37-year-old woman who had been the first to fall ill, is also suspected of succumbing to the disease but was buried before samples could be taken.
The Sumatran cluster is the world's largest since the disease emerged in East Asia in 2003, although several dozen others have been reported. Any cluster raises the prospect that the virus has undergone genetic change allowing it to spread more readily among people, increasing the likelihood of a global pandemic.
WHO dispatched two investigators from its Jakarta office to northern Sumatra last week, but their initial efforts were stymied by distraught relatives' reluctance to discuss the cases. A second team, which arrived Thursday, included a senior epidemiologist from WHO's headquarters in Geneva and investigators from the Centers for Disease Control and Prevention in Atlanta and WHO's regional office in New Delhi.
"We are taking this very seriously," said Sari Setiogi, spokeswoman for WHO's Indonesia office. "The good news is that from our investigation to date, there's no evidence of further spread of the virus beyond the family."
Setiogi said that relatives, neighbors and health-care workers who treated the patients were being monitored and that none had shown influenza-like symptoms.
Influenza specialists have said they suspect human transmission played a role in several other clusters of infection, including instances in Thailand, Vietnam and elsewhere in Indonesia. But the disease has yet to demonstrate it can pass beyond the confines of a family, which would be necessary for bird flu to spark a global epidemic.
The source of the Sumatra outbreak remains unclear. Health officials said that they had heard a report of sick chickens near one of the victims' homes but that tests of poultry and other livestock in the village had failed to identify any infected animals. Agriculture Minister Anton Apriyantono said Thursday, however, that samples taken from chickens, ducks and pigs from the surrounding district had tested positive for exposure to bird flu.
Some Indonesian health officials have speculated that the afflicted family members, who lived near each other in four houses, had contracted the virus either by sharing a feast of infected chicken and pork or from contaminated manure. Health Minister Siti Fadilah Supari minimized the possibility that the virus had spread from one family member to another.
If they had all caught bird flu from the same contaminated source, the victims would have been expected to become sick within the normal incubation period for the disease, which at most is slightly more than one week. But the final victim, a toddler, became ill after that, raising the possibility that the virus was passed between relatives.
Nur Rasyid Lubis, who heads the bird flu prevention team at Adam Malik Hospital in North Sumatra, said five members of the family, including at least two children, were admitted at the same time on May 8 with fever and respiratory problems. X-rays showed symptoms of pneumonia. They all died over the following week.
Lubis reported that all seven victims from the family were related to one another by blood rather than through marriage, reinforcing the suspicions of some influenza specialists that genetic susceptibility could play a role in determining who catches bird flu.
The Sumatra cases and a separate fatal infection confirmed this week in Surabaya, Indonesia's second-largest city, increased the country's death toll from the disease to at least 30. Bird flu has infected more than 216 people worldwide, killing more than half.
Special correspondent Yayu Yuniar contributed to this report.