2006-05-25-WHO to Study Bird Flu Deaths in FamilyUnderstanding Avian Influenza
2006-05-25-WHO to Study Bird Flu Deaths in Family
A team of World Health Organization experts has been deployed to help investigate what is being termed a worrisome family cluster of human cases of avian influenza in northern Indonesia, organization officials said yesterday.
"The leading hypothesis" right now is that the disease spread among family members after extremely close contact with ill relatives, said Dr. Julie L. Gerberding, of the United States Centers for Disease Control and Prevention in Atlanta.
But International health officials emphasized that laboratory tests from the family did not suggest that the A(H5N1) bird flu virus had mutated in any way that would allow it to spread among humans more readily, which scientists have said could set off a devastating worldwide pandemic.
While the virus has killed hundreds of millions of birds in the past several years, it is poorly adapted to humans and has only infected 214 people, almost always those who had had close contact with sick birds.
"Certainly this is the largest cluster we have in humans, and that by itself it worrying," said Dick Thompson, a W.H.O. official who arrived in Indonesia yesterday to join the seven-member team. "There's a suggestion of human-to-human transmission, and that is worrying."
He said United Nations investigators would study the travels of the Indonesian family over the last month to see whether they had visited places like markets that had put them at risk, or whether they might have passed the disease on to others.
People deemed to have serious exposure would be given anti-flu medicines and perhaps placed in quarantine if ill, he said.
He said that it would probably take a while to decide whether human-to-human transmission had occurred, because that determination was largely made by process of elimination, and that the W.H.O. team would have to investigate "all the other alternatives."
Scientists have long acknowledged that human-to-human transmission through extremely close contact might be possible. In a very few cases health officials suspect that a person extremely ill with the disease may have passed it to a family member, like a mother and child who shared a bed. But that is different from the kind of spread through casual contact that would occur in an pandemic.
Recent research has demonstrated that one of the reasons avian influenza does not spread easily among humans is that it infects cells deep in the human lungs.
So for transmission to occur, there must be intense and prolonged exposure to someone with a deep cough, doctors suggest. Normal human influenza virus lives in the throat and nose, and so spreads readily from sneezes. No evidence suggests that the A(H5N1) avian influenza virus was poised to acquire that ability.
Some human transmission is suspected in the Indonesian cluster because the family members did not keep birds and were not from a village with a known avian influenza outbreak. But potential routes of exposure are numerous in rural areas of Southeast Asia, particularly in Indonesia, which has been struggling to control the disease.
At least some members of the stricken family sold produce at a market where birds are slaughtered, a health official said, and could have contracted the disease there.
One family member got sick, died and was buried without being tested. She is believed to have infected six relatives, all confirmed to have had bird flu. Five of them died. Before dying, one of the children infected his father, who died Monday.
No cases have been reported in the village outside of the family. Such cases would suggest that the disease had become more easily transmissible.
"There are no cases in health care workers or members of the community ? that is the good news," Dr. Gerberding said. She emphasized that even if human-to-human transmission had occurred in the family, it was most likely caused by "the kind of close contact family members have with loved ones" who are ill.
Juan Lubroth, a senior veterinarian at the United Nations Food and Agriculture Organization in Rome, said his group's investigation had found no "indication at all that animals are involved in this transmission." But he, too, cautioned that poorly regulated markets for live birds still functioned in Indonesia, and the investigation is continuing.
"It has been a difficult situation because of Indonesia's decentralized government system," Dr. Lubroth said. "There is a national strategy but it's too early to say how it's panning out."