WHO concludes H5N1 likely spread within family

Jun 22, 2006 (CIDRAP News) – The World Health Organization has concluded that Indonesia's recent family cluster of H5N1 avian influenza cases probably involved person-to-person transmission, including one three-person chain, according to the Associated Press (AP).

In a report obtained yesterday by the AP, the WHO said the first person in the cluster probably caught the virus from sick birds and then passed it to six family members, the AP reported. One of those family members, a boy, then probably infected his father.

But the WHO also said the virus has not mutated and did not spread to anyone outside the family, according to the AP story. The findings described by the AP match what the WHO had said previously about the cluster, but the agency has not released a final report on the episode.

Seven members of an extended family in North Sumatra province had confirmed H5N1 cases in May, and six of them died. Another family member, a 37-year-old woman, had a similar illness before the others but died and was buried without being tested for the disease. Her case is regarded as the index case in the cluster.

"Six confirmed H5N1 cases likely acquired [the] H5N1 virus through human-to-human transmission from the index case . . . during close prolonged contact with her during the late stages of her illness," the AP quoted the WHO report as saying.

Officials previously said several family members had slept in the same room with the index case-patient one night when she was coughing heavily.

The AP said the report was distributed at a closed meeting of avian flu experts in Jakarta. The meeting was organized after Indonesia asked for international help in dealing with avian flu.

One of the mysteries about the case cluster, the story notes, is why only blood relatives, not spouses, became infected. The AP says the WHO speculates that the family members had "a common genetic predisposition to infection with H5N1 virus with severe and fatal outcomes," but there is no evidence for that.

Keiji Fukuda, coordinator of the WHO's Global Influenza Program, told the AP the cluster seems to resemble other family clusters that involved limited human-to-human transmission after close contact.

"The really critical factor is, why did that cluster develop?" he said.

In other avian flu news, Malaysia today declared itself free of the disease after 3 months with no outbreaks, but said it would remain vigilant, according to an Agence France-Presse (AFP) report.

"Malaysia is now free of the H5N1 virus after 3 months since the last infection," Agriculture Minister Muhyiddin Yassin was quoted as saying at a news conference.

Malaysia had a rash of outbreaks starting in February in chickens in villages near Kuala Lumpur, the story said. Since then, five other outbreaks have occurred in poultry in the northern states of Perak and Penang.

Muhyiddin said the country must remain on alert because avian flu is still spreading in neighboring Indonesia. In new safety measures, he said slaughtering of chickens at "wet markets" must stop, and state governments have been asked to require farmers to breed birds in cages to keep them away from wild birds, the story said.

See also:

May 24, 2006, CIDRAP News story "Two generations of spread possible in Indonesia H5N1 cases"

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