Evidence for Human Transmission of H5N1 in Indonesian Cluster
Recombinomics Commentary
May 17, 2006
According to the World Health Organisation and experts familiar with the case, the family -- which raised a small number of pigs and had chickens, ducks and geese in the neighbourhood -- held a barbecue on April 29 when they ate pork and chicken.
The first person to fall ill was a 37-year-old woman, and two of her sons, her brother, sister, niece and nephew later fell sick. Except for the woman's brother, everyone has since died.
The above comments provide additional evidence for human-to-human transmission of H5N1in the Medan cluster. Local media reports indicate the mother developed symptoms on April 27, two days prior to the gathering. The mother was locally hospitalized and died May 4. The other family members developed symptoms around the time of her death and were hospitalized May 5. The first fatality was May 9, flowed by deaths on May 10, 12, 13, 14. This bimodal distribution of disease onset dates is common for familial clusters, and supports a mechanism of human-to-human transmission.
The size of the cluster (7 or 8) and number of fatalities (6) are the largest reported to date in Indonesia and raise concerns that the H5N1 transmission to humans is becoming more efficient. A similar increase in Turkey was linked to a change in the receptor binding domain (S227N) and similar changes in Indonesia are cause for concern. The only human HA sequence from Indonesia has a new glycosylation site and a novel cleavage site, but the sequence is from a fatality from last July.
More human sequences, including the current cluster, would be useful and sequences sequestered by WHO should be released immediately.
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