Indonesian H5N1 Cluster Onset Dates Withheld
Recombinomics Commentary
May 19, 2006
a seventh family member, a 37-year-old woman. She developed symptoms on 27 April and died of respiratory disease on 4 May. No specimens were obtained before her burial, and the cause of her death cannot be confirmed. She is, however, considered the initial case in this family cluster.
The six confirmed cases in Sumatra include the woman's two sons, aged 15 and 17 years, who died respectively on 9 May and 12 May. The 28-year-old sister of the initial case died on 10 May. This sister had an 18-month-old girl, who died on 14 May. The fifth confirmed case, who is still alive, is the 25-year-old brother of the initial case. The sixth confirmed case is the 10-year-old nephew of the initial case. He died on 13 May.
the cases in this cluster are known to have participated in a family gathering around 29 April.
The above comments are from the WHO situation update on the large familial cluster in Karo, Indonesia. WHO typically publishes an update when cases are H5N1 confirmed by a WHO affiliated lab. The updates typically give the disease onset date, the hospitalization date, and the date of death.
The dates are important in determining the source of infections, especially when familial clusters are involved. A common source typically produces disease onset date that are within a few days of each other. Human-to-human transmission typically has a 5-10 day gap between the disease onset date of the index case, and the rest of the family members. In past familial clusters, the 5-10 day gap is common.
When there was a large cluster of cases in Turkey at the beginning of the year, WHO withheld the disease onset dates as well as the relationships between the clusters, which involved three sets of cousins. In one set three siblings were H5N1 confirmed and died and one additional sibling was hospitalized. In a second set of cousins, two family members were H5N1 confirmed and eight other family members were hospitalized.. In the third set, two were H5N1 confirmed and one of the two died. Disease onset dates were consistent with human-to-human transmission within the families and between the families. Disease onset dates from the first two sets was withheld, as was the relationship between the families.
WHO began provide the information in subsequent updates but has withheld disease onset dates in the current cluster. These disease onset dates clearly have the 5-10 day gap between the index case and the other family members. The onset dates were described in Indonesian reports as well as wire service reports, yet the dates have been withheld from the WHO update.
Similarly the sequences of human H5N1 isolates from Indonesia have also been withheld. The sequence from the index cluster identified in July, 2005 has been released, but all other human sequences are sequestered at a private WHO database. Most of the human Indonesian sequences in the private database have a novel cleavage site which is not found in bird H5N1 sequences from Indonesia These sequences should be released immediately.
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