H5N1 Cluster in Medan Indonesia Grows
Recombinomics Commentary
May 22, 2006
Local tests on Monday confirmed that a sixth family member, a 32 year old man, been infected with bird flu, said Kandun.
"He is the father of one of the victims, " Kandun said.
The above confirmation extends the transmission chain in the H5N1 bird flu cluster hospitalized in Medan, Indonesia. The size of the cluster is again at eight. Six have died and H5N1 has been confirmed in all except the index case, who died prior to collection of samples. The latest positive may have extended the human-to-human transmission (H2H) to H2H2H2H because the 10 year old nephew was the last to develop symptoms suggest that infection represented H2H2H and now confirmation of the infection of the nephew's father would add one more link to the chain.
This would be the longest H5N1 transmission chain reported to date, and raise questions about the sequence of the H5N1. The dominant human sequence in the Jakarta area (ranging from Lampung to West Java, including Tangerang, Jakarta, and Bekasi) has a novel cleavage site RESRRKKR and represents a clade that is distinct from bird H5N1 sequences from Indonesia, although the sequence is closer to Indonesian H5N1 sequences than any other published H5N1 sequences. However,. at least one sequence has a wild type cleavage site, RERRRKKR, and is closely related to the bird sequences, indicating two distinct sequence are co-circulating in the Jakarta area.
If the Medan cluster has the wild type sequence, the number of human sequences that are closely related to the published bird sequences would increase dramatically. The co-circulation of two distinct sequences in Indonesia would be cause for concern, because immunization may require two distinct vaccines and teh two sequences can easily recombine to produce more genetic diversity..
Clearly the H5N1 sequences in the WHO private database should be released immediately, and animal sequences throughout Indonesia should be significantly expanded. Recently there have been several H5N1 positive patients in Jakarta in West Java and Surabaya in East Java in addition to the cluster in North Sumatra.
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