Another H5N1 Bird Flu Fatality in Tangerang Indonesia
Recombinomics Commentary
August 8, 2006
INDONESIA said today that two teenagers had been confirmed as its 43rd and 44th bird flu deaths, making the country the world's hardest hit by human fatalities from the deadly virus.
"Samples from both of them have been confirmed as positive by both a health ministry laboratory and by the US NAMRU (Naval Medical Research Unit) laboratory," Runizar Ruzin, from the health ministry's bird flu centre, said.
A 16-year-old boy died last night and a 16-year-old girl died today, Rizin said.
The above comments chronicle the steady rise in the number of H5N1 bird flu fatalities in the Jakarta area. The 43rd death was in the Bekasi area, which has had reported cases since last year. The 44th cases is in the same area as the first reported case, in July, 2005.
The steady increase is cause for concern because the source of these infections has not been determined. H5N1 from the cases in the Jakarta area have a novel cleavage site and do not match the public avian sequences from Indonesia. The cleavage site has not been reported for any isolate, and the HA has additional unique sequences. Moreover, the recent release of the sequence data from these cases show that all eight gene segments have unique polymorphisms and phylogenetic trees of each gene indicate the human sequences form a separate branch that does not include avian isolates.
Since the reported avian isolates are from 2003-2005, it is possible that the lack of a match is related to the date of collection. However, two of the CDC avian isolates were from the fall of 2005 and those sequences did not match. Moreover, several recent human isolates have PB2 E627K and these isolates are evolving away from the 2005 human isolates. The more recent 2006 isolates are less related to the existing avian sequences. Many of the new polymorphism are frequently detected in mammalian isolates, raising the possibility of a a mammalian reservoir. Moreover, the recent isolates from the Karo cluster have acquired Qinghai sequences and an avian isolate from Bali has a Qinghai cleavage site.
Thus, the human H5N1 in Indonesia represents at least two distinct strains and the isolates from Java do not match the avian sequences.
Information on the recent avian samples sent to Australia for sequencing would be useful as would a more robust surveillance of H5N1 in migratory birds and mammals including swine, cats, and dogs. Moreover, testing of human cases with bird flu symptoms in the absence of contact with dead or dying birds would be useful.
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