Friday, March 31, 2006
More Human Bird Flu In Azerbaijan
Russia's Itar-Tass news agency reported that a Baku laboratory had confirmed the presence of the H5 strain of bird flu in the girl. Her blood sample has now been sent to a WTO laboratory in Britain for further verification.This seems to be the family in which WHO had speculated that some of the cases were related to feathers plucked from dead wild birds. On one hand, there is nothing really different here. There has been a string of familial clusters in Indonesia and there was a big cluster in Turkey. It does make you wonder, though. Recombinomics commentary.
Velibeyov said the girl, of the Salyan region in southwestern Azerbaijan, was from a family which had lost three members to the H5N1 virus.
CurEvents FluClinic thread. Now it's two more cases, both sisters.
One of the Indonesian cases that really bothered me last year involved five cases. Two died before the first person was ever taken to the hospital (this was a poor farming village). Then there were two more after the first hospitalization. The reported intervals between first symptoms averaged to a week. There had been sick birds in the area, but those had been cleared more than a month before the last case.
On one hand, we are told that this virus is not good at infecting people, that you need significant exposure to get it, and that there are very few undetected cases out there. But the case of the two boys in Turkey who supposedly contracted H5N1 from playing with discarded gloves that had been used to cull birds seems to fly in the face of all that. They were never symptomatic and they should not have had massive exposure.
One possible explanation is that the virus is changing rapidly and that what may be true for a strain circulating in Cambodia is not for a strain circulating in Turkey. Another is that the virus may have a much longer latency period in some people.
So you get a small cluster as it spreads to one or two others who immediately die off, stopping the chain before it spreads any further.
My guess is, it's barely H2H-transmittable right now; you can catch it H2H, but it takes more than just casual exposure. (I remember Hansen's Disease; technically it's contaigous, but you have to really work at it.) And with the high lethality, you normally die off before others have had enough contact with you to catch it from you.
Also the clusters have been a consistent pattern in Indonesia.
It may be that casual transmission between humans doesn't occur once the virus has moved to deeper tissue sites and that the virus is contagious between humans for the very brief period when the virus is in the throat. If so, we are looking at a very long latency time indeed.
In the Indonesian cluster I mentioned earlier, the exposure to sick birds occurred at least two weeks prior to the first human illnesses.
One problem with detecting H5N1 cases is that traditional swab testing doesn't work well because there generally is not virus in the throat and mouth for very long.
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