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Biotech / Medical : SARS and Avian Flu -- Ignore unavailable to you. Want to Upgrade?

To: Amy J who wrote (1384)	2/4/2004 5:33:23 AM
From: Henry Niman	Respond to of 4232

The flu (and SARS) virus mutates all the time. Some of the mutations become stable because they offer an advantage while others appear because they happen along with other mutations that offer some selective advantage. For flu, the database of sequences is quite large and although most sequences are from 1968, a few go back to outbreaks at the beginning of last century, including the 1918 pandemic. When I looked at the mutations in a partial sequence from one of the fatal Vietnamese cases, there was one mutation that was very new and I couldn't find it in any H5N1 isolates, except one from a chicken in Scotland in 1959. It was not in the sequence of the smuggled duck, which is very close to the Vietnamese sequence. This suggested that the change was fairly recent. I could find other isolates (H1N1, H6N1, H7N1, H9N1, H11N1, etc) that had the mutation and one was an H5N1 from 1918. discuss.agonist.org The names of the virus are informative. They give the type, species, location, isolate number, and date of isolation. If there is no species listed, it is a human case. Thus the isolate cited above, A/Bevig_Mission/1/1918(H1N1) means that it is influenza A, isolated from a human at Bevig_Mission. It was the first isolate at that location in 1918 and the virus was H5N1. If you look at the list for P340S (which means that the Proline,P, at amino acid position 340 in the neuraminidase protein mutated to Serine,S), you will see only one H5N1 isolate, A/chicken/Scotland/59(H5N1), which means it was an isolate from a chicken in Scotland in 1959 (they didn't give the isolate number). The isolate from the Vietnamese victim is A/Vietnam/1196/2004(H5N1) which means it was the 1196th isolate from a human in Vietnam in 2004. The smuggled duck is A/duck/China/E319-2/03(H5N1) - it was smuggle onto Quemoy Island in Dec, 2003.