Resistant H5N1 Fixed in Egypt Recombinomics Commentary
February 11, 2009
The National Veterinary Labs
(NLQP) in Egypt have released 20 HA sequences collected between January
8 and June 15, 2008 (see list here).
17 of these sequences mapped with the vaccine resistant sequences
isolated from vaccinated
flocks at the end of 2007
/ beginning of 2008. The isolates were found throughout Egypt
and were also in Israel
map). The high frequency in the above sequences, including
all sequences from isolates collected since April, indicate this
sub-clade has become fixed in Egypt and will likely be found in new
cases in Egypt.
Although the sequences have
the Egyptian markers from clade 2.2 isolates dating back to 2006, each
season a new series of polymorphisms is appended onto this
background. Some polymorphisms, such as G743A,
are appended onto multiple distinct backgrounds. Moreover, the
newly acquired polymorphisms link back to various H5N1 in circulation
acquisitions, including a 3
BP deletion from clade
7 sequences in Hunan, support evolution by homologous recombination
with significant applications for vaccine target selection.