# 3011
A new paper appears in the current issue of Virology, and it details a study that examined genetic sublineages of H5N1 virus samples taken from chickens seized along the Vietnamese border during the first 5 months of 2008.
The abstract is freely available, but you have to pay to read the entire paper. I’ve reformatted the abstract for easier reading below.
Characterization of a highly pathogenic avian influenza H5N1 virus sublineage in poultry seized at ports of entry into Vietnam
Nguyen T, Davis CT, Stembridge W, et al. Characterization of a highly pathogenic avian influenza H5N1 virus sublineage in poultry seized at ports of entry into Vietnam. Virology 2009 (early online publication) [Abstract]
Abstract
Highly pathogenic avian influenza H5N1 virus was detected in poultry seized at two ports of entry located in Lang Son Province, Vietnam.
Sequence analysis of the hemagglutinin (HA) genes from five H5N1 virus isolates and ten PCR amplicons from chicken cloacal samples revealed their close phylogenetic relationship to clade 7 H5N1 HA genes.
However, these HA genes exhibited extensive genetic divergence at both the nucleotide and amino acid levels in comparison to previously described clade 7 viruses; e.g., A/chicken/Shanxi/2/2006.
In addition, hemagglutination inhibition tests revealed antigenic differences between these and previously isolated H5N1 viruses from Vietnam. These results indicate that viruses with clade 7 HA are evolving rapidly in poultry in Southeast Asia.
A tantalizing opening, even if the abstract is a bit short on specifics.
Luckily we have Robert Roos of CIDRAP News to flesh out the details of this study for us.
I’ve just posted the opening paragraphs. Follow the link to read his report in its entirety.
Surprising diversity found in H5N1 in Asian chickens
Robert Roos
News Editor
Apr 14, 2009 (CIDRAP News) – H5N1 influenza viruses found in chickens seized at Vietnam's border with China in 2008 show a surprising level of genetic diversity, suggesting that the viruses are evolving rapidly and raising questions about disease surveillance and the effectiveness of prepandemic H5N1 vaccines, according to a team of Vietnamese and US scientists.
The findings suggest that the subgroup of viruses identified in the study has been circulating in the region either undetected or unreported for a "considerable amount of time," the report says. The viruses are in clade 7, a group that has not been found in an outbreak since one in China's Shanxi province in 2006.
Also, given the degree of difference between these clade 7 viruses and those used to make human H5N1 vaccines, "it is unclear whether or not humoral antibodies elicited by current vaccine candidates will have cross-neutralization activity against the new viruses," says the report, published recently in Virology.
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