The dreaded avian H5N1 influenza virus, also known as the chicken flu, is set to become the next global pandemic and is an area of intense study in the scientific community. As with previous influenza outbreaks on this scale, adaptive mutations or incorporations into circulating human influenza viruses may give rise to viruses with novel surface presented antigens [link] capable of infecting and transferring between humans with great efficiency.
So with the virus first isolated in 1996 [link], why aren’t we all down with the flu? It turns out that avian H5N1 carries a gene, hemagglutinin, specific to the sialic acid linkage to galactose common to the avian receptor, rather than the variant of humans. If this gene is required to confer transmission in species, could other genes also have an effect?
Recently, a team at the National Center for Immunization and Respiratory Diseases [link] had a bit of a gander and identified a few avian and human virus genes with a markedly high amount of compatibility. One in particular, avian PB1 gene, conferred the ability to form transcriptionally active heterotrimers and increased virulence, which they postulated would be crucial to outcompete seasonal viruses early in the pandemic. Keeping in mind the ability of the virus to evolve and adapt to become increasingly virulent for humans, the need for surveillance programs to clip the wings of the inevitable and delay its spread is highlighted.
Thomas Yen-Thon Teoh (40595940)
Primary Source
Genetic Compatibility and Virulence of Reassortants Derived from Contemporary Avian H5N1 and Human H3N2 Influenza A Viruses [link]
Secondary Sources
H5N1 avian influenza: timeline of major events [link]
Antigenic shift [link]
(picture) Bird Flu [link]
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