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H7N9 ?Discussion
Firstly it is very early days and the fog of war is thick so much of the information currently available is likely to be updated.
What we do seem to know, based on the currently available data, is this is a Low Pathogenic Avian Influenza (LP AI) (see Genewurx?s analysis ) caused by a reassortment of two avian type A influenza viruses. H7N9 (which supplied the two surface proteins HA & NA and determine the antigenic response) and H9N2 (which supplied the 6 remaining RNA strands which code for all the internal proteins - see Guiseppe?s post)
At this point I would be very cautious about attributing high virulence to the virus based on ?3 cases 2 deaths? as serious illness, and deaths, lead to lab analysis of the causative agent so it is often the exceptional that get initial attention. Media reports say family contacts are now being followed and this should lead to a better understanding of the virus? human-to-human (H2H) transmission potential. Serological testing, more generally, will be needed to find out how many subclinical and Influenza Like Illness (ILI) cases there have been underlying the 3 confirmed cases. This post, written at the start of the 2009 H1N1, may help clear up some of the confusion likely to occur by the reported case numbers.
It may be helpful to review the HP/LP nature of flu at this point. H7 ? like H5 ? flus have the potential to come in both flavours. The LP form can, at any point, become HP by the addition of basic amino acids at the point of cleavage on the HA protein. This change allows a much wider range of proteases (a common type of protein that is supplied by the infected host which cuts other proteins in two). As the cleavage of HA at this point is required for the virus to infect the host?s cell this change allows infection more generally around the body not just in the lungs. The name HP comes from the effect this change has on poultry where the HP form is far more deadly but in humans this is not necessarily the case. 1918 H1N1 was not HP (no H1 are) the H5N1 which has caused deaths, in humans, is HP (but there are also LP forms circulating in birds). This link is to a paper by Ilaria Capua which has an excellent listing - in Table 1 - of all the know human zoonotic flu infections.
For Media reports see this thread
For more on the genetics see this one
Firstly it is very early days and the fog of war is thick so much of the information currently available is likely to be updated.
What we do seem to know, based on the currently available data, is this is a Low Pathogenic Avian Influenza (LP AI) (see Genewurx?s analysis ) caused by a reassortment of two avian type A influenza viruses. H7N9 (which supplied the two surface proteins HA & NA and determine the antigenic response) and H9N2 (which supplied the 6 remaining RNA strands which code for all the internal proteins - see Guiseppe?s post)
At this point I would be very cautious about attributing high virulence to the virus based on ?3 cases 2 deaths? as serious illness, and deaths, lead to lab analysis of the causative agent so it is often the exceptional that get initial attention. Media reports say family contacts are now being followed and this should lead to a better understanding of the virus? human-to-human (H2H) transmission potential. Serological testing, more generally, will be needed to find out how many subclinical and Influenza Like Illness (ILI) cases there have been underlying the 3 confirmed cases. This post, written at the start of the 2009 H1N1, may help clear up some of the confusion likely to occur by the reported case numbers.
It may be helpful to review the HP/LP nature of flu at this point. H7 ? like H5 ? flus have the potential to come in both flavours. The LP form can, at any point, become HP by the addition of basic amino acids at the point of cleavage on the HA protein. This change allows a much wider range of proteases (a common type of protein that is supplied by the infected host which cuts other proteins in two). As the cleavage of HA at this point is required for the virus to infect the host?s cell this change allows infection more generally around the body not just in the lungs. The name HP comes from the effect this change has on poultry where the HP form is far more deadly but in humans this is not necessarily the case. 1918 H1N1 was not HP (no H1 are) the H5N1 which has caused deaths, in humans, is HP (but there are also LP forms circulating in birds). This link is to a paper by Ilaria Capua which has an excellent listing - in Table 1 - of all the know human zoonotic flu infections.
For Media reports see this thread
For more on the genetics see this one
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