Re: H5N1 genotype D1.1

https://www.cidrap.umn.edu/avian-influenza-bird-flu/cdc-h5n1-mutations-severely-ill-patient-could-boost-spread-risk-remains
 
There has been a second severe case of H5N1 infection involving the D1.1
genotype thousands of miles from each other.  In British Columbia a
teenager was in critical condition with an H5N1 D1.1 infection.  The
virus had two mutations that made it more infective in humans and it was
a respiratory infection in that case.  The claim was that the two
mutations occurred in the infected individual and the mutant took over
to cause the severe infection.
 
Another H5N1 D1.1 infection has occurred in Louisiana, and that patient
also has mutations that account for the severity of the infection, that
are not found among local wild birds, and they claim that they likely
occurred within that individual.  Two such cases likely means that there
is either a human adapted variant already existing, or that these
mutations commonly occur, and the genotype D1.1 may already be a
respiratory infection, so the two mutations would already be replicating
in the tissue that they would better adapt the virus to infect.
 
The Dairy virus is genotype B3.13.  Half it's genome comes from two
other strains of influenza (one high path and one low path).  D1.1 is
also a reassorted virus, but I can't find where the genotype is defined.
 Both virus still retain the H5 and N1 genes of the Asian avian
influenza virus that had 50% mortality in infected humans, but some of
their genomes come from other virus strains.  The dairy virus human
infections are mostly limited to eye infections, so the virus may not be
replicating in respiratory tissue. B3.13 is only one mutation away from
becoming more infective in humans, but somehow that mutation hasn't yet
occurred in any infected human.  It may be that the mutation would not
have an advantage replicating in mammary glands and tear ducts.
 
The D1.1 genotype is likely replicating in tissue where the mutations
would be selected for and would take over the infection of the host.
 
The CDC is currently not differentiating the dairy infection from the
D1.1 infections, but they should track them separately.  Both D1.1
infected individuals are seriously ill, but the B3.13 infected
individuals only have mild symptoms, mostly eye irritation.
 
https://www.cdc.gov/bird-flu/situation-summary/index.html