In the last update a timeline was discussed but the source of the infection was unknown. The teen was in critical condition and had been H5N1 confirmed. The source was expected to linked to wild birds, and the prevalent genotype in wild birds was D1.1.
The full sequence from the teen was uploaded to GISAID
A/British_Columbia/PHL-2032/2024
The sequence was clearly D1.1
There were mixed signals at three positions.
Two were in the receptor binding domain (RBD) of H5,
E190D and Q226H (H3 numbering)
The third was in PB2, E627K, a well known mammalian temperature sensitive adaptation, which produce optimal polymerase activity at 41C for E, and 33C for K. The BCCDC (British Columbia Centre for Disease Control) acknoledged E627K, but was silent on the two RBD changes.
E190D (and PB2 E627K) were in the sequence from the 1918 pandemic
A/Brevig_Mission/1/1918
which was from Brevig Mission which was home to 80 adult mostly Inuit Natives. During the five-day period from November 15-20, 1918, 72 of the 80 adults died, including one who was well preservered in the permafrost and was the souce for the above sequence.
The two well studied RBD changes are Q226L and G228S
The BC teen has Q226H, which is VERY rare in H5
Today's Presser should discuss the necropsy of the teen's dog, who initially swabbed negative, but a necropsy allows analysis and testing of multiple internal organs, including lungs and brain.
The Presser should also cover additional possible sources of the teen's H5N1 infection as well as current condition.
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