A teenager was admitted to the BC. Children’s Hospital on November 8th with a severe respiratory infection resulting in intensive care. Evaluation of the virus denotes changes in genes coding for the hemagglutinin protein that favor attachment to alpha 2-6 sialic receptors in the upper respiratory tract. H5N1 virus circulating in poultry attaches to alpha 2-3 receptors predominant in avian species but enigmatically also in the conjunctival tissue of humans. This is the reason why those involved in depopulation of flocks infected with avian influenza and workers in infected dairy herds develop conjunctivitis and only infrequently display upper respiratory involvement.
The two mutations that are evident from whole genome sequencing of the isolate from the patient are consistent with the clinical condition. It is not known whether these mutations occurred prior to infection or during the current clinical phase. Despite comments by Dr. Scott Hensley of the University of Pennsylvania, Perelman School of Medicine, following a review of sequence data released by the Public Health Agency of Canada, it is unlikely that the virus is of immediate pandemic concern to humans. It is generally accepted that monitoring of isolates from humans and ongoing surveillance will be necessary to detect potential changes in pathogenicity based on the presence of mutations.
Following investigations, health authorities in British Columbia have confirmed that there was no transmission from the patient to contacts within the ten-day period following hospitalization confirming that the virus was not contagious.
It is unknown how the patient was infected since there has been no release concerning residence, occupation or possible contact with free-living birds, animals or commercial poultry.