H5N1 Mutations Detected in Canadian Case Favor Human Transmission

In this recent MedCram video, Dr. Seheult delves into the critical topic of H5N1 influenza virus mutations, particularly focusing on a recent Canadian case where mutations have made the virus more favorable for human transmission. 

It is important to understand some of the nomenclature for influenza. On an influenza virus particle there are receptors, specifically something called the hemagglutinin (HA) and neuraminidase (NA) receptors. These are known by the “h” and “n”. These are the things that will bind to the receptors and allow the virus to get into a cell. The HA actually binds something called sialic acids. These are 9 carbon sugars that are found on the very tips of cells. These are important when determining if a virus is going to infect a certain species. In humans there is a sialic acid that is an α 2,6-galactose versus in birds it is an α 2,3-galactose.  From the HA on the influenza virus, it can bind to either of these sialic acids.

In 2007 a paper was done that discussed that most H5N1 viruses do not bind the sialic acid α 2,6-galactose receptor with as high an affinity and it is believed that this receptor binding property is the major factor preventing the H5N1 virus from efficiently transmitting from person to person and causing a pandemic. However, it was noted that the receptor binding preference of H5N1 viruses can be altered by only a few amino acid substitutions in the HA protein which could lead to a catastrophic pandemic. 

Recently the CDC for British Columbia and Public Health Agency of Canada released the genetics on the H5N1 strain for the patient that is hospitalized in Canada with the H5N1 infection. The press release shows that the genetic sequencing suggests that the H5N1 virus is closely related to those circulating in British Columbia poultry and belongs to the 2.3.4.4b clade and to the D.1.1 genotype which has been seen in the Western Canada and some western US states in poultry outbreaks. This was felt related to the spread of the virus from birds migrating south along the Pacific flyway. This is not the same genotype that has been seen in US dairy cattle.  

At the present time there is still much that is unknown and as time goes on we will see what happens and if there is development of any potential mutations that could lead to increase transmission of this virus in humans.

It is important again to concentrate on factors that are within your control such as working to ensure that your immune system is as good as it can be by ensuring you eat healthy, minimize processed foods, exercise, have good sleep hygiene, and get outside for sunlight. 

 

LINKS / REFERENCES:

Influenza virus and SARS-CoV-2: pathogenesis and host responses in the respiratory tract (Nature Reviews Microbiology) | https://www.nature.com/articles/s4157…

An Avian Influenza H5N1 Virus That Binds to a Human-Type Receptor (Journal of Virology) | https://pmc.ncbi.nlm.nih.gov/articles…

Sialic Acid Receptors: The Key to Solving the Enigma of Zoonotic Virus Spillover (Viruses) | https://www.researchgate.net/publicat…

Effects of mutations on a2,6 sialic-acid usage (DMS) | https://dms-vep.org/Flu_H5_American-W…

Canada’s national lab confirms H5N1 in hospitalized teen (Cidrap) | https://www.cidrap.umn.edu/avian-infl…

James Weiland (X.com) | https://x.com/JPWeiland/status/185783…

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