Mutations found in first severe case of human bird flu in US: Here's what it means

In a new development, it has been found that the first severe case of bird flu in the US involves mutations not seen in samples from an infected backyard flock on the patient's property, informed US Centers for Disease Control and Prevention. The analysis of the patient's sample from Louisiana - aged 65 and suffering from severe respiratory illness - showed mutations in the hemagglutinin (HA) gene, the part of the virus that plays an important role in it attaching to host cells, said CDC. One of the mutations was also noticed in a bird flu virus sample taken from a teenager in British Columbia who was in critical condition in a Vancouver hospital.

However, the health agency has affirmed that the risk to the general public remains low.

More about the mutations

The mutations in question are believed to make it easier for the H5N1 to bind to cell receptors found in the upper respiratory tracts of people. The bird flu virus otherwise attaches to a cell receptor that is rare in human upper airways and this is why H5N1 is not able to infect people easily and doesn't spread from person-to-person.

The Louisiana patient was infected with the D1.1 genotype of the virus recently detected in wild birds and poultry in the US, and not the B3.13 genotype detected in dairy cows, human cases and some poultry in multiple states.

The mutations seen in the patient are rare but not unseen, and are usually seen during severe infections. One of the mutations was also seen in another severe case from British Columbia, Canada. CDC assures that no transmission from the patient has happened to other people.

Will the mutations make bird flu more infectious?

According to STAT News, the mutations seen in the patient’s samples were not present in the virus from the birds, which means the mutations developed during the course of the person’s infection.

Scott Hensley, a professor of microbiology at the University of Pennsylvania’s Perelman School of Medicine told STAT News that it would have been more concerning if the mutations had been seen in the virus from the birds, because it would have suggested viruses in nature were acquiring these changes.

“More [genetic] sequences from humans is a trend we need to reverse — we need fewer humans infected, period,” said Angela Rasmussen, a virologist who specializes in emerging infectious diseases on X (formerly Twitter).

“We don’t know what combination of mutations would lead to a pandemic H5N1 virus and there’s only so much we can predict from these sequence data. But the more humans are infected, the more chances a pandemic virus will emerge.”

(Picture courtesy: iStock)