Study Finds H5N1 Mutation Aids Infection in Cattle, Not Humans

New research shows that recent mutations in the H5N1 bird flu virus have made it easier for the virus to infect cattle, but there is no clear evidence of increased risk to humans.

Scientists report that some H5N1 strains can now attach to a sugar found in cattle, known as NeuGc, which is not present in humans or birds. This change allows the virus to grow more easily in the mammary glands of cows.

The study found that the mutations help the virus infect and multiply in cattle tissue, and may support its spread between cows. Researchers also say the change could increase the risk of transmission to other animals such as pigs, sheep, and horses, which produce the same sugar.

However, humans and birds produce a different sugar, called NeuAc. Laboratory tests show that while the virus can still attach to human cells, the new mutation does not improve its growth in human nasal tissue and may slightly reduce it.

KExperts say the virus has developed the ability to use both types of sugars, which could increase virus levels in infected cattle. This may lead to higher exposure for people who come into contact with infected animals.

Despite this, there is no indication that the mutation makes the virus spread more easily among humans.