New bird flu mutation could leave humans ‘vulnerable to infection’: experts

Bird flu is back with a vengeance.

Medical experts have discovered that one variant of the avian flu virus, dubbed H3N8, has undergone several mutations and can now cause more severe infections.

Additionally, the H3N8 virus — which is endemic among poultry farms throughout China — is transmissible by airborne droplets between animals that have no physical contact.

“Human populations, even when vaccinated … could be vulnerable to infection at epidemic or pandemic proportion,” researchers wrote in the journal Cell.

The H3N8 variant has been found in horses, dogs and seals as well as birds, but it has not made the leap into human populations — yet.

In March, however, a woman in China became the first known human fatality of H3N8 avian flu. She likely became infected in a “wet market,” an open-air market where live animals are bought and sold.

Such markets are considered by public health experts to be rich breeding grounds for cultivating potentially deadly viruses, bacteria and other infectious agents.

Last year, two boys were also infected with the H3N8 virus and survived. The new virus has a particular affinity for the cells in the human respiratory system.

“[A]n avian H3N8 virus isolated from a patient with severe pneumonia replicated efficiently in human bronchial and lung epithelial cells, was extremely harmful in its effects in laboratory mammalian hosts and could be passed on through respiratory droplets,” study co-author professor Kin-Chow Chang, of the University of Nottingham, said in a news release.

Avian flu viruses don’t usually infect people, but there have been rare cases of human infection with these viruses, according to the Centers for Disease Control and Prevention.

In humans, bird flu infections range from no symptoms or mild illness to severe disease that can cause death. Person-to-person infection is very rare, and there have not been any widespread infections among humans.

However, the CDC emphasizes, that avian flu viruses mutate and could gain the ability to spread easily between people. Therefore, monitoring for human infection and person-to-person spread is extremely important for public health.

“Acid resistance of influenza virus is … an important barrier for avian influenza virus to overcome to acquire the adaptability and transmissibility in new mammals or humans,” the study authors wrote, referring to the protections afforded by acids in the immune system.

“The current novel H3N8 virus has not acquired the acid resistance yet. So, we should pay attention to the change on acid resistance of the novel H3N8 virus,” Chang added.