Bird flu mutations pose a growing threat to human health

The H5N1 (bird flu) virus is looming as a greater threat to humans. Scientists in British Columbia have identified a new mutation of the virus that could make it easier to infect people.

It was discovered in a teenage patient in critical condition in a hospital. How the teen became infected is unclear. Doctors don’t know if the mutation was in the infection the teen contracted. However, scientists speculate that it is more likely that the mutation occurred within the patient during their illness. If that is the case, the mutation of the virus would die out when the teen recovers.

Flu virologists say, however, that the mutations are a reminder that H5N1 is dangerous to humans, with the potential to trigger a pandemic if it develops a greater ability to infect people.

In a recent statement, Scott Hensley, Professor of Microbiology at the University of Pennsylvania Perelman School of Medicine, said that there is no indication of human-to-human spread, but that possibility is still feared. Hensley added that the new genetic sequence shows a modification in the virus’s ability to invade cells and that the situation calls for increased surveillance of the virus.

H5N1 binds to receptors on the human conjunctiva, the thin membranes covering the white of the eye and lining the inside of the eyelids. It produces mucous and tears to keep the eye moist. For the virus to spread easily in people, it would have to develop the ability to attach to a different type of receptor in the human airway – the receptors to which influenza A attaches. Two mutations spotted in the teen’s case are the type that makes the switch important to effective receptor attachment in the human airway.

The case in British Columbia is of high interest not only because the source of infection is unknown but also because the teen became critically ill. The virus, which has been circulating in North America, has only caused mild illness at this point.

There have been 53 confirmed cases of the disease in humans in the United States this year. All but one were in dairy farmworkers or people culling infected poultry. The patients had a mild illness, mostly conjunctivitis (pink eye), with mild respiratory symptoms. Thankfully, none required hospitalization.

British Columbia’s Provincial Health Officer, Bonnie Henry, notes the teen was admitted to the hospital on Nov. 8. Now, weeks after exposure, people who were in contact with the teen have not become ill.

The version of the virus that infected the teen is not the same version that is circulating in dairy cattle in the United States. The young patient was infected with a version found in wild birds. It has caused poultry outbreaks in British Columbia and Washington state. More than a dozen cases have been found in the last month.