Scientists: Bird Flu Mutation Sets Stage for Flu Pandemic

The deadly bird flu virus has mutated and may infect people more easily if it begins spreading from human to human, according to a new study.

Scientist Dr. Yoshihiro Kawaoka, of the University of Wisconsin-Madison, said the H5N1 virus, commonly referred to as the bird flu, has mutated and can now develop in the upper respiratory systems of humans, which may increase the chances of the virus spreading from one person to another.

Recent virus samples taken from birds in Africa and Europe show mutations that resemble human viruses, Kawaoka stated in a report published in the Public Library of Science journal PLoS Pathogens.

Click here to read the report

The bird flu usually doesn’t develop in the nose or throat of humans, said Kawaoka, but this particular strain allows the virus to live in cooler temperatures similar to those found in the human upper respiratory tract.

In the new study, conducted in mice, researchers found a small, but significant change in the virus that allowed it to settle in the upper respiratory system, which may allow the virus to infect more cell types and spread more easily.

"The viruses that are in circulation now are much more mammalian-like than the ones circulating in 1997," said Kawaoka.

Bird flu strikes chickens and other birds and can infect humans who are in close contact with the infected animals. The new strain of the H5N1 virus may allow the disease to spread from one person to another through coughing or sneezing, according to the report. Temperatures in the lungs are also higher and more amenable to the efficient growth of the virus.

To date, there have been more than 250 human bird flu cases and more than 150 reported deaths. There have been no reported human-to-human transmissions.

Kawaoka believes that, as more humans and animals are exposed to the virus, the virus may continue to mutate and has the possibility of becoming a pandemic.