MADISON, Wisc. – Researchers at the University of Wisconsin-Madison are saying the H5N1 avian flu virus has been slowly evolving so that it can more easily infect humans.
Dr. Yoshihiro Kawaoka, the lead scientist of the study, says his team has identified a change in a viral protein that now enables the virus to develop in the upper respiratory systems of humans. This may allow H5N1 to spread more easily, eventually leading to a possible pandemic outbreak like the 1918 Spanish flu, which killed at least 30 million people around the world.
Kawaoka says the viruses circulating now in Africa and Europe are the ones closest to becoming a human virus. He noted, however, that other currently undetermined changes need to happen to it before its effect can reach pandemic proportions.
Still, the researchers believe it is inevitable that H5N1 will evolve and become capable of causing a pandemic outbreak.
Of the more than 250 H5N1 human infections that have been reported so far, greater than 150 have been fatal. To date, efficient human-to-human transmission has not happened. Instead, infection has occurred as a result of victims being in close contact with infected birds.
