Mutated Avian Flu Can Infect Humans

Previously reported on here

[Out of Japan]
2010/09/02
BY YURI OIWA THE ASAHI SHIMBUN
A strain of highly pathogenic avian influenza (H5N1) that mutated in pigs in Indonesia has acquired the ability to infect humans, researchers have found.

The discovery was made by a team led by virologist Yoshihiro Kawaoka of the University of Tokyo's Institute of Medical Science.

"There are concerns that a highly pathogenic flu virus which can easily be transmitted to humans could spread without being noticed," Kawaoka said. "Pigs must be tested for viruses even if they don't show symptoms."

Kawaoka and other Japanese researchers, in cooperation with Indonesia's Airlangga University, examined nasal, fecal and serum samples from 702 randomly chosen pigs in 14 provinces from 2005 to 2009.

Of pigs examined from 2005 to 2007, 7.4 percent yielded avian flu strains, which further studies showed were from an outbreak among poultry in the neighborhood.

Among 39 virus samples analyzed, one was found to have the ability to attach itself to human nasal or throat cells.

In the 2008-2009 survey, pigs showed traces of past infections, but no viruses were isolated.

Avian influenza usually does not infect humans. But because pigs are susceptible to both avian and human flu, the flu strain in question is believed to have mutated in an infected pig.

"Our data suggests that pigs are at risk of infection during outbreaks of influenza virus A (H5N1) and can serve as intermediate hosts in which this avian virus can adapt to mammals," the team said in a report published in the online edition of the journal "Emerging Infectious Diseases" of the U.S. Centers for Disease Control and Prevention.