Evolution of flu strains points to higher risk of pandemic: study

0 Comments | AFP, May, 2008

CHICAGO (AFP) — Some strains of bird flu are coming ever closer to developing the traits they need to cause a human pandemic, a study released Monday said.

Researchers who analysed samples of recent avian flu viruses found that a few H7 strains of the virus that have caused minor, untransmissible infections in people in North America between 2002 and 2004 have increased their affinity for the sugars found on human tracheal cells.

Subsequent tests in ferrets suggested that these viral strains were not readily transmissible.

But one strain of the H7N2 virus, a low pathogenic avian flu strain isolated from a man in New York in 2003, replicated in the ferret's respiratory tract and was passed between infected and uninfected ferrets suggesting it could be...