Bird Flu Continues To Be Difficult to Spread
ATLANTA July 31, 2006 -
Scientists failed in multiple attempts to make a more contagious form of the H5N1 bird flu, suggesting the virus may have to undergo massive change to cause a human pandemic.
After genes from human and bird influenzas were mixed to mimic a natural process that could lead to a pandemic, the virus remained hard to spread, said researchers led by Taronna Maines of the Centers for Disease Control and Prevention. The study was conducted on ferrets, which flu affects much as it does people.
The H5N1 virus is known to have killed 134 people, most of them through contact with birds. Scientists believe the risk of a pandemic will increase as the virus spreads more widely, potentially infecting an animal or a human with H5N1 and a human flu strain at the same time.
Although the study suggests that H5N1 may not be close to becoming a pandemic virus, CDC Director Julie L. Gerberding said: "This does not mean that H5N1 can't develop into a pandemic strain. We are far from out of the woods."