Reassortment is the swapping of genes when two or more viruses infect the same animal.
The researchers say that their study of the genetic makeup of H5N1 subtypes collected since 1997 traces the evolution of the virus into a dangerous pathogen through a series of reassortment events. Results of the study indicate that domestic ducks in southern China played a key role in the generation of this virus. The H5N1 virus forced health authorities to slaughter millions of chickens in order to prevent the spread of the disease, which can quickly wipe out poultry in open-air markets and farms and spread to other flocks.
The investigators warn that outbreaks of H5N1 in East Asian poultry populations must be rapidly and effectively controlled to prevent H5N1 from evolving into a virus that causes a human pandemic, or worldwide epidemic. By cleaning up open-air markets and regularly slaughtering infected birds, Hong Kong remained free of H5N1 outbreaks in poultry during the 2004 influenza crisis, according to Robert Webster, Ph.D., member of Infectious Diseases department and holder of the Rose Marie Thomas Chair at St. Jude, and Richard Webby, Ph.D., also of the department of Infectious Diseases at St. Jude.
"In order to reduce the ability of H5N1 to trigger another poultry epidemic, officials in East Asia must follow Hong Kong's lead," Webster said. "Otherwise, H5N1 will likely continue to infect birds and other animals and eventually could evolve into a dangerous
Contact: Bonnie Cameron
St. Jude Children's Research Hospital