BANGKOK, Thailand --Two strains of bird flu in Asia may combine to create a highly lethal and easily transmissible virus, a U.N. health official warned Wednesday, amid widespread fears that the disease could cause the next human pandemic.
The U.N. Food and Agriculture Organization on Tuesday confirmed that birds in North Korea were infected with the H7 bird flu strain that sickened nearly 90 people and killed one in the Netherlands two years ago. It is distinct from the H5N1 strain that has decimated poultry populations across Asia since December 2003 and killed at least 50 people in Vietnam, Thailand and Cambodia.
Both strains can jump from birds to humans but only the H7 virus has been shown to spread from person to person, raising concern that it could unite with the deadlier H5N1 strain and cause a global pandemic.
"The fact that two viruses -- one with a proven track record of transmitting easily into people and another with a mortality rate of between 50 and 80 percent -- are circulating in Asia at the same time is something to keep a very close eye on," William L. Aldis, the World Health Organization representative in Thailand, told The Associated Press.
If H7 and H5N1 came into contact and exchanged genetic material, it could create an "organism with H5 lethality and H7 transmissibility," said Aldis.
http://www.boston.com/news/world/asia/articles/2005/04/06/who_expert_bird_flu_strains_could_combine?mode=PF