The H5N1 strain of bird flu swept through 10 Asian countries early this year, resulting in the death or slaughter of over 100 million chickens and the deaths of more than 20 people.
Since mid-December 2003, Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand and Vietnam have reported outbreaks of the avian influenza strain H5N1. Vietnam and Thailand have reported influenza H5N1 infection in humans with 32 laboratory-confirmed cases and 22 deaths, a mortality rate of nearly 70 percent. More than 100 million domestic poultry have been killed to halt the epidemic and prevent transmission to humans.
Now the United Nations health agency is investigating reports that bird flu, which experts say could mutate into a potentially deadly human pandemic under certain conditions, has now jumped the species barrier to infect cats.
This follows recent WHO reports that pigs can be infected with both avian and human influenza A viruses. Human influenza H3N2 viruses have been detected in pigs in Asia, Europe and Africa.
This is an extraordinary finding because it was thought cats could not be infected with highly pathogenic avian influenza (H5N1), the strain that has already killed some two dozen people in Asia this year and resulted in the deaths or culling of more than 100 million birds, World Health Organization (WHO) official Dick Thompson told a news briefing in Geneva today.
To date, H5N1 is the only strain of the H5 subtype known to jump directly from infected poultry to cause illness in humans.