The new virus, called Fujian-like (FL), appears to be responsible for the increased occurrence of H5N1 poultry infections since October 2005, as well as recent human cases in China, the researchers said. FL has now also been transmitted to Hong Kong, Laos, Malaysia, and Thailand, resulting in a new bird flu outbreak wave in Southeast Asia that has caused human infections as well, according to the Hong Kong/St. Jude team.
The investigators also warned that it is possible that this new H5N1 variant will spread further through Asia and into Europe, as it evolves to form other sublineages that vary from place to place. This evolution into different sublineages also occurred during the previous two waves of H5N1 transmission that occurred during the past several years, according to the investigators. A report on these findings appears in the November online edition of the Proceedings of the National Academy of Sciences (PNAS).
The findings are significant because experts believe that H5N1 is the most likely virus to trigger a human influenza pandemic (worldwide epidemic). Moreover, the increasing number of transmissions from birds to humans in the past year supports this opinion, said Robert G. Webster, Ph.D., a co-author of the PNAS paper. Webster is a member of the Infectious Diseases department and holder of the Rose Marie Thomas Chair at St. Jude.
Based on their study of vaccinated poultry the Hong Kong/St. Jude team suggested that the vaccination itself might have facilitated emergence of this new variant.
This emergence and rapid distribution of FL, despite the vaccination program that was started
Source:St. Jude Children's Research Hospital