( in September 2005 also suggests that t...)Control measures fail to stop spread of new H5N1 virus

Moreover, since November 2005, some of the 22 H5N1 human infections reported from 14 provinces in China were from infected residents of metropolitan areas such as Shangai, Wuhan and Guangzhou, which are remote from poultry farms.

"We don't know yet whether the people in those metropolitan areas were infected locally by contact with poultry or by contact with other humans," Webster said, "but we suspect from the studies they are being infected by contact with poultry."

The researchers found the virus in samples taken from infected chickens in 11 of the last 12 months of the present study, compared with only four months during 2004-05. This indicates an increase in the incidence of H5N1 infection in 2005-2006 compared with previous years, which suggests that H5N1 viruses have not been effectively contained.

The investigators also conducted genetic studies of 390 H5N1 viruses isolated from poultry in the current study (30 percent of the total found in southern China) and found that 68 percent were of the FL sublineage.

The emergence of FL-like viruses and their success in replacing other H5N1 variants in such a short time demonstrates how difficult it is to control H5N1 in China, Webster said.
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Source:St. Jude Children's Research Hospital