March 13, 2006

 

One out of every hundred poultry in China may have bird flu
 

 

One out of every hundred chickens, ducks and geese in markets in southern China are carriers of the deadly H5N1 avian flu virus, researchers in Hong Kong and China have found.

 

Experts fear that these carries, who do not display symptoms of the disease, will make it harder to control the disease.

 

This is the first time researchers were able to find conclusive data on infected chickens who do not show signs of the disease. Chickens usually die within 24 hours of being infected.

 

Researchers collected 51,121 samples from birds in live-poultry markets across seven provinces in southern China from January 2004 to June 2005.

 

The H5N1 virus was found in 1.8 percent of ducks, 1.9 percent of geese, and 0.26 percent of chickens.

 

The birds look healthy but they can infect others and kill people, said microbiologist Guan Yi from the University of Hong Kong, who led the project.

 

In China, how people died from the disease remains a mystery as most of the fatal cases where people died from H5N1 had no reported H5N1 outbreaks or unusual deaths in birds.

 

Experts began questioning this week if apparently healthy but infected birds might be spreading the disease after a man died from visits to several poultry markets and an abattoir.

 

Guan is positive that infected ducks, geese and chickens shed the virus in their faeces into the environment and people caught the virus when they are exposed to it.

 

While China has pledged to vaccinate all its chickens, experts say that is impossible because not only does China have the world's biggest population of chickens; millions of them are also reared in the backyard.

 

Furthermore, the vaccines may not be entirely effective in controlling the virus. The H5N1 strain was once isolated in Guangdong in 1996 but it has now spread to various parts of China, other parts of Asia, Europe and the Middle East. Experts say the vaccines used in China can only keep birds alive, but it does not stop the virus from infecting other birds.

 

Chinese state secrecy and academic squabbles have hampered vital research material to scientists trying to develop a viable bird flu vaccine. Crucial research and live virus samples have been denied to international researchers as Chinese officials dislike the publication of independent findings and are trying to shut out any research that is not under government control.