7 6 月 2006 at 9:06 下午 #3345馬丁參加者
from Xinhua:引用：The Chinese government should review the strategies and effects of the
bird flu control efforts of the past two years and improve them to cope
with the epidemic which is still a serious threat, said a Chinese
scientist on Monday.
“When, and to what extent, the current avian influenza virus could
evolve into a human pandemic is unpredictable. We should do our best to
reduce the risk of a human pandemic influenza breaking out and make
necessary preparations before such a risk becomes reality,” said Chinese
bird flu control expert Liu Xiufan.
Liu, a member of the Chinese Academy of Engineering (CAE), said at a
national conference of the CAE members that controlling the H5N1 virus
in poultry at its source is the best way to reduce or even eliminate the
risk of a human pandemic virus.
He said the full range of control measures should include enforced
biosecurity of poultry farms and restriction on the movement of poultry
and products, culling of infected poultry, quarantine, disinfection, and
prudent use of vaccines.
Some changes in the H5N1 virus have taken place recently. The virus has
increased virulence to ducks, and the currently available vaccines are
not effective for protecting poultry, said Liu.
The H5N1 viruses isolated during the 2004-2006 period have increased
their ability to replicate in mammalian cell culture. The transmission
mode of the viruses is changing from fecal-oral to aerosol, said the
scientist, adding that the viruses have increased resistance to the
environment, especially to temperature.
He noted that it is a big challenge for China to eradicate the H5N1
viruses because the viruses have been circulating in poultry in China
for some time.
The outbreaks of bird flu have affected vast areas of China. The
extensive presence of waterfowls and vaccinated birds as the carriers of
the H5N1 virus has increased the difficulty of effective control and
eradication, Liu said.
China produces 3.7 billion waterfowls each year, more than 75 percent of
the world’s total.
Huge numbers of small poultry holders scattered all over China increase
the difficulty of disease prevention and control, Liu added.
Because bird flu infection has become endemic in some areas in China and
cannot be stamped out in a short time, the government should draw up a
short-term plan of prevention and control and a long-term program of
eradication, Liu added.
More than 80 outbreaks of bird flu have been reported in China since
February 2004, affecting 24 provinces, municipalities and autonomous
regions. 18 confirmed human cases with 12 fatalities have been reported
since last September.