快猫短视频

PET birds may be harbouring avian flu viruses closely related to the strain
that killed six people in Hong Kong in 1997 and raised the spectre of a
worldwide pandemic.

Masaji Mase at the National Institute of Animal Health in Tsukuba, Japan, and
his colleagues found influenza A viruses in Indian ring-necked parakeets that
died after being imported to Japan from Pakistan. The researchers found the
viruses could also infect chickens and mice, but didn鈥檛 make them sick. It鈥檚 the
first time such viruses have been found in pet birds, Mase says.

The viruses were of the H9N2 variety, a type of bird flu that infected two
people in Hong Kong in 1999 and five people in China last year. H9N2 causes only
mild symptoms in people and isn鈥檛 a threat in its existing form, says Terrence
Tumpey of the US Department of Agriculture in Athens, Georgia.

However, the virus is very closely related to a much more lethal strain,
H5N1. This strain normally infects chickens. But in Hong Kong in the summer of
1997, it jumped directly to humans, infecting 18 people and killing 6, including
a three-year-old boy. The outbreak prompted the mass slaughter of millions
of chickens in Hong Kong鈥檚 open-air markets to contain the virus.

Tumpey warns that the H9N2 virus could cause a serious outbreak in humans if
it mutates or mixes with more virulent influenza A strains such as H5N1. Mase
and his colleagues are calling for countries that trade in pet birds to adopt
quarantine and surveillance procedures. 鈥淚 think that quarantine is most
important,鈥� Mase says.

There have been three great flu pandemics in recent history. In 1918, Spanish
flu swept the globe, killing 40 million people before disappearing as
mysteriously as it arrived. Its origins remain unclear. Avian flu strains caused
two smaller pandemics in 1957 and 1968, which each killed over a million people.
Most experts agree that another pandemic could strike at any time
(快猫短视频, 29 January 2000, p 16).
The question is not if, but when.