2006年VOA标准英语-Scientists Develop Possible Bird Flu Vaccine Us（在线收听）

By Deborah Block
Washington, D.C.
26 June 2006
 
watch Bird Flu report

Researchers are working on developing vaccines for bird flu before it becomes a worldwide epidemic.  The University of Massachusetts Medical School in the United States has teamed with a British drug company to come up with a potential vaccine using bird flu DNA. 

---------

Bird Flu Virus   
  
Traditional flu vaccines use weakened flu viruses and take months to produce on a large scale.

The bird flu DNA vaccine could be easily duplicated and produced in large quantities.  DNA is a molecule found in a cell that contains a specific genetic blueprint.  The DNA-based vaccine would be inserted using a pressurized gun that penetrates the skin without using needles.  

So far, it appears the bird flu virus has spread only to people who handle poultry or have eaten contaminated meat.  It has killed more than 125 people worldwide, as well as large poultry flocks in Asia, Europe and Africa.  Experts fear millions of people could die in the future if the virus combines with human flu strains and produces a new strain that is highly contagious to people.

Dr. Shan Lu  
  
Dr. Shan Lu is with the University of Massachusetts Medical School. "Clearly the bird flu is spreading to more places. The question is when they will jump to humans.  That is the question we don't know, but we have to prepare."

Researchers are trying to figure out how the tiny organism replicates, so it can be stopped from spreading.  Waterfowl and other migratory birds can tolerate the organism, secreting it as waste into ponds, lakes and rivers.  But the virus becomes deadly to humans when it infects birds that live on land, particularly chickens.  Right now the only way to control bird flu is to slaughter diseased poultry.

 
Daniel Perez 
  
Daniel Perez is head of a bird flu research program at the University of Maryland.  He is unsure whether the vaccine, if proven effective, would stop a worldwide epidemic since bird flu viruses mutate, changing constantly. 

"The virus is completely unpredictable.  I think one of the biggest questions would be how many doses we have to make, how soon we have to have them, because if it [an epidemic] happens tomorrow, we don't have them," warns Mr. Perez.

The vaccine will be tested on animals soon. Human trials are expected in about six months.