Home>News Center>China
       
 

Bird flu requires tight watch
By Qin Chuan (China Daily)
Updated: 2004-04-05 07:49

Vaccines used in China to combat bird flu in chickens have so far proved effective with no new cases of the deadly virus reported in any of the nation's flocks, experts say.

Strong surveillance measures continue in China to prevent the disease from spreading again. A recent report of the United Kingdom-based New Scientist magazine warns that vaccinations can lead to the evolution of new bird flu strains, increasing the risk of human pandemics.

According to the report, vaccines, especially those for the flu ones, are never 100 per cent effective.

While such vaccines can prevent animals from falling ill, small amounts of virus can still replicate inside creatures' bodies and spread from animal to animal.

Such "silent epidemics," the report said, are very hard to spot, and can cause new outbreaks if unvaccinated animals are exposed or if vaccination programmes end too early.

"Such possibilities do exist if the quality of vaccines used are not good enough," Chen Hualan, chief of the national bird flu reference lab with the veterinary research institute in Harbin in Northeast China's Heilongjiang Province, admits.

But she said the inactivated vaccines used in China have proved so far to be effective. And surveillance measures have shown vaccinated chickens in China do not carry the bird flu virus.

"Vaccination does not mean everything is OK. We must never spare our vigilance," said Jia Youlin, chief veterinarian and spokesman for bird flu control at the Ministry of Agriculture.

According to Chen, surveillance measures include the testing of waste samples from vaccinated chickens to see whether there are any bird flu viruses present.

Chen said another more scientific way of putting unvaccinated "alarm" chickens among vaccinated chickens has been also adopted in the country.

The use of such chickens is also recommended in the New Scientist report.

Once bird flu viruses exist, the alarm chickens will show symptoms, Chen said.

The surveillance part of the equation is vital, said Ilaria Capua of the bird flu reference lab of the World Organization for Animal Health in Legnaro, Italy, according to the New Scientist report.

"The vaccine used without this monitoring can have a boomerang effect, and become a tool to spread the virus, not control it," the report quoted Capua as saying.

In 1995 Mexico stopped an outbreak of severe H5N2 flu by vaccinating chickens. But the virus was still circulating silently, and Mexico is still vaccinating, the report said.

Normally the bird flu virus changes little in chickens, because it rarely persists long enough, but in Mexico the virus has been exposed to vaccinated chickens for years. That encouraged new forms of the virus to evolve, the report quoted David Suarez of the US Department of Agriculture's poultry research lab in Georgia as saying.

China lifted its restrictions on the last two bird flu epidemic areas on March 16, but Jia, while announcing the news, said no efforts should be spared to prevent and control the disease.

 
  Today's Top News     Top China News
 

State of emergency law to set basic rights

 

   
 

HK: Calls for reason amid strife concerns

 

   
 

Bird flu requires tight watch

 

   
 

Iraqi anti-US protests turn violent, 30 killed

 

   
 

Corruption haunts Wenzhou high-rise project

 

   
 

Job hunt an uphill battle for female graduates

 

   
  HK: Calls for reason amid strife concerns
   
  Corruption haunts Wenzhou high-rise project
   
  Bird flu requires tight watch
   
  State of emergency law to set basic rights
   
  Gas explosion kills one, leaves 4 others missing
   
  60,000 protest Chen Shui-bian in Taipei
   
 
  Go to Another Section  
 
 
  Story Tools  
   
  Related Stories  
   
Ministry still on alert against Bird Flu
   
China declares victory in bird flu fight
   
Vaccines target bird flu virus
   
China works with WHO on SARS, bird flu vaccines
   
WHO works with China on SARS, bird flu vaccines
   
Canadian bird flu cases spreading
  News Talk  
  Sex Education, a necessary evil?  
Advertisement
         
主站蜘蛛池模板: 免费在线h视频| 果冻传媒高清完整版在线观看| 免费看成人aa片无码视频吃奶| 1000部拍拍拍18勿入免费视频软件 | 国产一区二区三区久久| 亚洲丝袜第一页| 国产香蕉一本大道| a级毛片免费全部播放| 小小视频在线版观看| 中文字幕乱码第一页| 日本三级带日本三级带黄国产| 久久精品日日躁夜夜躁欧美| 欧美zozozo人禽交免费大片| 亚洲成av人片在线观看无码| 毛片女人十八以上观看| 伊人久久国产精品| 精品久久久久久久九九九精品| 嘟嘟嘟www在线观看免费高清| 蕾丝视频在线看片国产| 国产又色又爽又刺激在线观看 | 亚洲伊人久久大香线蕉结合| 欧美疯狂性受xxxxx喷水| 亚洲综合精品香蕉久久网| 男女啪啪免费体验区| 午夜一级免费视频| 网站正能量www正能量视频| 国产一级视频播放| 蜜桃成熟时2005| 国产亚洲av综合人人澡精品| 韩国中文电影在线看完整免费版| 国产成人亚洲综合一区| 国产三级毛片视频| 国产日韩亚洲欧美| 国产精品网址你懂的| 国产成人精品免费视频大全| 麻豆视频免费播放| 国产成人高清视频| 黄网免费在线观看| 国产又粗又猛又爽视频| 青青青青草原国产免费| 国产亚洲欧美日韩精品一区二区|