<tt id="6hsgl"><pre id="6hsgl"><pre id="6hsgl"></pre></pre></tt>
          <nav id="6hsgl"><th id="6hsgl"></th></nav>
          国产免费网站看v片元遮挡,一亚洲一区二区中文字幕,波多野结衣一区二区免费视频,天天色综网,久久综合给合久久狠狠狠,男人的天堂av一二三区,午夜福利看片在线观看,亚洲中文字幕在线无码一区二区
          您現在的位置: Language Tips> Audio & Video> Special Speed News  
           





           
          Fighting Exotic Newcastle disease
          [ 2007-12-18 10:13 ]

           

          Download

          This is the VOA Special English Agriculture Report.

          Newcastle disease is a bird virus found in many parts of the world. Many kinds of birds carry it. But it especially affects chickens and a few others.

          It spreads very fast and there is no treatment. Many birds die without appearing sick. The infection does not present a serious health threat to humans. But economic losses can be huge as birds are destroyed and trade is restricted to contain outbreaks.

          Exotic Newcastle disease, also known as END, is the most severe form of Newcastle disease.

          Experts say the easiest way to prevent the virus is to import birds from flocks that are disease-free. Vaccines are also used, although experts say the virus may sometimes cause deaths even in vaccinated flocks.

          In the United States, the Agriculture Department says poultry birds are rarely vaccinated against the virus unless an outbreak happens. The most recent outbreak began in 2002 in California. State officials said it cost more than one hundred sixty million dollars to fight. California was declared disease-free the next year, after the killing of more than three million birds.

          The Global Invasive Species Database says signs of the disease may appear from two to fifteen days after a bird is infected. An infected hen lays fewer or no eggs, or eggs with thin shells. A sick bird may develop breathing and intestinal problems and twist its head and neck. It may run around in circles or not move at all.

          Exotic Newcastle disease spreads fastest among birds kept close together. The virus is spread through bird droppings and fluid from the nose, mouth and eyes.

          To control outbreaks, experts advise quick destruction of infected flocks. They also advise limiting entry to farms and disinfecting vehicles as they come and go.

          People can also transport the virus on their shoes and clothes. The virus can survive several weeks in a warm, moist environment. And there seems to be no limit if it is frozen. But ultraviolet rays in sunlight can kill it.

          To reduce infection risks, the Organization for World Animal Health warns against keeping any pet birds on a farm. It even advises against hiring pet bird owners as farm workers. The Agriculture Department says Amazon parrots, for example, can spread the virus for more than a year but not get sick.

          And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. I'm Steve Ember.

          (Source: VOA 英語點津姍姍編輯)

           
           
          相關文章 Related Stories
           

           

           

           
           

          本頻道最新推薦

               
            Fighting Exotic Newcastle disease
            Medvedev nominated as Putin's successor
            Bush: Iran has no need to enrich uranium
            Bike Beijing, Green Olympics
            Interview with Mrs Leavitt

          論壇熱貼

               
            開個題目大家扯:hotel & restaurant
            追求某人
            請教工商年檢如何翻譯
            How to translate “中國老字號”into English?
            "港股直通車"怎么翻譯?
            兩免一補怎么說?




          主站蜘蛛池模板: 国产精品麻豆成人av网| 中国明星xxxx性裸交| 人人妻人人澡人人爽国产一区| 亚洲精品中文字幕码专区| 精品天堂色吊丝一区二区| 久久精品不卡一区二区| 国产精品无码无在线观看| 亚洲国产精品成人av网| 国产AV嫩草研究院| 国产精品毛片在线完整版| 亚洲国产精品综合久久20| 亚洲成av人片在www色猫咪| 欧美一区二区三区成人久久片| 精品亚洲高潮喷水精品视频| 亚洲人成线无码7777| 久久精品娱乐亚洲领先| 国产精品乱码人妻一区二区三区| 亚洲人成伊人成综合网无码| 亚洲欧美国产va在线播放| 中文字幕一区有码视三区| 亚洲精品色哟哟一区二区| 国产乱女乱子视频在线播放| 亚欧美闷骚院| 久久精品国产亚洲av天海翼| 国产精品老熟女露脸视频| 亚洲成A人片在线观看的电影| 国产99视频精品免费观看9| 美腿少妇资源在线网站| 在线看免费无码的av天堂| 亚洲av优女天堂熟女久久 | 高清无打码一区二区三区| 国产亚洲精品成人aa片新蒲金| 色狠狠色婷婷丁香五月| 18禁黄无码免费网站高潮| 女人高潮被爽到呻吟在线观看| 亚洲狼人久久伊人久久伊| 影音先锋女人AA鲁色资源| 99久久精品免费看国产| 男女啪啪激烈无遮挡动态图| 日本精品视频一区二区| 18岁日韩内射颜射午夜久久成人|