问题
问答题 简答题
麻疹流行过程
答案
参考答案：
1.传染源
人是麻疹病毒的唯一宿主，麻疹患者是唯一的传染源。急性期患者是最重要的传染源。本病潜伏期为6~21天，平均为10天。
2.传播途径主要经呼吸道飞沫传播。患者咳嗽、打喷嚏时，病毒随排出的飞沫经口、咽、鼻部和眼结膜侵入易感者。3.易感人群人群普遍易感，易感者接触患者后90%以上发病，病后可获得持久免疫力。
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麻疹流行过程
参考答案：
1.传染源
人是麻疹病毒的唯一宿主，麻疹患者是唯一的传染源。急性期患者是最重要的传染源。本病潜伏期为6~21天，平均为10天。
2.传播途径主要经呼吸道飞沫传播。患者咳嗽、打喷嚏时，病毒随排出的飞沫经口、咽、鼻部和眼结膜侵入易感者。3.易感人群人群普遍易感，易感者接触患者后90%以上发病，病后可获得持久免疫力。
Big ocean fish have almost been endangered since the start of business fishing in the 1950s. The scientists found that the number of large fish has dropped by 90 percent in the past fifty years. The study took ten years. The researchers collected records from fishing businesses and governments around the world. The magazine Nature published(发表)th  e findings.The scientists say the common way called longline fishing is especially harmful to large fish. This way includes many fishing lines that are connected(连接) to one boat. If these lines are joined together, they can reach one hundred kilometers. They hold thousands of sharp metal hooks(钩) to catch fish. Longline fishing is especially common in the Japanese fishing industry. Records showed that Japanese boats used to catch about ten fish for every one hundred hooks. The study says longline fishing boats now might catch one fish per hundred hooks. The scientists say business fishing can destroy groups of fish much faster than in the past. It’s not the only worry that the number of large fish is becoming smaller and smaller. What’s worse, they are smaller in size than their ancestors(祖先). 根据短文内容完成表格，每空一词。 What is happening to ocean fish?
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