北師大版高中英語模塊7--Unit 21 Lesson3-1

[00:02.37]Unit21 Human BiologyLesson3 Epidemics Explained [00:09.57]Epidemics throughout history [00:12.34]With new health threat on the rise, [00:14.33]James Madison looks at epidemics [00:16.13]throughout history. [00:18.09]Bacteria and viruses have been around [00:20.34]since the beginning of life [00:21.78]on Earth and many of today's diseases [00:24.10]have existed as long as humans have. [00:27.33]It's important to look at the spread [00:28.88]of diseases throughout history to discover [00:31.24]the causes and effects of epidemics. [00:34.41]Epidemics are described in historical accounts [00:37.13]as early as 430 BC [00:39.87]and one of the earliest on record [00:41.68]is Justinian's Plague. [00:43.62]It happened about 500-550 [00:47.64]as Roman Emperor Justinian [00:49.87]was attempting to rebuild and acquire more land [00:52.47]for the Roman Empire. [00:54.03]It swept through North Africa, [00:55.71]the Middle East and Europe. [00:58.15]Scientists now think taht Justinian's Plague [01:00.83]was actually a disease called bubonic plague. [01:04.34]They estimate that between 25% and 50% [01:07.95]of the area's population died [01:10.08]from the disease and think that the epidemic [01:12.34]was one of the key causes [01:13.70]of the fall of the Roman Empire. [01:14.91]

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