What is a pandemic?
什麼叫大流行病？
What is a pandemic? To understand that, we need to first understand where they start.
什麼叫大流行病？要想知道答案，我們首先需要了解一下它是如何產生的。
Jennifer Rohn (University College London) An epidemic is simply an outbreak of inflection in a localized area. A pandemic is when that inflection spreads to multiple countries around the world.
Jennifer Rohn (倫敦大學學院)： 流行病只是在局部地區爆發的一種傳染病，當流行病的疫情蔓延到全球多個國家時，即為大流行病。
And while on the one hand, we are better protected than before. On the other, our changing society brings together a host of other challenges.
一方面，我們比以前得到了更好的保護；另一方面，我們不斷變化的社會又為我們帶來了一系列挑戰。
Jennifer Rohn (University College London)： In this day and age, all you need is one person at the airport and you can infect the whole world.
Jennifer Rohn：當今這個時代，只要一個病毒攜帶者出現在機場，疫情就可能會擴散到全世界。
The majority of pandemics to date have been strains of influenza Through pandemics can be any type of infection, usually a virus. Many new or novel viruses come from animals. They can pass on to humans after close contacts and a process called zoonotic spillover.
迄今為止的大流行病大多是流感的菌株。雖然大流行病可能體現為任何方式的感染，但其中主要還是病毒型感染。很多新型病毒都來源於動物，它們可以通過密切接觸的途徑傳播給人類，這種傳播過程叫做人畜共患。
Jennifer Rohn (University College London)： And when that happens, sometimes the virus is not very transmittable, because it is suited to circulating only in animals. But sometimes we see ones that can transmit from person to person and they can be quite efficient at doing this. And in that case, an outbreak can become an epidemic as it grows and there is a chance that it could spread more widely.
Jennifer Rohn：而且當這種情況出現時，有時候這種病毒的傳播能力並不強，因為它只會在動物之間傳播。但有時候，我們會發現一些病毒可以在人之間傳播，而且他們的傳播能力很強。隨著病毒的傳播，疫情可能會爆發成為流行病，還可能會更廣泛地傳播，進而爆發成大流行病。
This is what happened in the 2009 swine flu pandemic. A pig influenza virus is moved into people. Pig viruses are similar to human viruses and that allows human to human transmission to happen quicker. More than a decade has passed since the 2009 pandemic and the world’s population has grown, as have the risks of passing viruses between people.
這就是2009年豬流感大流行時的情形。一種豬流感病毒傳播給了人類。豬的流感病毒與人的流感病毒相似，這使得這種病毒在人與人之間傳播的更快。2009年的豬流感大流行已經過去十多年了，世界上的人口越來越多，人與人之間的病毒傳播風險也越來越大。
Jennifer Rohn (University College London)： We are getting more and more people on the planet, we are having more globalization. People are travelling from country to country more than ever before. So, these are kind of things that will cause pandemics to happen.
Jennifer Rohn：地球上的人越來越多，全球化程度也越來越高。人們從一個國家到另一個國家的旅行也比以往任何時候都多，這些都是可能會導致大流行病發生的事情。
Medicine technology and communication have all improved with time, and serious outbreaks require international cooperation. But experts say the real question isn’t if a new pandemic strikes but instead how bad it could be.
隨著時間的推移，醫學技術和通訊技術都在進步，疫情嚴重時需要國際間的共同合作。但專家表示，目前真正需要關注的問題不在於是否會有新的大流行病爆發，而在於爆發的大流行病會帶來多麼嚴重的後果。