Complete the subtitles Watch the video, then go through the text and complete the missing subtitles to have a clear structure of the expository writing. 1. Naming By now you’ve probably heard of COVID-19 , or co rona vi rus d isease discovered in 2019, which is responsible for a global pandemic . Thus far the main country affected has been China, but it has spread to a number of other countries around the world to a varying degree. The virus was initially referred to as the 2019-nCoV, or the 2019 novel coronavirus and was informally called “Wuhan coronavirus”. The World Health Organization named the disease COVID-19 because it doesn’t refer to a geographical location, an animal, a person or group of people -- all of which can lead to stigma( 污名 ). They also wanted to make it pronounceable and related to the disease which is not an easy task! The virus was officially named SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2 ( 严重急性呼吸综合征病毒 2 型 ) , because it’s genetically very similar to the SARS coronavirus which was responsible for, well, the Severe Acute Respiratory Syndrome, or SARS, outbreak in 2002 (2003). So SARS-CoV-2 causes COVID-19. 2. ___________________ Now, coronaviruses that circulate among humans are typically benign , and they cause about a quarter of all common cold illnesses. But occasionally, coronaviruses that circulate in an animal reservoir ( 动物宿主 ) mutate just enough to where they’re able to start infecting and causing disease in humans, if they’re given an opportunity. In 2002 SARS was a coronavirus that hopped over from bats to civets ( 果子狸 ) , which is a cat-like mammal; and then over to humans. And in 2012, there was MERS, which was a coronavirus that hopped over from bats to camels a few decades ago and then circulated among camels for quite some time before eventually infecting humans. COVID-19 most likely also started with bats, but this time the intermediate host was probably a pangolin ( 穿山甲 ) , an animal that looks like a cross between an anteater ( 食蚁兽 ) and an armadillo ( 犰狳 ) . That’s based on the fact that scientists identified a coronavirus in pangolins that’s a 96% genetic match to SARS-CoV-2. Sadly, pangolins are heavily trafficked around the planet , largely because people believe that their scales have healing properties. And because they’re moved around the world rather than left in the wild, there are ample opportunities for a coronavirus to go from a pangolin to a human. 3. ___________________ As of February 11, 2020 , there have been 43,103 cases of COVID-19 and 1,018 deaths, with a fatality rate ( 死亡率 ) of 2.4% , according to WHO. The vast majority of cases and deaths have occurred in China. For some perspective , the 2002 SARS outbreak resulted in 8,098 cases and 774 deaths, so the fatality rate was around 9.6% . And the 2012 MERS outbreak results in 2,494 cases and 858 deaths, bringing the fatality rate to 34% . Finally, for the 2014 Ebola outbreak, which was not due to a coronavirus, there were 28,639 cases and 11,316 deaths. The fatality rate was a whooping 40% ! 4. Microscopic Level At a microscopic level, coronaviruses are single strand positive sense RNA viruses with protein spikes on their surface ( 表面有刺突糖蛋白、基因组为线性单股正链的 RNA 病毒 ) that look a bit like a crown under a microscope. In fact, “corona” is Latin for crown. Besides just looking majestic, these spikes allow the virus to invade cells lining the respiratory tract ( 呼吸道 ) and lungs. After binding, the coronavirus enters and takes over the cellular machinery to make more and more copies of itself so it can spread to the surrounding cells and get into the mucus ( 黏膜 ). 5. ___________________ Sometimes the infection is mild , and some people don’t develop any symptoms at all. For others, they can develop symptoms that can range from mild symptoms like fever , cough , and shortness of breath , all the way to serious problems like pneumonia ( 肺炎 ). Severe lung damage can cause acute respiratory distress syndrome, or ARDS ( 急性呼吸窘迫征 ), which occurs when the lung inflammation is so severe that fluid builds up around and within the lungs. The severe infection can cause septic shock ( 脓毒性休克 ), which happens when the blood pressure falls dramatically and the body’s organs are starved for oxygen . ARDS and shock are the main cause of death for people with the infection, and this is more likely to occur in those over the age of 60, smokers, and people with previous medical conditions like hypertension ( 高血压 ). 6. ___________________ In addition to causing disease, coronaviruses can spread quickly. Usually the virus spreads when people cough or sneeze, and tiny droplets containing the virus are released. These droplets can land on another person’s mouth, nose, or eyes, and that allows the virus to enter a new person. Virus can also be found in a person’s stool ( 粪便 ), and in rare situations coronavirus has been transmitted from one apartment to another within a residential building. This was also seen in the 2002 SARS epidemic . At that time, faulty plumbing allowed virus-containing fecal matter originating from one person’s apartment to drift from drainage pipes back up into fixtures like sinks and toilets within other apartments in the same building. Not only this created a terrible smell but also allowed the virus-containing droplets to deposit on bathroom surfaces, ultimately causing people in those apartments to get ill. Something similar may have happened with COVID-19, and this is being actively investigated . Once a person is infected, symptoms develop an average of 5 days later. This is called the incubation period ( 潜伏期 ). However the incubation period varies from person to person, and in some studies, it lasted as long as 24 days! Now there’s debate about whether or not asymptomatic ( 无症状的 ) people can spread the disease, because these people typically have low levels of circulating virus. But even if they do, asymptomatic transmission likely plays a minor role in the overall epidemic . Viruses are given a reproductive number or R-naught (R0- 基本传染数 ) based on how quickly they spread, and person to person transmission has been confirmed both in and outside of China. An R-naught of 1 means that an infected person passes it on to 1 new person, an R-naught of 2 means that 1 person spreads it to 2 new people, and so forth . If the R-naught is below 1, the infection peters out , if it’s 1 it stays steady, and if it’s above 1, then it continues to spread. The current estimate for the SARS-CoV-2 R-naught is between 1.4 and 3.9 . Of course that’s an average, with some spreading the disease less, and others -- called super-spreaders -- spreading the disease at a much much higher rate. The exact cause of these super-spreaders is unclear, perhaps they are just in contact with more folks, perhaps their bodies naturally shed more virus, or perhaps there’s some other reason altogether. 7. Diagnosis & Treatment To confirm the diagnosis, there should be a Reverse Transcription Polymerase Chain Reaction or RT-PCR tests ( 逆转录聚合酶链式反应, RT-PCR ), which is a quick test used in many labs and hospitals that can detect very small amounts of viral RNA. Treatment is focused on supportive care -- providing fluids, oxygen, and ventilatory support ( 通气支持 ) for really ill people. There’s also some early data showing that three medications are highly effective against SARS-CoV-2 in the laboratory setting. These medications are chloroquine ( 氯喹 ), an anti-malarial drug ; ritonavir ( ) , an anti-HIV medication; and remdesivir ( 瑞德西 ) , an antiviral drug previously used against Ebola. Remdesivir was given to the first US patient with COVID-19 on day 11 of his illness as he was clinically worsening , and he began to improve the very next day. Large scale clinical trials using remdesivir are already underway in China. 8. ___________________ Unfortunately there’s no vaccine currently available to protect against COVID-19. At best, it looks like a vaccine will be many months away. So for now the goal is to avoid human to human transmission, starting with isolating people with COVID-19 . Coronaviruses don’t usually spread over long distances in the air, but they can travel roughly 3 feet or 1 meter from one person to another on tiny droplets of saliva ( 唾液飞沫 ), which are produced when someone’s coughing or sneezing. In addition, some strains of coronavirus can survive on surfaces for over a day. With that in mind, if you’re a healthy person living in a non-outbreak area, the recommendation is to avoid travel to disease outbreak areas, generally stay away from crowded places, and stay at least 6 feet or 2 meters away from anyone with symptoms. Wearing a surgical mask is not recommended because the general risk of getting COVID-19 in these settings is so low. As always, careful hand washing is the key and it should be done with soap or alcohol-based hand sanitizers and scrubbing . Also, avoid touching your eyes, nose, and mouth -- this is the area, known as your T-zone is a common entry point for viruses into the body. For healthcare workers who are around people with COVID-19, the recommendation is to apply droplet and contact precautions ( 采取避免飞沫和接触传播的隔离措施 ). That includes wearing personal protective equipment like a clean, dry surgical mask, gloves, long-sleeved gowns , and eye protection like goggles or a face shield. When performing a procedure that generates aerosol ( 气溶胶 ), like tracheal intubation ( 气管插管 ), bronchoscopy ( 支气管镜检 ), CPR, or noninvasive ventilation ( 无创通气 ), it’s important to wear a N95 respirator ( 口罩 ). This prevents 95% of the small particles, like respiratory droplets , from passing through . 9. Recap All right, there’s a quick recap . The SARS-CoV-2 virus causes a respiratory disease called COVID-19 . The virus probably originated from bats, then went to pangolins as an intermediate host , and finally to humans. The virus travels in respiratory droplets and enters the body via the mouth, nose, or eyes.