Understanding the Virus that Causes COVID-19, Animation
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Published 2020-03-27
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Voice by: Ashley Fleming
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Coronaviruses are a large family of enveloped, RNA viruses. There are 4 groups of coronaviruses: alpha and beta, originated from bats and rodents; and gamma and delta, originated from avian species. Coronaviruses are responsible for a wide range of diseases in many animals, including livestock and pets. In humans, they were thought to cause mild, self-limiting respiratory infections until 2002, when a beta-coronavirus crossed species barriers from bats to a mammalian host, before jumping to humans, causing the Severe Acute Respiratory Syndrome, SARS, epidemic. More recently, another beta-coronavirus is responsible for the serious Middle East Respiratory Syndrome, MERS, started in 2012. The novel coronavirus responsible for the Coronavirus Disease 2019 pandemic, COVID-19, is also a beta-coronavirus. The genome of the virus is fully sequenced and appears to be most similar to a strain in bats, suggesting that it also originated from bats. The virus is also very similar to the SARS-coronavirus and is therefore named SARS-coronavirus 2, SARS-CoV 2. At the moment, it’s not yet clear if the virus jumped directly from bats to humans, or if there is a mammalian intermediate host.
Coronavirus genome is a large, single-stranded, positive-sense RNA molecule that contains all information necessary for the making of viral components. The RNA is coated with structural proteins, forming a complex known as nucleocapsid. The nucleocapsid is enclosed in an envelope, which is basically a LIPID membrane with embedded proteins. From the envelope, club-like spikes emanate, giving the appearance of a crown. This is where the “corona” name came from.
The integrity of the envelope is essential for viral infection, and is the Achilles’ heel of the virus, because the lipid membrane can easily be destroyed by lipid solvents such as detergents, alcohol and some disinfectants. In fact, enveloped viruses are the easiest to inactivate when they are outside a host.
In order to infect a host cell, the spikes of the virus must BIND to a molecule on the cell surface, called a receptor. The specificity of this binding explains why viruses are usually species specific – they have receptors in certain species, and not others. Host jumping is usually triggered by mutations in spike proteins which change them in a way that they now can bind to a receptor in a new species.
The novel coronavirus appears to use the same receptor as SARS-coronavirus for entry to human cells, and that receptor is the angiotensin-converting enzyme 2, ACE2. Infection usually starts with cells of the respiratory mucosa, then spreads to epithelial cells of alveoli in the lungs.
Receptor binding is followed by fusion of the viral membrane with host cell membrane, and the release of nucleocapsid into the cell. The virus then uses the host machinery to replicate, producing viral RNAs and proteins. These are then assembled into new viral particles, called virions, by budding into intracellular membranes. The new virions are released and the host cell dies.
Uncontrolled growth of the virus destroys respiratory tissues, producing symptoms. Infection triggers the body’s inflammatory response, which brings immune cells to the site to fight the virus. While inflammation is an important defense mechanism, it may become excessive and cause damage to the body’s own tissues, contributing to the severity of the disease. In an otherwise healthy person, there is a good chance that the virus is eventually eliminated and the patient recovers, although some may require supportive treatments. On the other hand, people with weakened immune system or underlying chronic diseases may progress to severe pneumonia or acute respiratory distress syndrome, which can be fatal.
All Comments (20)
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Praying for the Physicians, Nurse practitioners, physician assistants, nurses, first responders, police force and those not mentioned. God bless them, protect them and empower them. Thank you for your courage.
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I never thought my bio class would be important but my goodness
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they did not mention it might have come from a lab...
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Thank you for sharing.You made me understand concepts that i never able to learn during dental college.I expected this video from you
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PLEASE GOD❤HELP US WE NEED YOU NOW MORE THAN EVER
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Sincere thanks to all scientists and medical reporters
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Thank you for providing information about it.
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We need to learn how to coexist or nature will find extreme ways to reclaim her space.
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Thank you for excellent declaration.,🌺
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If any entity were to design a biological weapon, this would be the one. 1. Highly contagious, 2. long infection - symptom period, 3. Lack of news about initial infections, 4. No known immunization, or cure.
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Thank you very much for your itellegant information
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The first time it jumped to a human from a pangolin, shut down the wet markets in China
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Anyone feel like me that having some kind of pain & worried it could be corona 🦠? 🤣😛
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Excellent class. Thank you.
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So the Corona Lipid membrane is easy to inactivate when outside a host but what about INSIDE?
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So in other words, extermination of bats. Got it.
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It's great and intetive information..... thanks
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I live in Northern Virginia 25min from Washington D.C My whole family got infected and it was due to doctor telling my brother to stay home. With no test he was super sick ! With a fever and because they told him not to get tested he spread it to our whole family and myself. When I got it I went to my primary care as directed to us from the health department I had to argue with the doctor to get tested! And we waited a whole week to get the results. The clinic was horrible to us. Only cared about getting paid. When I said my brother is terribly sick they only asked for his insurance and when I told them he was uninsured they just quoted how much everything would cost. Over 150 just to be seen and for a flu test first. He couldn’t afford it. We are now being monitored by phone calls from the health Department and dont get the luxury to test the rest of the family, stay in a hospital or get retested to help us know. We are being told if something gets worse call the on call nurse or call 911. They are going to tell us if we don’t have anymore symptoms to wait 3 days after that before we can leave the house for groceries. We get 3 phone calls.Me and my two brothers have survived the virus with a few symptoms no fever anymore but my parents have been sick for over a week and the cough and fever just won’t go away...
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Primary symptoms of COVID-19 are : - Cough - Fever - Shortness of breath
