- There are 3 non-common-cold coronaviruses that cause more serious illness, making a total of 7. They are: SARS-CoV-1, MERS, and SARS-CoV-2 - The 4 regular coronaviruses are 229E (alpha coronavirus), NL63 (alpha coronavirus), OC43 (beta coronavirus), HKU1 (beta coronavirus)
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- We don’t have a common cold vaccine because there’s too many - We don’t even know the cause of ~20% but they are presumed viral - Flu is more severe and has a vaccine because it’s only 3 virus families: A, B C. - All flu pandemics are from the type A, with the HxNy typology
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Most of the endemic ones are mild/non-fatal because they invaded humans several thousand years ago and did likely cause severe pandemics back then. The evolved to be less fatal and human immune systems also adapted and truly genetically vulnerable types got culled effectively.
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Exactly what I’ve been wondering. What’s to stop corona from going rhino and evolving 160 subtypes and effectively DDoSing us with variety, BUT remaining more dangerous than both colds and flus? We’ve got 4 mild and 3 severe coronaviruses already.https://twitter.com/Incept_shawn/status/1317932857256480769 …
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Note: a new Influenza A is still the most likely pandemic. So Covid19 isn’t even the pandemic we were most expecting. 2018 study cited in Pale Rider says 20% chance of 4 pandemics in next century, with high likelihood of one being a flu. 19th and 20th each had 2-3 flu pandemics.
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Thing I think I misunderstood before was you can’t assume sars-cov-2 will eventually evolve to be like one of 4 milder coronaviruses (via a less severe type providing immunity to the more severe type and out-evolving it). That’s like assuming lions will evolve to domestic cats.
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Lions and domestic cats have a common ancestor but lions don’t devolve to mostly harmless. Immunity to domestic cats (we can just physically dominate them) doesn’t give us any immunity to lions. Lions aren’t a pandemic scourge for other reasons.
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Interesting to consider the difference between a predator and a parasite. Small size and reproductive speed both matter. A lion is big enough that it can’t feed on you indefinitely keeping you alive. Let alone breed in you.
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Hmm there are only 45 recognized species of coronavirus total, of which 7 infect humans. For rhino viruses, there are 160 for humans alone. Possibly because rhinoviruses are among the smallest RNA viruses and coronaviruses are among the largest? Makes them less stable maybe?
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Sizes: Rhinoviruses: 30nm Flu viruses: 80-120nm Coronaviruses: 120nm but can range from 50 to 200 at extremes Smallpox: 300nm Domestic cats, leopards, lions/tigers, cattle. HIV is also 120nm range
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Hmm large mammals are actually a bad comparison. Viruses are as much smaller than bacteria (up to 100x) as insects are smaller than us. So we should map bacteria to predatory mammals and viruses to insects to get a better sense of proportions. Cholera = 2 μm = 2000nm
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After all some viruses, bacteriophages, infect bacteria. Sometimes making them worse. Apparently the CTXφ bacteriophage makes cholera more severe https://en.wikipedia.org/wiki/CTX φ_bacteriophage
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Lol, we’re just a sideshow in the viruses vs bacteria war for the planet . “It is estimated there are more than 10^31 bacteriophages on the planet, more than every other organism on Earth, including bacteria, combined.” https://en.wikipedia.org/wiki/Bacteriophage …
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Wonder if there’s any home-grade experiments or observations you can do with harmless bacteria that don’t require an electron microscope and won’t bring the FBI down on you. Hobby virology should be a thing.
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From first QT, sounds like most cold viruses don’t do enough damage to require adaptive immune response (specific antigens). I guess first response stuff like interferon works well enough?
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