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| DrG:
--- Quote from: gnuarm on March 18, 2021, 04:19:20 am --- --- Quote from: langwadt on March 17, 2021, 11:51:21 pm --- --- Quote from: Circlotron on March 17, 2021, 11:45:59 pm --- --- Quote from: Nominal Animal on March 16, 2021, 02:39:30 pm ---For example, if we use antibacterial detergents everywhere, and antibiotics for every bacterial and/or viral infection, then we actually provide evolutionary pressure for bacteria and viruses to evolve protection against them. Superbugs (antibiotic-resistant bacteria) didn't just appear out of nowhere; we forced bacteria to evolve that way. --- End quote --- I've heard some say that the above situation, rather than cause a new entity to evolve, instead wipes out all the weak versions and leaves the previously minority but very strong and therefore unaffected versions with the entire environment all to themselves so now they can multiply unchecked. Disclaimer - I have no particular understanding of these things. --- End quote --- isn't that basically the evolve in evolution? --- End quote --- Evolution consists of two separate things, mutation and selection. There is no guiding force causing mutations. They happen randomly and constantly resulting in a genome population with variation. When these mutations result in poor performance in the environment those organisms reproduce less often and the frequency of the genes they carry are reduced. When the mutations result in better survivability in the environment the frequency of the gene increases. In a disease population that is not wide spread (no where near herd immunity numbers) there is no competition. Many strains of the disease can spread without influence on one another. There is no real competition. Once herd immunity levels are approached only a significant mutation that prevents existing antibodies from attacking the virus will be able to spread widely. That is why we need to continue to take all precautions to minimize the spread of the disease; so the disease can be brought to Australian levels where it can be tracked and traced out of existence. --- End quote --- I certainly agree with your final sentence – completely, but if I can add some other information (as I see it). We can cause mutations – chemicals and radiation, for example. The virus (SARS-CoV-2) is not alive. It requires a living cell to reproduce. It binds to the cell and hijacks the cell to follow its RNA instructions, which includes making copies. Unabated, enough cells get hijacked and you are in trouble. When a copy is made, it can have an error in the sense that the newly made virus is not identical to the first one – that is the mutation. The more copies that are made, the more mutations will occur. The mutated virus has to be able to continue to make copies and those copies include the error. That’s how we get a “variant”. Many mutations have little biological significance. Some can, potentially, make it much more lethal. In fact, they can fade out because they kill the host so quickly, there is little chance to transmit to another host. Some mutations can be more transmissible (more contagious). The virus binds to a site on the cell and some mutations can make that bond stronger or easier to bind to the cell. In an evil sense, the worst case scenario is a very transmissible and very lethal virus, but slowly lethal, or lethal in only some people. A vaccine can be less effective against a variant, but it is really the immune system activation by the vaccine that is not recognizing the variant as well as the “original” – that is the thinking. This is expected to happen the longer the virus is active and the counter is to change the vaccine so that what is produced by the vaccine – that is the immune stimulation, is better targeted against the variant. The two mRNA vaccines are little more than mRNA and some lipids to get it into your cells. There, the mRNA instructs the cells to make a compound that stimulates our immune system in a way that produces antibodies that can neutralize the virus. Even when the antibodies are gone the immune system has a “memory” such that it can recognize the virus can produce more of those antibodies quickly. If they need to be tuned up, you can change the mRNA. Moderna has already done that and has requested a clinical trial for a new formulation that is designed to be more effective against variants. The J&J vaccine (the one-shot, no big cooling needed) uses a modified adenovirus (harmless and can’t reproduce) to get into the cells to have them make a substance that will stimulate the same kinds of immune response. Novovax (nearly approved) actually contains bits of harmless virus-like spikes. Again, these get recognized by the immune system and it outputs antibodies. In each case, the vaccine can be tuned to produce an immune response better targeting a variant. The big fear, however, is that we don’t get it under control with vaccination; we could end up in a whack-a-mole situation. If we don’t screw up, we will overcome this one and be better prepared for the next one. But that is a big “if”. Even though in the US we are up to some 2 million shots / day, and increasing, I worry. Moreover, it is absolutely a global situation that requires global eradication/control. Sorry to go on and on but I am trying to set up an old Linksys WRT54G router - remember those? Well, I feel like I have forgotten whatever I once knew about the $!#@ things!. |
| gnuarm:
--- Quote from: Circlotron on March 18, 2021, 04:33:59 am --- --- Quote from: gnuarm on March 18, 2021, 04:19:20 am ---When these mutations result in poor performance in the environment those organisms reproduce less often and the frequency of the genes they carry are reduced. When the mutations result in better survivability in the environment the frequency of the gene increases. --- End quote --- If we substitute the word "humans" for "organisms", from a purely logical point of view, by vaccinating ourselves it would appear we are interfering with evolution's efforts to refine the human race. Note I said logical, not ethical. --- End quote --- Not sure what you mean by "interfering". Creating and using vaccines is part of our survival process. That's perfectly natural in the context of our own evolution. BTW, evolution is not a thing and doesn't have "efforts". It just happens. |
| Zero999:
--- Quote from: NiHaoMike on March 17, 2021, 10:42:36 pm --- --- Quote from: Zero999 on March 16, 2021, 06:47:46 pm ---I do agree we need to cut our use of antibiotics and develop new ones. It's possible the next pandemic could be caused by an antibiotic resistant bacterium. --- End quote --- --- Quote from: madires on March 16, 2021, 03:07:07 pm ---Antibiotics are meant to deal with bacteria, not viruses. But it's true that we use way too much antibiotics, not just in human and veterinary medicine but also in industrial livestock farming which is possibly the larger threat. --- End quote --- Indeed, they should rapidly phase out factory farming. I hope that if factory farming causes another pandemic, it would be one that decimates factory farms but cause little or no harm to humans or sustainably raised animals. --- End quote --- Factory farming is generally bad, as disease can spread rapidly and pathogens have plenty of opportunties to mutate, but there is one benifit of keeping animals indoors: it helps to keep them away from pathogen reservoirs in wild animals. We need lower density farming and stricter controlls of antibiotics used on livestock. --- Quote --- --- Quote from: Nominal Animal on March 17, 2021, 01:53:18 pm ---Particularly funny/weird/sad is that the most effective way to stop the spread of pandemics is to restrict human movement, drastically: no exceptions, even for the super rich or politicians. So simple, yet so costly and difficult. Proven to save lives, but how do you calculate potential losses, or how much is a single avoidable death worth? How do you balance the near-term loss of life with the long-term loss of life due to increased statistical financial hardships? It is not easy. --- End quote --- Hence why I'm strongly against reopening schools early, since school has become bloated and overpriced. In its place, we could have online learning services instead. Hands on activities (e.g. science experiments) could be done by sending kits to the students or small workshops could be opened if that's not practical, done in such a way that possible spread would be very limited. --- End quote --- I agree that the school is pretty crappy these days, but it's not just about academia, but socialising and learning to obey rules. It also negatively impacts parents who can't work from home. Here in the UK we opened schools last, after the first lockdown, but this time they've been the first thing to open, whilst restaurants, hair dressers, non-essential retail are still closed. Lots of it is political and this isn't the place for that discussion. --- Quote from: gnuarm on March 18, 2021, 12:38:37 am --- --- Quote from: Zero999 on March 16, 2021, 08:02:22 pm --- --- Quote from: TimFox on March 16, 2021, 07:44:59 pm ---The best strategy for a new pathogen is to become less lethal and more infectious, thus increasing their numbers without killing off their hosts. --- End quote --- Unfortunately the less lethal part doesn't apply to pathogens which spread in a/presymptomatic people, or via a third party. For example, HIV has a 100% mortality rate, without treatment and spreads rapidly in healthy people, so it has no incentive to become less deadly. The same is true with SARS-Cov 2, which whilst fortunately is several orders of magnitude less deadly, also spreads in healthy people. Unfortunately there's mounting evidence to suggest the B1525 variant discovered in the UK, is not only more transmissible, but more deadly, than the original one. A pattern which seems to be repeated in other new variants. I know it's only wackypedia (I'm lazy) so check the references. https://en.wikipedia.org/wiki/Variants_of_SARS-CoV-2#Overview_table --- End quote --- If you think about the mechanics for a moment, you will realize most increases in transmissibility will also make a given infection more serious or lethal. The most likely change that improves transmissibility is to more readily invade a cell or reproduce in larger numbers or faster so that lower initial numbers of viruses are more likely to create an infection. They will also make the disease more serious and deadly. So, no surprise. --- End quote --- It's not certain either way. If the virus evolves to infect the upper respitory tract, rather than the lungs, it'll be less lethal. I think in this case, with the newer variants of COVID-19, your statement is correct: it's more readily invades cells and reproduces faster, so the minimum infectious dose is lower, which also makes it more lethal. --- Quote from: gnuarm on March 18, 2021, 04:19:20 am --- --- Quote from: langwadt on March 17, 2021, 11:51:21 pm --- --- Quote from: Circlotron on March 17, 2021, 11:45:59 pm --- --- Quote from: Nominal Animal on March 16, 2021, 02:39:30 pm ---For example, if we use antibacterial detergents everywhere, and antibiotics for every bacterial and/or viral infection, then we actually provide evolutionary pressure for bacteria and viruses to evolve protection against them. Superbugs (antibiotic-resistant bacteria) didn't just appear out of nowhere; we forced bacteria to evolve that way. --- End quote --- I've heard some say that the above situation, rather than cause a new entity to evolve, instead wipes out all the weak versions and leaves the previously minority but very strong and therefore unaffected versions with the entire environment all to themselves so now they can multiply unchecked. Disclaimer - I have no particular understanding of these things. --- End quote --- isn't that basically the evolve in evolution? --- End quote --- Evolution consists of two separate things, mutation and selection. There is no guiding force causing mutations. They happen randomly and constantly resulting in a genome population with variation. When these mutations result in poor performance in the environment those organisms reproduce less often and the frequency of the genes they carry are reduced. When the mutations result in better survivability in the environment the frequency of the gene increases. In a disease population that is not wide spread (no where near herd immunity numbers) there is no competition. Many strains of the disease can spread without influence on one another. There is no real competition. Once herd immunity levels are approached only a significant mutation that prevents existing antibodies from attacking the virus will be able to spread widely. That is why we need to continue to take all precautions to minimize the spread of the disease; so the disease can be brought to Australian levels where it can be tracked and traced out of existence. --- End quote --- We don't need to completely get rid of it, to get life back to normal. Fortunately serious illness due to reinfection is rare, so once we have herd immunity, the number of deaths will drastically fall. It's also rarely fatal in the young, so it's highly likely it'll just become like flu, or perhaps even milder, since it doesn't mutate quite so rapidly. I doubt the US or Europe will be able to do as the Australians have done. Australia is quite well isoleted from the rest of the world and has a very low population density. People here in the UK often say we should have done what Australia did, but even through we're geographically an island, we're not really, since there's a tunnel linking us to Europe and we're too dependant on people crossing the border to completely close it. |
| Nominal Animal:
--- Quote from: Circlotron on March 17, 2021, 11:45:59 pm --- --- Quote from: Nominal Animal on March 16, 2021, 02:39:30 pm ---For example, if we use antibacterial detergents everywhere, and antibiotics for every bacterial and/or viral infection, then we actually provide evolutionary pressure for bacteria and viruses to evolve protection against them. Superbugs (antibiotic-resistant bacteria) didn't just appear out of nowhere; we forced bacteria to evolve that way. --- End quote --- I've heard some say that the above situation, rather than cause a new entity to evolve, instead wipes out all the weak versions and leaves the previously minority but very strong and therefore unaffected versions with the entire environment all to themselves so now they can multiply unchecked. Disclaimer - I have no particular understanding of these things. --- End quote --- Yes, but bacteria can exchange DNA "horizontally" ("horizontal DNA transfer" and "horizontal gene transfer" in literature), across different types, when in close proximity (in the same patient). This means that to get a new drug-resistant strain of bacteria, all you need is a patient with two or more bacterial infections, one of which is a drug-resistant strain. (Obviously, it does not always happen, you need some bad luck too.) Viruses exchange RNA, if two different types infect the same cell. This is a major way how viruses and bacteria evolve. There are some very interesting scientific papers on this, for example Juhas, M. "Horizontal gene transfer in human pathogens", Crit Rev Microbiol. 2015 Feb;41(1):101-8. Not my field, but the abstracts tell pretty well what the researchers are investigating. |
| jpanhalt:
@Nominal Animal That ability to promiscuously pick up DNA from its environment was well know for the Neisseriaceae, which includes Neisseria gonorrhoea, of course. Easy to remember. |
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