Baby Astronaut Posted January 26, 2009 Share Posted January 26, 2009 More seriously, what's the longest a single virus can exist in the host? Once a duplicate virus has been manufactured and released by a cell, does it have an expiration date, a time period in which it must reach an uninhabited cell and duplicate, before it loses its ability to be sprung into action by entering a healthy cell? Also, some medicines work by disabling the cell's borrowed manufacturing process that a virus depends on. I'd assume the medicine has a time limit, and once the cells' process are functioning again, the virus in stasis has a chance to become functional again -- unless by then it's already "dead". Link to comment Share on other sites More sharing options...
ecoli Posted January 26, 2009 Share Posted January 26, 2009 There is no expiration date, and it largely depends on the type of virus. For example, the Herpes virus can hang out in the neural ganglia acting as a reservoir for the indefinite life time of the host. Link to comment Share on other sites More sharing options...
Sisyphus Posted January 26, 2009 Share Posted January 26, 2009 Inasmuch as a virus outside of a cell is more like an inanimate, giant molecule than a living thing, wouldn't there really be no set lifespan, as long as there is nothing actively destroying it? Link to comment Share on other sites More sharing options...
Baby Astronaut Posted January 26, 2009 Author Share Posted January 26, 2009 There is no expiration date, and it largely depends on the type of virus. For example, the Herpes virus can hang out in the neural ganglia acting as a reservoir for the indefinite life time of the host. Sure, but instead of the whole colony, what if you simply tracked one individual virus? Inasmuch as a virus outside of a cell is more like an inanimate, giant molecule than a living thing, wouldn't there really be no set lifespan, as long as there is nothing actively destroying it? That's what I've heard, but various searches on the internet didn't turn up anything to confirm it. My thought is it would be inanimate like a seed of a tree, until spurred to action when the proper catalysts hit it. Still, I can't help but wonder if a lone virus would have a "shelf life" because of medicines that cut off its reproduction in cells within the host. Wouldn't such medicine be useless if the virus were able to simply "hang out" until the medicine's effects wore off? Link to comment Share on other sites More sharing options...
Mokele Posted January 26, 2009 Share Posted January 26, 2009 The seed analogy is a good one. A virus outside a cell is pretty much an inert package of proteins and genetic material, waiting to land. Just like seeds, they can decay or be eaten by various things. Some species are fragile (like HIV) and quickly break down, while others are durable and can last a long, long time. In the body, it's a bit different, mostly because the body has active defenses that not only target virii, but will generally just scoop up and destroy anything they don't recognize. So even if the virus was 'safe' from medicine by lurking passively outside a cell, chances are a wandering macrophage would just devour it anyway. Mokele Link to comment Share on other sites More sharing options...
Baby Astronaut Posted January 26, 2009 Author Share Posted January 26, 2009 The seed analogy is a good one. A virus outside a cell is pretty much an inert package of proteins and genetic material, waiting to land. Just like seeds, they can decay or be eaten by various things. Some species are fragile (like HIV) and quickly break down, while others are durable and can last a long, long time. Thanks Mokele. It's the quantification of a "long, long time" I'm shooting for (Interesting, though. A virus can really just decay on its own?) Link to comment Share on other sites More sharing options...
npts2020 Posted January 27, 2009 Share Posted January 27, 2009 I wonder if the "lifespan" of a virus can be compared to that of an archaeon? I have read that archaeons can survive inside solid rock for tens of thousands of years. Link to comment Share on other sites More sharing options...
Mokele Posted January 27, 2009 Share Posted January 27, 2009 A virus can really just decay on its own? Anything made of proteins, nucleotides, etc can and will decay on its own from just environmental effects. Hence why our bodies constantly re-make and repair themselves. Link to comment Share on other sites More sharing options...
Sisyphus Posted January 27, 2009 Share Posted January 27, 2009 Anything made of proteins, nucleotides, etc can and will decay on its own from just environmental effects. Hence why our bodies constantly re-make and repair themselves. Suppose, though, you put them in the most pampering, inactive environment possible, so you could more or less exclude external effects (assuming that's even possible). They would still decay eventually, but it would have to be due to stuff like molecular instability, right? I wonder how long that would take for the most tenacious viruses. What's the natural half life of your average rhinovirus? Link to comment Share on other sites More sharing options...
scrappy Posted January 27, 2009 Share Posted January 27, 2009 I wonder if the "lifespan" of a virus can be compared to that of an archaeon? I have read that archaeons can survive inside solid rock for tens of thousands of years. I hope this post is not too far OT, but I think it is relevant to mention here that bacteria of the Streptococcus genus managed to survive unprotected on the moon for 30+ years. Astronaut Pete Conrad made this cogent observation: I always thought the most significant thing that we ever found on the whole...Moon was that little bacteria who came back and lived and nobody ever said [anything] about it. Intuitively, I would expect viruses to survive almost indefinitely in such a harsh environment. Link to comment Share on other sites More sharing options...
John Cuthber Posted January 27, 2009 Share Posted January 27, 2009 I know that people have extracted DNA from old things but that Dinosaur DNA from amber remains in the realms of science fiction. What's the oldedts DNA found and is it reasonable to assume that viruses might last roughly that long? Link to comment Share on other sites More sharing options...
CharonY Posted January 27, 2009 Share Posted January 27, 2009 The virus particle itself outside the body is not likely to maintain integrity for very long. The maximum is around a few weeks in humid environments. But inside the body it is a different story. Though of course the stables form is the one we all carry around with us: integrated into genomes. Link to comment Share on other sites More sharing options...
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