Have been reading up on virology and the history of infectious disease. You’d think we know a great deal about them. In medical school, we learned about the 250 or so viruses that infect people. We learned less about the trillions of microbes, three pounds worth, each person carries. Maybe 40,000 species. We don’t know much about them. They help us digest 10 percent of our calories and extract certain vitamins.
Viruses are weird. Most of them infect bacteria and have no effect on us. No one knows how many different ones there are - estimates range from 300,000 to a trillion. They can’t propel themselves and are inert outside a cell, waiting to be collected off a surface or in the air. In 1986, a student decided to look for them in seawater, which was thought to be a waste of time. She found each quart contains up to 100 billion viruses. If ocean viruses alone were laid end to end, it would stretch for ten million light years. This is a lot more than the DNA in your one body, which if stretched end to end would go beyond Pluto.
A virus found in permafrost in 2014, frozen for 30,000 years or so, was still active when injected into an amoeba. Viruses spread very quickly. A volunteer fitted with a device to mimic a virus, using ultraviolet dyes, showed at a cocktail party to go everywhere - the hands, head, upper body of everyone, doorknobs, sofa cushions, food — since the average adult touches their face sixteen times an hour. A virus can spread through an office building in four hours. But kissing doesn’t spread them effectively, they need other physical touch. A survey of subway trains showed metal poles to be fairly clean; but plastic handgrips and seat fabric to be highly populated.
We know so little about so many microorganisms that it seems prudent to expect future outbreaks and prepare for them. Much of the microbiome undoubtedly has positive effects, but no one wants to spend the money to discover all about them. That may change. It’s probably money well spent.
More recently, enormous viruses have been discovered that contain up to 2500 genes and are comparatively massive in size. Some are millions of years old and contain a long gene sequence found in every living thing. We don’t know much about these at all. A regular virus is blown up to the size of a tennis ball. By comparison, our body is five miles high. They can’t be seen under regular microscopes and their presence only deduced in 1900 by a researcher studying tobacco diseases.
(Thanks to Bill Bryson’s The Body, from which many of these statistics were claimed.)
I didn’t know about the giant viruses, that is interesting. But why would a virus need 2500 genes? Some free living bacteria have fewer than that.
One fact that I always found interesting that each day around 40% of all the bacteria in the oceans is killed by viruses. Since there are something like 10^30 bacteria in the oceans that is pretty shocking. I wonder when viruses evolved as parasites for single celled life.
Most people would classify viruses as non-living but of course they can reproduce. No one knows why viruses might need more genes than necessary to perpetuate themselves. I have no idea how water viruses affect bacteria. I’m not sure anyone does, and hadn’t heard facts about it. In general, viruses want to perpetuate and not kill their hosts.
In people, HIV triggered a lot of research about how more complex viruses work. But we still know nothing. In the infamous Belly Button project, swabs were taken from a moderate group of umbilici. Hundreds of new microbes were discovered. Only a few were found on everyone. The world of microbiology is one we don’t understand very well at all.
You’re probably right. On the other hand, our level of knowledge is a little deeper than “it is good to eat fermented foods” and “you probably don’t need to take probiotic pills”. But not much.
Excess genes appears to be a common condition of ALL living things. From what science can tell so far, even in complex life - like us - most of the genetic code doesn’t do anything.
There was a recent WaPo headline “Viruses are not alive, that’s why it’s so hard to kill them” (phrasing may not be exact). My reaction to this was “Oh, viruses are undead? That explains a lot.”
Anyway, anywhere there are living things, whether bacteria, plants, animals, whatever, there are going to be viruses that parasitize them. That’s something that’s never going to change.
They may not meet the criteria for life, but they do make proteins that can be targets for pharmaceuticals that stop the viral life cycle.
With the HIV virus, there are several drugs that block various proteins the virus needs to reproduce. The flu drug tamiflu works by blocking proteins the virus needs to escape a host cell.
Some of the proteins that HIV drugs block could also block proteins the coronavirus needs to reproduce. Protease inhibitors that are already FDA approved for HIV are being looked into as treatments for coronavirus.
I’m not sure why antiviral therapy seems to be so far behind antibiotic therapy. I’m guessing because the most virulent viruses respond to vaccines, and for the most part most we don’t have a lot of dangerous viruses that aren’t unvaccinated. But I mean we do have HIV, ebola, coronavirus, the flu, zika, hantavirus, etc. I honestly don’t know, it just seems like a field that should be more advanced. Maybe part of it is the fact that other than the flu and HIV, most of these infections affect the third world and there isn’t much market for R&D for drugs for poor people.
In the case of giant virus genes, about 90% of them have never been seen anywhere else. Excess genes otherwise abound, but most are common to our ancestors.
I definitely did not know that ocean virus-bacteria interactions were so frequent or significant. Of course, I did not know until recently water viruses were so incredibly numerous.
Since so many medical benefits came from microbes (see how penicillin or cyclosporine was developed) it would probably be worth the research money to know much more about them. Especially if we’ll be spending trillions on maintenance.
It definitely feels like we should know a lot more about them.
Living things evolved from non-living things. It isn’t surprising that the boundary between them is small, possibly arbitrary. But living things are often defined to include movement, growth, nutrition, respiration, excretion, reproduction and sensitivity to environmental changes. Other definitions are possible.
Viruses have no means of movement, growth, cannot reproduce without an intermediary, do not breathe, do not eat or excrete. They perhaps have the ability to chemically sense when they are on a possible target and can reproduce in a sense. Most biologists would classify them as non-living. They are inert unless activated.
Because there is no comprehensive, universally-accepted definition of “life.” (And “needing genetic material to reproduce” isn’t comprehensive of any of them.) Myself, I prefer the definition “A self-sustaining chemical system capable of Darwinian evolution.” But that clearly excludes viruses, virusoids, virods, virelles (okay, I made that one up), satellites, and prions.
Nobody is even sure if viruses evolved from cellular life or if cellular life evolved from viruses, some combination of both, or neither.
It’s my understanding that the protease in SARS-2 is different than in HIV, so the HIV treatment drugs weren’t expected to work very well. The same idea might work, but it will require somewhat different drugs.
As far as the life thing, living, species, etc. are just definitions that humans made up. Things existing in nature don’t actually have to abide by those definitions.
The hitch isn’t the “capable of Darwinian evolution” part, it is the “self-sustaining chemical system” part. Viruses (and the other things I mentioned) are helpless inert lumps without access to the machinery inside a cell. All of the evolution via mutation of a virus is done inside of a cell using the cell’s tools (for the most part–some types of viruses have to bring along a tool for converting their genetic material to the proper type of DNA before the cell can work with it–but that still takes place inside the cell.)
(Of course, there are those who argue the opposite–that viruses do reach the level of being life. Fewer would argue the same for virusoids and viroids.)
Think about how many parts of a computer you can strip away and still call it a computer. Take away the monitor? Keyboard? Mouse? Sure, still a computer. Well, a virus is basically a non-bootable Micro SD card and nothing else.
[Internet Pedant Mode]
Micro SD cards contain microcontrollers made with 100Mhz CPUs, and such. Not powerful by today’s standards, but consider that the microcontroller/cpu inside USB-C chargers are often several times more powerful than the football field of computing, the Apollo 11 guidance computer.
I absolutely agree with your analogy, in that a MicroSD card isn’t a PC, but for many definitions of “computer” a MicroSD card, keyboard, mouse, monitor, etc. all will meet the definition on their own.
Trying to be a bit light in this whole depressing forum.