Calling all virologists

There exists viruses that develop very slowly (called lentiviruses). A example is HIV which causes AIDS.

-cb

I'm sure you could imagine a compound that would take a long time to dissolve and release a virus, but how would you introduce it? If you introduced it orally, how could you keep it from passing through the digestive tract and out? It would have to be absorbed to get into the body...thus broken down. I suppose you could aerosolize it and have it inhaled. That may work, but slow acting toxins might be safer - less contagious - and more easily obtainable.

You genetically engineer a virus and inject it. You leave the envelope -- the outer layer of the virus -- and modify its contents. I suppose you could have a brilliant geneticists who modifies your viral proteins and invents a way to make the virus dormant in the cell. In real life, though, even if you want to go with a lentivirus, you can't control the dormant phase. It highly depends on the host and a myriad different conditions. BUT, if you want to be realistic, you can give the host drugs that will control the virus (keeping it dormant) and then the minute you stop the drug -- BAM -- viral infection. That's the reason why drug holidays are so bad.

It's complicated to keep a large number of hosts drugged. I get that. It's not complicated to get a large number of hosts to submit to injections? Not everybody is as trusting as Barry Bonds in what they get injected with...unless maybe somebody doctors a batch of flu vaccine...interesting.

Good luck.

sneakysnail said:

shhhht!

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Sorry...carry on.

Two ideas:

First, slightly simpler, but more problematic, perhaps, for the story line: instead of removal of a drug that keeps it dormant, you could have your brilliant geneticist engineer in some sort of trigger. Anything, really, that could get into the blood stream and bind to receptors your virus sticks on the infected cells, which then trigger the virus to move into the next stage. Of course, this would then have to be delivered en masse (tampered water supply?)

The other idea is self-contained: your geneticist could engineer in some kind of counter for cell division, and have a trigger based on increasing concentrations of that. I once saw a model for an idea about this (the counter, not the nefarious part!), but it had some holes--like in reality the thing would probably count an indeterminate number of times each division, instead of just once. Although, I suppose it couldn't be too much more than 5-10 times or so, so if you were willing for some variation in trigger times, that isn't too far fetched. I'm not sure what cells you'd want to infect for this -- it would have to be something that divides at some regularly expected intervals, and that goes beyond my expertise. But I'm sure somebody knows that. If you want to go with something like this, you could use a quorum sensing circuit to respond to the increasing concentration -- these are feedback loops that trigger a self-sustaining behaviour once a certain concentration of the quorum signal is reached.

Hmm. You might be able to do the whole thing with quorum sensing -- just have your nasty emit some small signal that triggers a quorum sensing circuit, and as the number of infected cells increases, eventually there will be enough signal to have it move into phase two. This is how many virulent bacteria work -- they only express virulence factors when their quorum circuits are triggered by high concentrations of signal, so only go virulent when in large numbers.

Packing all this into a tiny viral genome could be tough, but presumably your brilliant geneticist can figure that out. Or, if it fits with the story to have a whole bacteria being the infective agent, you wouldn't have to worry about picking an infective target and could engineer in all sorts of bells and whistles...

sneakysnail said:

ArdenBird, Thank you for the thoughts.

So here is how I wrote it.

My brilliant geneticist , is top man in his field. He has spent several years engineering a virus that once released in the hosts body, boom! your dead. There is of course fever and it is hemorrhagic. Virus have a protein coat that protects the genes; and in some cases an envelope of lipids that surrounds the protein coat when they are outside a cell. He is so brilliant he creates the envelope of lipids to slowly dissolve over time. It effects children and very athletic people first, (They have a quicker metabolism was my thought) But, eventually, anyone injected with said virus ...dead. The pathogenicity is huge.

Just trying to keep it real. I hope the kids getting it first isn't to hokey.
How does that sound. Feasible?

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I'm not a virologist, but I am a biochemist, and I'd buy this explanation. Of course there is a little handwaiving, but there always is going to be some when you are dealing with something that has never been done before. Just don't over-explain the science and you'll be fine.

Good luck with this.

Yeah, with appropriate vagueness, I could probably buy something along those lines. Things to think about (although not necessarily explain) is that the membrane (lipid envelope) around viruses is generally "stolen" from the host cell. The virus can make (get the cell to make...) proteins that get stuck into it, and then the internal protein shell buds from the cell, pushing out and popping off a bit of the cell membrane along with the proteins it made inside the membrane. So, to make a particularly unstable envelope, the virus would either need to have it crammed full of stuff -- I know it could stick proteins in there, but maybe it could get carbohydrates and who knows what else? -- so that the lipids are not particularly stuck well together, or your evil genius could perhaps grow his batch of viruses up in a set of hosts with inherently unstable membranes in the first place.

Or maybe he could coat them with the lipids in a test tube or something, and the "normal" phase of the virus is just a naked protein coat that is infectious. (Because otherwise then I start to wonder how the infection can move quickly if each time the virus replicates it has to wait for its lipid coat to dissolve.)

Hope that is some help

sneakysnail said:

Lets say you encapsulated a deadly microorganism in a strong protein that would would take a while to break down in the human body. Say a month or two. Then bam!

I know there have been some hormones that work that way. A pellet placed under the skin and it slowly dissolves. Couldn't you do that with something microscopic, or would that be horribly unrealistic?

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The problem will be keeping the bacteria alive. If you had spores, perhaps of anthrax or tetanus, and put them into the same material that is used for dissolving sutures, it could work.

Some stable viruses would be easier because they can be crystallized and then encapsulated.

Actually, you don't need to do much to a virus. Some can be dormant for years. With HIV-1, when patients take a drug holiday, you see quasi-species re-emerge that had been observed years earlier.