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> There is, though. The fitness of a virus is reflected in its ability to reproduce and spread. Yes, in naturally occurring viii who's development is controlle

> There is, though. The fitness of a virus is reflected in its ability to reproduce and spread. Yes, in naturally occurring viii who's development is controlled by natural selection. However there is no absolute genetic impediment to having a virus that is both easily spread (contagious with a medium length incubation time), and deadly (kills host immediately after incubation). Human beings could engineer that virus in the same way we engineered mice that glow in the dark.

jballanc 15y ago
Believing that laboratory-made organisms somehow obey different laws than nature-made organisms is exactly the sort of hubris I was alluding to. There absolutely is a genetic impediment to a virus that is both easily spread and deadly. Biological organisms are highly complex, non-linear, stochastic systems. You can resist malaria, but you'll get sickle cell disease. You might suffer from high prevalence of Cystic Fibrosis, but your population can better resist cholera. Biological variables are, essentially, never independent. This is why systems biology is such a difficult area to study. Oh, and those mice that glow in the dark might look cool in the lab, but they'd be the first to get eaten in the wild. There's a reason mice don't naturally glow in the dark...
- fhars 15y ago
  Of course they don't obey differntet laws and a virus that does both spread fast and kills most of the infected will die out. Because it extinguishes enough of its host population so it can no longer spread. That is sort of the point in this discussion. If it affects just a small village or half a country or more depends on the incubation period.
- learc83 15y ago
  I'd say it's exactly like antibiotic resistant bacteria, in the presence of antibiotics they can outcompete the normal strains. However, in the wild given no antibiotics the non-antibiotic strains will outcompete them.
Retric 15y ago
You can build a virus that does X, but when you send it into the wild it will vary quickly go though 10,000+ generations of natural selection outside the laboratory. It's easy to forget that every new infection start's with a tiny percentage of the host's infection which then needs to replicate a lot before that host can infect someone else. More importantly, you can limit your infection from anything by simply limiting contact. The old "shut down everything" which can contain even a highly infectious virus that's hit a huge chunk of the population aka 5+%. This might not prevent infection but it slows down the spread enough that evolutionary pressure is going to start to push up incubation periods etc.

jballanc 15y ago

Believing that laboratory-made organisms somehow obey different laws than nature-made organisms is exactly the sort of hubris I was alluding to. There absolutely is a genetic impediment to a virus that is both easily spread and deadly. Biological organisms are highly complex, non-linear, stochastic systems. You can resist malaria, but you'll get sickle cell disease. You might suffer from high prevalence of Cystic Fibrosis, but your population can better resist cholera. Biological variables are, essentially, never independent. This is why systems biology is such a difficult area to study. Oh, and those mice that glow in the dark might look cool in the lab, but they'd be the first to get eaten in the wild. There's a reason mice don't naturally glow in the dark...

fhars 15y ago
Of course they don't obey differntet laws and a virus that does both spread fast and kills most of the infected will die out. Because it extinguishes enough of its host population so it can no longer spread. That is sort of the point in this discussion. If it affects just a small village or half a country or more depends on the incubation period.
learc83 15y ago
I'd say it's exactly like antibiotic resistant bacteria, in the presence of antibiotics they can outcompete the normal strains. However, in the wild given no antibiotics the non-antibiotic strains will outcompete them.

Retric 15y ago

You can build a virus that does X, but when you send it into the wild it will vary quickly go though 10,000+ generations of natural selection outside the laboratory. It's easy to forget that every new infection start's with a tiny percentage of the host's infection which then needs to replicate a lot before that host can infect someone else. More importantly, you can limit your infection from anything by simply limiting contact. The old "shut down everything" which can contain even a highly infectious virus that's hit a huge chunk of the population aka 5+%. This might not prevent infection but it slows down the spread enough that evolutionary pressure is going to start to push up incubation periods etc.