HIV evolving 'into milder form'

[thanatosmin]

Reading the original paper, they compare Botswana and S Africa and find a correlation between seroprevalence and viral load. There is not good evidence to suggest this is causative however--this may be, for example, that as you get to higher frequencies of cases differently aged people are more likely to be infected and show different viral loads. A direct causal link between these two factors doesn't make a huge amount of sense, because (AFAIK) HIV is thought to sample all viral sequences within each host (so population-level selection should represent individual-level variation).

[ars]

That's pretty typical for parasites (which include viruses).

Killing your host is never a good idea, the best parasites cause minimal disruption to their host.

All animals and humans are infected with countless parasites, but you never notice. For example https://en.wikipedia.org/wiki/Face_mite (don't scratch).

[GotAnyMegadeth]

Sometimes if the parasite moves from host to host as part of it's life cycle, and this can include aiding the death of one host. An example of this is a parasite that causes frogs to grow extra legs so that they are easier to catch for birds. The parasite then transfers to the bird, where it can lay it's eggs.

http://phenomena.nationalgeographic.com/2013/02/13/a-flurry-...

[shittyanalogy]

Parasites can have multiple host species, some in which they are benign and some in which they are deadly. Malaria has been killing humans for thousands of years. Also for example, HIV.

[nsajko]

http://www.davidbrin.com/givingplague.html A very nice story of Brin based on the notion of a process of infectious agents "watering down" over time.

[chadgeidel]

Thank you! I was just going to ask for that story!

[BrainInAJar]

"In theory, if we were to let HIV run its course then we would see a human population emerge that was more resistant to the virus than we collectively are today - HIV infection would eventually become almost harmless."

Because millions (or billions) of people would die, leaving only those with resistance.

[pistle]

> "Twenty years ago the time to Aids was 10 years, but in the last 10 years in Botswana that might have increased to 12.5 years, a sort of incremental change, but in the big picture that is a rapid change."

20 years ago, the ARV's and mixes weren't what they were 10 years ago and awareness + access to therapy also changed. Therapy initiation guidelines changed - which would directly impact time to AIDS.

Throw that statement away in relation to the meaning of the study results - except if this statement is there, it raises a concern about bias or mistakes in the study due to an insufficiently rigorous handling of the data and contexts/meaning.

[guard-of-terra]

I wonder if infecting a person with AIDS with milder form of HIV will make them better.

[SideburnsOfDoom]

> wonder if infecting a person with AIDS with milder form of HIV will make them better

Basically, no. Based on current experience it seems that it would not improve matters and may make them worse.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1169464/

http://www.rense.com/general8/multiple.htm

http://i-base.info/qa/2881

[cryoshon]

No, not make them better, but there is an interesting story here which I heard when I attended a lecture at my job researching HIV.

HIV-1 is the "HIV" we all know and fear. While HIV-1 was derived/evolved from SIV (simian immunodeficiency virus), it's actually not as similar to SIV as HIV-2, another strain.

HIV-2 is far less dangerous and transmissible in comparison to HIV-1, and doesn't exist in large quantities outside of sub-Saharan Africa. Critically, there is some new research which shows that infection with HIV-2 first provides a substantial amount of protection against later infection by HIV-1. People who were infected with HIV-2 before being infected with HIV-1 had lower viral loads and slowed disease progression in comparison to people who were infected with HIV-1 alone.

This lead the researcher giving the talk to state the extremely stunning (yet perhaps true) fact: "HIV-2 is the best vaccine against HIV-1 that we have."

[ars]

That would imply that HIV viruses compete with each other, and this competition is able to suppress each other.

This is typical with bacteria, but I don't think it happens with viruses.

[streptomycin]

You are not the first to wonder that! Back in the early 90s some scientists actually tried it on people with severe AIDS http://www.rci.rutgers.edu/~piecze/Lancet.PDF - some seemingly improved, but the trial was too small and preliminary to be conclusive. When they published those results, there was a huge backlash about ethical concerns and the research got shut down.

I took a class taught by Dr. Pieczenik about 5 years ago and he still believed this idea would work if it was allowed to proceed.

[Beltiras]

HIV rewrites how the immune system works. Doing it again more mildly will not improve the situation.

[ruairinewman]

Surely this process means that HIV is just as capable of evolving into something even more lethal over time, given the right environment? Given the relatively closed environment of a country like North Korea (for example) where diversity is restricted, its evolutionary path may take a different route than that observed by the University of Oxford research team?

[jowiar]

Can random mutations make HIV more lethal? Sure. The argument here is that lethality makes HIV "less fit" from an evolutionary standpoint, which makes sense, as, given the means of transmission, killing the host isn't a particularly useful thing for the virus to do.

[ars]

> Surely this process means that HIV is just as capable of evolving into something even more lethal over time, given the right environment?

It's unlikely. HIV doesn't "want" to kill the host because that also kills the HIV, so it's the opposite of what it wants.

You would need an environment that favored killing the host over keeping it alive, and considering how HIV is transmitted that is unlikely. (Unlike Ebola where it can happen because Ebola is best transmitted from a corpse.)

[hnnewguy]

Why do people downvote questions?

[fenomas]

As is so often the case, William Gibson came pretty close to predicting this:

http://everything2.com/title/J.D.+Shapely

[astralship]

strikes me that human immune systems are working collaboratively in the case of HIV

[billpg]

What viruses "want" is to reproduce. Killing you is an unfortunate unplanned side effect.

If only we could negotiate and agree to allow them to reproduce and not kill us, we'd all get along much better.

[Houshalter]

It's like the foxes that over-populate, eat all the rabbits and then all die. The foxes would be better not to reproduce past the limits of their environment, but each individual fox passes on more of it's genes if it doesn't restrain it's own breeding. And so those genes propagate to the detriment of the community.

You need very strong group selection to restrain breeding, and this becomes less and less likely as the population size increases (so each individual has less and less affect.) See The Tradgedy of Group Selectionism: http://lesswrong.com/lw/kw/the_tragedy_of_group_selectionism...

Even when organisms are selectively breed by scientists with group selection to limit their population size, they often just become cannibalistic rather than restrain their own reproduction. Killing someone else's kids is better than killing your own.

Essentially the same thing happens with viruses, where over reproduction means killing all the hosts cells.

[teddyh]

Like this?

http://www.smbc-comics.com/?id=3254#comic

[zecg]

Epstein-Barr virus is close to that ideal, 90-95% of adults have it. Unfortunately, it's connected with cancers: http://en.wikipedia.org/wiki/Epstein%E2%80%93Barr_virus

[bayesianhorse]

"Unintended" side-effect yes. But not really avoidable. The very nature of viruses means destruction, competition for resources with other physiological processes in the host, and they only have a limited capacity to tune their reproduction for optimal transmission. Too little reproduction (and in the wrong places) means too little transmission, too much reproduction means too much damage and thus also less transmission.

[learnstats2]

This negotiation is rather weak since it doesn't recognise the passage of time. Once the viruses have reproduced to their satisfaction, they can renege on the deal when humans have a weaker negotiating position.

That is to say, "Don't negotiate with terrorists."

Fortunately the human/mammalian immune system does not typically permit this kind of deal. With a few exceptions: including HIV.

[kingkawn]

http://www.hhmi.org/research/cell-cell-communication-bacteri...

this work is being done with bacteria, not sure it is possible with viruses though.

[cJ0th]

That's an interesting thought. It's like they posses "artificial intelligence", i.e. they behave like the famous paper clip maximizer.

[abandonliberty]

8% of our genome may be viruses that decided to live with us: http://en.wikipedia.org/wiki/Endogenous_retrovirus?#Human_en...

[snowwrestler]

Our ancestors have successfully concluded such negotiations numerous times:

http://www.bbc.com/news/science-environment-17809503

[shittyanalogy]

I think the problem is DNA. If we could get rid of it we'd be better off.

[kornakiewicz]

Good guy HIV.