HIV evolving 'into milder form'

http://m.bbc.co.uk/news/health-30254697

by GotAnyMegadeth • 12 years ago

101 69 12 years ago

m.bbc.co.uk

guard-of-terra• 12 years ago

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

ars4• 12 years ago

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.

couradical• 12 years ago

Sure it can - think of smallpox: the first smallpox "vaccine" was actually inoculation with cowpox - a similar, but less virulent virus. The provoked immune response rendered a smallpox infection less lethal, and provided a measure of protection.

- http://en.wikipedia.org/wiki/Smallpox_vaccine

SideburnsOfDoom• 12 years ago

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

Beltiras• 12 years ago

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

Dylan16807• 12 years ago

Don't just assume that. (Even if you happen to be right in this case.)

streptomycin• 12 years ago

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.

cryoshon• 12 years ago

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."

ars4• 12 years ago

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).

shittyanalogy2• 12 years ago

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.

GotAnyMegadeth• 12 years ago

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-...

billpg2• 12 years ago

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.

zecg• 12 years ago

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

hazz• 12 years ago

90-95% of adults had it at some point. Most people develop immunity to it and so it doesn't survive in them. I'd say the most successful virus in humans would be the common cold, given how frequently we seem to get it, although it's more of a massive family of virii.

teddyh• 12 years ago

Like this?

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

MiddleEndian• 12 years ago

Made me think of this one: http://www.smbc-comics.com/?id=3091

kingkawn2• 12 years ago

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

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

waps• 12 years ago

While this is a communication pattern, it is still governed by evolution. Therefore, as a host, you get one vote.

Either you live at least long enough to spread the virus a little bit, and you vote that what the virus is doing is good, or you die before spreading, and you vote what the virus is doing is bad.

Let's get voting !

bayesianhorse2• 12 years ago

"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.

dredmorbius2• 12 years ago

It's quite avoidable. The viral load in various ecosystems can be tremendous, and many are generally benign. Even the non-benign generally don't kill their hosts.

An interesting tidbit from xkcd's "What If" series: individual cell mortality from viruses in the oceans is about 20% per day.

http://what-if.xkcd.com/80/

http://www.reddit.com/r/dredmorbius/comments/1vyanj/viral_so...

Jared Diamond has offered related observations on pathogens and parasites in tropical vs. temperate climates. It strikes me that an ecosystem in which there are periodic resets (e.g., killing winter frosts, or long summer droughts) offer a more amenable set of living conditions to those species not affected by those resets, whether by adaptation or technology.

learnstats22• 12 years ago

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.

egeozcan• 12 years ago

If killing you means that the pathogen can spread more rapidly, it will evolve to do so. I don't see the HIV virus gaining anything by killing the host as it depends mostly on sexual intercourse to spread. Correct me if I'm wrong, but, Ebola would have been a better example in this case, I suppose.

shittyanalogy2• 12 years ago

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

smorrow• 12 years ago

The selfish DNA.

cJ0th• 12 years ago

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

TeMPOraL3• 12 years ago

No, that's just evolution - plain, simple and extremely dumb. Viruses don't really "want" anything, they are just biomolecular machines that run around replicating themselves and screwing things up; some manage to copy themselves, some don't - and this way, generation after generation, you're left with those viruses that are good at copying themselves in the environment they're in. Evolution is a statistical phenomenon.

snowwrestler4• 12 years ago

Obviously viruses are not intelligent and they don't "want" to reproduce.

However, they do reproduce, just like pretty much every other form of life. The question of why life does that is closely related to the question of what life is and how it came to exist. Those are deep questions and we don't really have a clue as to the answer right now. There's certainly nothing in the fundamental physical laws of the universe, as we understand them today, that seems to indicate or require the existence of life.

snowwrestler4• 12 years ago

Our ancestors have successfully concluded such negotiations numerous times:

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

Houshalter• 12 years ago

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.

abandonliberty• 12 years ago

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

thanatosmin• 12 years ago

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).

nsajko• 12 years ago

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• 12 years ago

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

ruairinewman• 12 years ago

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?

hnnewguy• 12 years ago

Why do people downvote questions?

jowiar• 12 years ago

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.

ars4• 12 years ago

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.)

kornakiewicz• 12 years ago

Good guy HIV.

fenomas• 12 years ago

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

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

astralship• 12 years ago

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

pistle• 12 years ago

"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.

BrainInAJar• 12 years ago

"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.

HIV evolving 'into milder form'

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