Study Answers and Raises Questions About HIV Virus and Origins

September 16, 2010 11:47 AM

The HIV ancestor virus, SIV, has been around much longer than previously thought. The NY Times notes: "And that assumption in turn complicates a question that has bedeviled AIDS scientists for years: What happened in Africa in the early 20th century that let a mild monkey disease move into humans, mutate to become highly transmissible and then explode into one of history’s great killers, one that has claimed 25 million lives so far?"

The study of monkeys from Bioko, an island off the West African coast, on which six monkey species have developed in isolation since it broke off from the mainland 10,000 years ago was done by Tulane University’s National Primate Research Center. Details of their work by disease and by division of immunology.

Supporting materials of the study printed by Science Magazine here (pdf). The full article is only available for members only.

As a side note: Bioko conservation efforts and more information on Bioko primates.

posted by questionsandanchors (61 comments total)

What happened in Africa in the early 20th century that let a mild monkey disease move into humans...

I'm guessing somebody had some hot monkey sex.
posted by Floydd at 11:57 AM on September 16, 2010

I suspect the virus has jumped into human populations many times. The difference in the 20th century was widespread travel and higher population densities that let a spark turn into a wildfire.
posted by mullingitover at 12:00 PM on September 16, 2010 [9 favorites]

Dr. [Preston] Marx believes the crucial event was the introduction into Africa of millions of inexpensive, mass-produced syringes in the 1950s. Campaigns to wipe out yaws, syphilis, malaria, smallpox and polio all required syringes, and many were reused, often with official approval. Also, traditional healers adopted them for injecting their decoctions and they became a status symbol; one study in Uganda in the 1960s found that 80 percent of families owned one.

Without knowing all the science involved in this latest research, this seems at first blush to be similar in some ways to the theory that Edward Hooper put forward 10 years ago in The River, except that according to his theory, it was the polio vaccine that facilitated crossover and transmission, not the syringes. Hooper was eventually discredited, so I'm wondering if this will revive discussion of his theory in any way.
posted by blucevalo at 12:01 PM on September 16, 2010

Also, video games.
posted by Plutor at 12:01 PM on September 16, 2010

explode into one of history’s great killers, one that has claimed 25 million lives so far?"

I think AIDS needs to be fought with everything we've got. But one of history's great killers? Hardly. The Black Death alone reduced the human population by more than one-quarter in a century. Malaria has killed 3 million a year for years and years.

AIDS is a killer and needs a lot of attention. But it isn't one of history's great killers.
posted by Ironmouth at 12:02 PM on September 16, 2010 [10 favorites]

I'm guessing somebody had some hot monkey sex.

OK, so my guess is that this is a joke. It is far more likely that bloodborne diseases were transferred from primate to human during the butchering process after someone killed a mangabey with SIV or a mountain gorilla with ebola, nicked their finger and got some of the infected blood into their own wound. Comments of the lolafricansmonkeysex sort really aren't helpful.
posted by ChuraChura at 12:17 PM on September 16, 2010 [15 favorites]

You make a convincing argument, Ironmouth. I'm sure if the gay community and most of sub-Saharan Africa could have this explained to them, it would provide some much needed perspective.
posted by [citation needed] at 12:19 PM on September 16, 2010 [1 favorite]

You make a convincing argument, Ironmouth. I'm sure if the gay community and most of sub-Saharan Africa could have this explained to them, it would provide some much needed perspective.

Not being honest gives ammunition to those who would ignore the problem. To win arguments we must be honest brokers of information.
posted by Ironmouth at 12:29 PM on September 16, 2010 [10 favorites]

When, and at what number, then, does AIDS become worthy of that title for you? Seems arbitrary.
posted by mikeh at 12:33 PM on September 16, 2010

AIDS is a killer and needs a lot of attention. But it isn't one of history's great killers.

Consider this: If I killed even, I don't know, ten thousand people, I'd be considered a pretty good killer (note: so far I've only killed about three hundred, and most of them were ninjas, who should really only count for being something like .4 of a person for tallying purposes). AIDS has killed orders of magnitude more people that that, and it isn't even trying. It's killing people as a side effect of its goals. You don't even want to think about what it could do if it were really trying. If that's not enough to earn the title of "great killer", I really don't know what is.
posted by Parasite Unseen at 12:40 PM on September 16, 2010 [7 favorites]

When, and at what number, then, does AIDS become worthy of that title for you? Seems arbitrary.

More of a percentage thing. 250 million, a tragedy, yes, but it isn't 1/4 of the world's population. AIDS would have to kill 1.75 billion to get up there with the Black Death. That's a lot more.

What we need to to is focus on (1) how bad it could be; and (2) how it strikes our very ability to reproduce.

Turning away from the issue of 'greatest ever' etc., I find the article itself fascinating. What about a mutation? Is SIV the same as HIV? Or is it different? One mutation could be what has made this so deadly.

We still have no cure, just medicine that supresses the action of the virus, which still puts people at risk. Knowing what that mutation is might help us attack HIV in better ways.
posted by Ironmouth at 12:41 PM on September 16, 2010 [4 favorites]

Regarding the question of whether AIDS is actually one of history's great killers, that is not actually a quantitative assertion, because "great" does not have a numerical definition. Suppose that we are to compile a list of all causes of human death, within recorded history, ranked by number of deaths caused. This is a bit tricky because lots of people have died without having a accurate record of the cause of death - for example, deaths by cancer were not recognized as such for most of human history, and would just be considered "natural causes" or possibly something like an ague. Smallpox may or may not be #1 on the list but it would be close to the top, at least. Influenza, of various strains, is definitely a major cause of death, possibly even #1 on the list. War is a major cause. WW II alone killed more people (if we include both civilian and military deaths) than AIDS has. We would have such causes as heart disease, cancer, starvation and malnutrition, pretty high on the list. Where is AIDS on the list? I'll bet it is still somewhere in the top 100. Does this make it one of history's great killers? That is a matter of opinion. But certainly, it has caused a lot of trauma in recent decades. As [citation needed] states, certain communities have been hit very hard. It is a socially significant disease, regardless of its exact standing among the list of major causes of death.
posted by grizzled at 12:43 PM on September 16, 2010

ChuraChura: YES. Or was bitten by a monkey they were trying to shoo out of the garden. The hurf-durf-monkey-sex comments aren't helpful.
posted by honeydew at 12:45 PM on September 16, 2010 [1 favorite]

Ironmouth: "AIDS is a killer and needs a lot of attention. But it isn't one of history's great killers."

The terrifying thing about AIDS is that it's a silent killer. If someone contracts malaria, in a week they'll be exhibiting obvious symptoms (in most cases anyway).

If someone gets AIDS, the virus could be dormant for years. Add to that a lack of education or resources and the virus becomes extremely dangerous as the only way to prevent it from spreading is by knowing it's there and then knowing how to take precautions. And, if they don't live in a developed country they are going to die because of it, no buts or maybes.

So, while it's not the 'greatest' killer ever, it's up there with the rest of them thanks to its sneakiness and its death rate in third world countries.
posted by Memo at 12:45 PM on September 16, 2010 [1 favorite]

If that's not enough to earn the title of "great killer", I really don't know what is.

Ironmouth is right. AIDS is bad enough without resorting to false hyperbole. Something can be really terrible without being "one of history's greatest killers". When you're talking about something important like HIV it is even more vital to be accurate and honest, not less important.
posted by Justinian at 12:48 PM on September 16, 2010 [2 favorites]

Even though HIV/AIDS kills a lot fewer people directly than do other diseases, such as malaria, I think it has a disproportionate impact because of how it connects with social marginalization and poverty. It isn't HIV in a vacuum -- it's HIV plus TB, HIV plus malnutrition, HIV plus overcrowded prisons, HIV plus homophobia, HIV plus the war on drugs.

Malaria and other diseases connect with poverty in obvious ways; few other diseases are as strongly connected with social marginalization and all those weird things our societies do to perpetuate and exagerate inequality. There's a bit of a "canary in a coal mine" aspect to it, in terms of how societies have chosen to respond tells us so much about underlying attitudes towards the marginalized. So the impact of a disease isn't measured only in raw numbers killed, and certainly our health care and prevention funding isn't targeted that way.

Having said all of that, I've always thought that informal medical practices have gotten a lot less credit for spreading HIV than has unprotected sex. You don't have to spend much time in poor communities to see uses of needles and other medical paraphernalia that make even the riskiest sex look pretty safe.
posted by Forktine at 12:49 PM on September 16, 2010 [5 favorites]

Well, the big difference is that, in the modern era, we don't expect an epidemic to take out 25% of the population. Mostly because we now know it isn't demons or sin or whatever that causes them. So, our metric for a killer disease has changed. I don't think it's dishonest to call a disease that's killed about two or three times as many people as World War II a "great killer".
posted by maus at 12:50 PM on September 16, 2010

(so, maybe not 'History's Greatest Killer', but very likely 'the 20th Century's Greatest Killer')
posted by maus at 12:51 PM on September 16, 2010

Even though HIV/AIDS kills a lot fewer people directly than do other diseases, such as malaria, I think it has a disproportionate impact because of how it connects with social marginalization and poverty. It isn't HIV in a vacuum -- it's HIV plus TB, HIV plus malnutrition, HIV plus overcrowded prisons, HIV plus homophobia, HIV plus the war on drugs.

This is why it needs a lot of attention right now.
posted by Ironmouth at 12:52 PM on September 16, 2010

What happened in Africa in the early 20th century that let a mild monkey disease move into humans...

I'm guessing somebody had some hot monkey sex.

Thank you for revisiting one of the early, (IMO) blatantly racist jokes about AIDS, Floydd. That "har har dumbshit Africans have sex with apes (subtext: they aren't that different)" story was actually passed around in the early days of AIDS awareness as an urban myth of its origin.
posted by IAmBroom at 12:52 PM on September 16, 2010 [2 favorites]

(so, maybe not 'History's Greatest Killer', but very likely 'the 20th Century's Greatest Killer')

Influenza kicked its ass in 1918. And that was even after people understood the germ theory of disease.

50 million in a single year. 3% of the entire world's population.
posted by Ironmouth at 12:54 PM on September 16, 2010

Where is AIDS on the list? I'll bet it is still somewhere in the top 100.

That's an interesting question. Is being in the top 10 causes of death in the last 20 years enough to put it on the top 100 list of the last 200,000 years? I'm not sure. The human population was hugely lower until very recently so it's quite possible that you're right. But I would also bet that the gulf between number of deaths caused by things like heart attack, cancer, stroke, various causes of infant mortality, violence, etc and "modern" diseases like AIDS is so huge as to make a "top 100" list fairly meaningless. It' be like a "top 100" list of banana varieties consumed historically. The number of Cavendish and Gros Michel bananas eaten would be so much larger than the rest that it'd be a pointless list to make.

I will agree that living in a medically advanced Western nation makes this conversation even possible and that AIDS is a tragic scourge, particularly in places like sub-Saharan Africa.
posted by Justinian at 12:57 PM on September 16, 2010

You make a convincing argument, Ironmouth. I'm sure if the gay community and most of sub-Saharan Africa could have this explained to them, it would provide some much needed perspective.

Seriously? Go f-- off.

Ironmouth was simply pointing out a numerical statistic. Fighting HIV is very much worthy of our attention -- but so are the efforts to fight other diseases that kill lots of people. I don't see why this needs to be an either/or situation.

It is worth noting that HIV/AIDS has effected certain populations more than others, although that doesn't make anybody's "perspective" any more or less valid.

I suppose that you could argue that the Holocaust wasn't a particularly big deal, in light of the fact that the 6-12 million people murdered were only a small percentage of the world population at the time (or even the 75 million total deaths during WWII). However, the fact that it reduced the population of European Jews by two thirds makes it a rather significant event.

To the communities effected by HIV/AIDS, it's a %*#ing big deal (AIDS deaths in New York City in the 90s were roughly equivalent to a 9/11 every 3 months). On a global scale, it's admittedly somewhat less of a big deal (in terms of numbers), although that's no reason to stop fighting it.

There is a sound statistical and scientific argument for fighting the AIDS crisis with every weapon in our arsenal. However, it is similarly true that we should not let our emotional biases cloud our humanitarian and disease-fighting efforts.
posted by schmod at 12:58 PM on September 16, 2010 [1 favorite]

Hey, lookie here! A WHO list of causes of death. The plucky newcomer AIDS has trounced perennial faves Tuberculosis and Malaria, responsible for almost 5% of all deaths worldwide! In the competitive Developing Country bracket, AIDS does even better, and is the single leading cause of death by some estimations.

Regardless of the malleability of these statistics, one thing is clear: HIV is now the world's single most lethal infection. In South Africa, Zimbabwe and Botswana AIDS is now responsible for more than 50% of all deaths. It may not yet be one of history's great killers by your standards, Ironmouth, but give it time. With allies like HIV denialist South African politicians and the Catholic Church, it can't fail.
posted by [citation needed] at 1:00 PM on September 16, 2010 [5 favorites]

Of course, when the apocalypse comes, we're not going to die of AIDS but rather from Cholera.
posted by Memo at 1:01 PM on September 16, 2010

I don't think it's dishonest to call a disease that's killed about two or three times as many people as World War II a "great killer".

Estimates of WWII deaths are difficult because of the great uncertainty about deaths in China and to a lesser extent Russia, but certainly the total number of casualties was at least 60,000,000 and possibly as high as 100,000,000. AIDS deaths are around 25,000,000. Given error bars that puts AIDS deaths at anywhere from 1/2 to 1/4 of WWII deaths.
posted by Justinian at 1:01 PM on September 16, 2010

What has caused the change though? I was looking through this flu thing, and the fact that soldiers stayed in the same place was a big part of why suddenly, it killed so many. 25 million in 25 weeks.

So we have a virus here, which was apparently introduced into the population multiple times and nothing happened. Suddenly, boom! Why does that happen?

Do we have an epidemeologist in the house?
posted by Ironmouth at 1:02 PM on September 16, 2010

HIV is now the world's single most lethal infection. In South Africa, Zimbabwe and Botswana AIDS is now responsible for more than 50% of all deaths. It may not yet be one of history's great killers by your standards, Ironmouth, but give it time. With allies like HIV denialist South African politicians and the Catholic Church, it can't fail.

It spreads other diseases too, by weakening the body's own defenses. It has to be hit hard. Its the future of AIDS that is the spectre that needs to be dealt with.
posted by Ironmouth at 1:04 PM on September 16, 2010

AIDS has possibly been killing humans for a long time - but how would anybody know what was happening prior to say, 1950?
posted by Xoebe at 1:04 PM on September 16, 2010

The full article is only available for members only.

From the paper: "We acknowledge support from NIH grants 1RO1AI27698 and 1RO1AI44596, a Tulane Phase II Enhancement Grant, the ExxonMobil Foundation, and the David and Lucile Packard Foundation"

How very fair it is that research our tax dollars have paid for is hidden behind a lucrative paywall for the publishers.
posted by 7-7 at 1:04 PM on September 16, 2010 [3 favorites]

ChuraChura: YES. Or was bitten by a monkey they were trying to shoo out of the garden. The hurf-durf-monkey-sex comments aren't helpful.

Blood-to-blood transmission through eating and butchering is a far more likely vector, which brings us back to why now, instead of the tens of thousands of years we've been eating monkeys and apes.
posted by Ironmouth at 1:06 PM on September 16, 2010

Regardless of the malleability of these statistics, one thing is clear: HIV is now the world's single most lethal infection.

Um. The chart you link to has AIDS as the second most lethal infection after pneumonia ("respiratory infection"). I guess one could make the argument that since pneumonia could be caused by a number of different pathogens that it doesn't count as one infection but that's kind of pedantic.
posted by Justinian at 1:07 PM on September 16, 2010

AIDS has possibly been killing humans for a long time - but how would anybody know what was happening prior to say, 1950?

In a sense it has never killed anyone directly, which might make it hard to detect in the past. It just reduces the ability of the body to fight regular infection. So we may have had it for tens of thousands of years.
posted by Ironmouth at 1:08 PM on September 16, 2010 [2 favorites]

Is AIDS a great killer?

To paraphrase a great thinker: "Killing doesn't make one great..."
posted by coolguymichael at 1:18 PM on September 16, 2010

Dr, Mary's monkey virus.
posted by hortense at 1:33 PM on September 16, 2010

More of a percentage thing. 250 million, a tragedy, yes, but it isn't 1/4 of the world's population. AIDS would have to kill 1.75 billion to get up there with the Black Death. That's a lot more.

What I'd love to see -- for purely academic reasons -- is two charts:

1: A chart showing human deaths, by number, for the top twenty killers (including diseases, but also wars, genocide, malnutrition, and so on).

2: A chart showing human deaths, by percentage of the total population, for the same thing.

It's reasonable to say that something is a low number by percentage, but a high number by total deaths, and vice versa. I would argue that the percentage number is more statistically useful for research, but the total number is a better reflection of impact on the human condition.

Consider: if you have one child and your neighbor has eight, and you each lose a child to an illness or other tragedy, a disinterested third party might claim you were worse off than your neighbor because your only child was taken -- but I doubt you and your neighbor would feel a level of loss that's substantially different.
posted by davejay at 1:40 PM on September 16, 2010

It is far more likely that bloodborne diseases were transferred from primate to human during the butchering process after someone killed a mangabey with SIV or a mountain gorilla with ebola, nicked their finger and got some of the infected blood into their own wound.

There have also been theories that transmission to humans may have occurred due to a monkey biting a human and/or humans consuming infected monkey meat (e.g. smoked monkey is a common food item in Rawanda).
posted by ericb at 1:46 PM on September 16, 2010

I suspect the virus has jumped into human populations many times.

It is far more likely that bloodborne diseases were transferred from primate to human during the butchering process...

Exactly, as stated in the FPP's linked article:

"In a discovery that sheds new light on the history of AIDS, scientists have found evidence that the ancestor to the virus that causes the disease has been in monkeys and apes for at least 32,000 years — not just a few hundred years, as had been previously thought.

That means humans have presumably been exposed many times to S.I.V., the simian immunodeficiency virus, since people have been hunting monkeys for millennia, risking infection every time they butcher one for food."

posted by ericb at 1:50 PM on September 16, 2010

The difference in the 20th century was widespread travel and higher population densities that let a spark turn into a wildfire.

Exactly.

And one disputed and debated initial spark may have been Air Canada flight attendant Gaëtan Dugas (aka Patient Zero), as profiled in Randy Shilts's book 'And the Band Played On.'

Some believe that HIV probably moved from Africa to Haiti and then entered the United States around 1969, probably through a single immigrant.
posted by ericb at 1:57 PM on September 16, 2010

I guess one could make the argument that since pneumonia could be caused by a number of different pathogens that it doesn't count as one infection but that's kind of pedantic.

Considering pneumonia can be caused by any number of viruses, bacteria, fungi or parasites, I don't think it's a pedantic distinction at all, especially when you are deciding where money for fighting infectious disease should go.
posted by [citation needed] at 2:10 PM on September 16, 2010 [1 favorite]

...this seems at first blush to be similar in some ways to the theory that Edward Hooper put forward 10 years ago in The River...

And Hooper first learned of the OPV AIDS hypothesis when he read a 1992 article in Rolling Stone magazine by Tom Curtis. Curtis described a theory advanced by Louis Pascal that HIV was inadvertently caused in the late 1950s in the Belgian Congo by Hilary Koprowski*'s testing of an oral polio vaccine (OPV) on human subjects.

* -- Hilary Koprowski sued Rolling Stone and Tom Curtis for defamation.

"The editors of Rolling Stone wish to clarify that they never intended to suggest in the article that there is any scientific proof, nor do they know of any scientific proof, that Dr. Koprowski, an illustrious scientist, was in fact responsible for introducing AIDS to the human population or that he is the father of AIDS."

Rolling Stone was ordered to pay $1.00 in damages while incurring around $500,000 in legal fees for its own defense.
posted by ericb at 2:10 PM on September 16, 2010

transmission to humans may have occurred due to a monkey biting a human

Yeah, it could have been for a lot of reasons. Monkey sex is so immature! Toby could have just been walking along, minding his own business. It was hot, and it's Africa, so Toby doesn't wear pants or shorts—far too hot for that. Anyway, he's walking along, naked, and he has to pass by the monkey lake. Except he sees some beautiful young ladies are bathing in the monkey lake, so he watches them from afar. As he starts to walk away he slips on one of the banana peels the monkeys have been leaving around; he tried to regain his balance, but the monkeys all start laughing at him, this naked dude with a boner all flailing about like a flailing madman. Anyway, he falls on a monkey accidentally and penetrates the monkey accidentally and gets AIDS because the monkey that he accidentally fell on had AIDS.

and/or humans consuming infected monkey meat

…or that.
posted by Civil_Disobedient at 2:23 PM on September 16, 2010

Also worth considering is how many of those pneumonia deaths are just a proximate cause of death where there is a more distal ultimate cause or strong contributing factors, such as very advanced age, malnutrition or chronic illness. I'm having trouble finding a source, but I believe pneumonia is the most common proximate cause of death for AIDS victims. AIDS is also largely responsible for the resurgence of TB in Africa, and AIDS/TB co-infection is an especially lethal and pernicious problem that is only going to get worse in the short term.

I will unapologetically state that stopping the spread of HIV is now the world's single most important public health challenge.
posted by [citation needed] at 2:25 PM on September 16, 2010 [1 favorite]

AIDS has possibly been killing humans for a long time - but how would anybody know what was happening prior to say, 1950?

"Four of the earliest known instances of HIV infection are as follows:

1. A plasma sample taken in 1959 from an adult male living in what is now the Democratic Republic of the Congo.

2. A lymph node sample taken in 1960 from an adult female, also from the Democratic Republic of the Congo.

3. HIV found in tissue samples from an American teenager who died in St. Louis in 1969.

4. HIV found in tissue samples from a Norwegian sailor who died around 1976."*

And, maybe earlier:

First HIV case 'can be traced to 1930s'.

posted by ericb at 2:27 PM on September 16, 2010 [3 favorites]

Given error bars that puts AIDS deaths at anywhere from 1/2 to 1/4 of WWII deaths.

Well, give HIV some time. After all, no one has died in WWII since the end of WWII. People can live a long time with HIV - long enough to infect the babies they carry, long enough to infect the people they have sex with or share needles with. There's still a lot of dying to happen, and I'm sure it will triumph over WWII deaths at some point in the not-that-distant future.
posted by rtha at 2:47 PM on September 16, 2010

People can live a long time with HIV...

Yep.

HIV's latency stage (i.e. its ability to "hide" in a latent form in resting CD4-T cells) "can vary between two weeks and 20 years."*
posted by ericb at 2:52 PM on September 16, 2010

I've always been interested in causes of death as stealing life.

On a long enough timeline everyone's survival rate drops to zero.

Some causes of death like automobile accidents and HIV are worse because they take the young. If nothing else kills you cancer or heart disease are pretty durn likely, but they almost always come after many years of life.

Maybe I should fire up R tonight and see what I can uncover.
posted by poe at 3:00 PM on September 16, 2010

I'm guessing somebody had some hot monkey sex.

OK, so my guess is that this is a joke. It is far more likely that bloodborne diseases were transferred from primate to human during the butchering process after someone killed a mangabey with SIV or a mountain gorilla with ebola, nicked their finger and got some of the infected blood into their own wound. Comments of the lolafricansmonkeysex sort really aren't helpful.

Whether it's controversial or not, people in all parts of the world have had sex with animals.... Has anyone thought about the possibility?
posted by Not Supplied at 3:26 PM on September 16, 2010

wiki:

The Kinsey reports controversially rated the percentage of people who had sexual interaction with animals at some point in their lives as 8% for men and 3.6% for women, and claimed it was 40–50 percent in people living near farms,[7] but some later writers dispute the figures, because the study lacked a random sample, and because the prison population was included, causing sampling bias. Martin Duberman has written that it is difficult to get a random sample in sexual research, and that even when Paul Gebhard, Kinsey's research successor, removed prison samples from the figures, he found the figures were not significantly changed.[8]
posted by Not Supplied at 3:28 PM on September 16, 2010 [1 favorite]

Monkey sex fascinates the puerile mind. Were that said minds would stfu about it. The conversation has been informative and adult. Go pollute another thread.
posted by five fresh fish at 3:43 PM on September 16, 2010 [2 favorites]

Has anyone thought about the possibility?

EARLIER IN THIS THREAD, IN FACT!
posted by mek at 4:05 PM on September 16, 2010

Whether it's controversial or not, people in all parts of the world have had sex with animals.... Has anyone thought about the possibility?

Its a highly unlikely vector. Far more likely that actual blood contact did it. Way easier.
posted by Ironmouth at 4:18 PM on September 16, 2010

Whether it's controversial or not, people in all parts of the world have had sex with animals.... Has anyone thought about the possibility?

Considering a monkey has the strength to rip a human being to shreds, it might take at least two or three dates just to get to first base.
posted by Blazecock Pileon at 4:41 PM on September 16, 2010 [3 favorites]

Even cute little spider monkeys?
posted by kaibutsu at 5:37 PM on September 16, 2010

Do we have an epidemeologist in the house?

Well, there's a pickup line I never expected.

I'm doing my PhD in epi on HIV treatment among individuals who use injection drugs; I did my undergrad on molecular evolution. I'm not totally up on the literature any longer, but I'm not sure anyone has surpassed Bette Korber et al.'s study timing the ancestor of the HIV-1 pandemic strain published in Science in 2000.

Korber et al. sought to date when HIV-1 jumped species by estimating the age of the oldest common ancestor to all known HIV-1 samples. This is a common procedure used to estimate population structures or relationships between species (in the near term, evolutionarily-speaking) and evolutionary histories (in the longer term.) It rests on the idea that if you can find a gene common to two organisms and you know the rate at which DNA in that gene changes, you can estimate the time at which those two species diverged.

In practice, things get very complex very quickly, and Korber et al.'s methodology -- using parallel computers to align 66 HIV-1 samples, create a consensus sequence, and estimate the most likely evolutionary phylogeny using maximum likelihood -- was suitably rigorous. They estimate the date of the oldest common ancestor was 1930 (95% CI: 1895 - 1965).

Beyond the dating, they don't go into much detail in the Discussion about resulting pandemic spread of the pathogen. However, they do point out: "If the HIV-1 M group [the major pandemic clade] did enter the human population and then diversify, for a 25- to 60- year period before the onset of the pandemic and the first retrospective clinical documentation of AIDS in Africa in the 1970s, the virus must have gone undetected. Given the difficulty in retrospectively diagnosing the myriad of symptoms that make up AIDS, particularly in a rural African setting, it is feasible that small numbers of HIV-1 infections could have gone unrecognized. Lack of evidence for early HIV-1 in- fections is, in this context, uninformative."

Korber et al points to Chitnis et al.'s review of some of the environmental, social and structural factors that may have facilitated sustained viral transmission in Africa and, eventually, pandemic spread abroad. Briefly, those can be broken down into:

1. Increased consumption of bushmeat due to colonial labour practices (plantation workers no longer had the time/energy to farm, leading to consumption of bushmeat), fleeing from same and increased availability of firearms to acquire bushmeat;
2. Rapid urbanisation, causing a vastly increased number of interactions between infected and susceptible host;
3. Social turmoil of urbanisation, forced labour/forced resettlement and war, leading to increased sexual contacts;
4. Parenteral transmission through vaccination campaigns (i.e., six syringes were used to screen and treat 90,000 people for sleeping sickness in 1917-1919);
5. Adaptation of HIV-1 variants selected for better human to human transmission due to arm-to-arm inoculation campaigns against smallpox

Chitnis et al. suggest that the roots of HIV-1 pandemic spread are in colonial French Equatorial Africa between 1890 and 1930. This is consistent with Korber's calculations, made later, as well as, more generally, the observations of many epidemiologists, public health practitioners and people living with HIV/AIDS, like Dr. Paul Farmer, that HIV moves through the cracks in human societies, targetting those made vulnerable through social, cultural and economic exclusion.
posted by docgonzo at 6:03 PM on September 16, 2010 [18 favorites]

It's possible SIV has jumped a bunch of times in history, but it was probably like most of the other animal-human jumps where each time it is different. This most recent jump had the unfortunate circumstance of high virulence and long incubation times to make it "stick". From the virus's perspective, it is as close to virus perfection as you can get, I think.

And then yes, the highly mobile world that it jumped into helped a lot too. A world of relatively greater promiscuity and drug use didn't help any either. (Not judging.)
posted by gjc at 6:10 PM on September 16, 2010

Given error bars that puts AIDS deaths at anywhere from 1/2 to 1/4 of WWII deaths.

Well, give HIV some time. After all, no one has died in WWII since the end of WWII.

"In WWII", no; you're technically correct, rtha. However, WWII deaths continued for decades. Q.v. "Hiroshima and Nagasaki, victims from".
posted by IAmBroom at 6:20 PM on September 16, 2010

docgonzo:the roots of HIV-1 pandemic spread are in colonial French Equatorial Africa between 1890 and 1930."

It's illuminating that the NYT, and many of the posters here, spend so much time debating the (discredited) cultural flashpoints of the late 20th century (vaccination, promiscuity, drugs, sexuality) as etiologies when, as pointed out above, HIV's cladistics have clearly illustrated for more than a decade that our current HIV pandemic is blowback from colonialism (one of the major cultural flashpoints of the late 19th century). It's yet another Late Victorian Holocaust - this one just took a little longer to get going.
posted by meehawl at 8:45 PM on September 16, 2010

Is AIDS a great killer?

To paraphrase a great thinker: "Killing doesn't make one great..."


To paraphrase a great killer: "Thinking doesn't make one great..."
posted by schmod at 8:53 PM on September 16, 2010

Listening to one of the 20th century wrap-up shows on NPR, I heard a couple of demographers claim the toll of wars in the 20th was about 300 million, and the toll of smallpox was at least 500 million.
posted by jamjam at 12:49 AM on September 17, 2010

How very fair it is that research our tax dollars have paid for is hidden behind a lucrative paywall for the publishers.

Complain to your Congressman. This should be changed.
posted by grouse at 9:25 AM on September 17, 2010