Gregory Cochran writes in 2012 Edge question series on "What is your favorite deep, elegant, or beautiful explanation?"
Germs Cause Disease
The germ theory of disease has been very successful, particularly if you care about practical payoffs, like staying alive. It explains how disease can rapidly spread to large numbers of people (exponential growth), why there are so many different diseases (distinct pathogen species), and why some kind of contact (sometimes indirect) is required for disease transmission.
In modern language, most disease syndromes turn out to be caused by tiny self-replicating machines whose genetic interests are not closely aligned with ours.
In fact, germ theory has been so successful that it almost seems uninteresting. ...
A huge amount of money has been devoted to searching for the genetic causes of slow-acting diseases because with the development of genome sequencing we have a very handy lamppost to search for our keys under. Looking for germs that might cause slow diseases has not been a priority because nobody has much of a plan for how to do it.
This isn't a terribly bad strategy. It's like when I'm playing golf and I slice my teeshot toward a tangle of head-high thornbushes. I might go look for my ball on the next fairway to the right: maybe the ball happened to bounce through all the thorns an on to the short grass of the wrong fairway. That probably didn't happen, but if it did, well, I can find my ball a lot more easily than if it's in the thorn bushes. But, when my ball doesn't turn up sitting pretty on the next fairway over, I try not to be disappointed.
Similarly, with big diseases, the balls aren't sitting up on the short grass where it would be easy to find them. The 21st Century hasn't seen a lot of cases of common diseases being caused by common gene variants, just as Cochran predicted back in the 20th Century. But few are thinking about how to wade into the thorn bushes to look for them.
It is still worth studying—not just to fight the next plague, but also because it has been a major factor in human history and human evolution. You can't really understand Cortez without smallpox or Keats without tuberculosis. The past is another country—don't drink the water.
It may well explain patterns that we aren't even supposed to see, let alone understand. For example, human intelligence was, until very recently, ineffective at addressing problems causing by microparasites, as William McNeill pointed out in Plagues and Peoples. Those invisible enemies played a major role in determining human biological fitness—more so in some places than others. Consider the implications.
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Stupidly, I expected the average Jane and Joe, or at least the average Jane and Joe anchorperson or local news sort, to raise red flags about what is lurking out there in our every day lives when the HPV vaccine became available.
After all, the vaccine was cause enough for them to publicly ask, "Well, if most cervical cancer is caused by a virus contracted years before the cancer manifests, then what other cancers are also caused by such a virus? What of breast cancer? Prostate cancer, etc.? And how do we contract these viruses?"
Unless I missed it, no one made a fuss at all other than to say, "Hey, there's a vaccine for cervical cancer now and there are parents who are upset by groups who want to see to it that girls get it and parents who don't want their girls to get it." (Not much mention of boys getting it.)
They turned this huge news into a political story instead of one about breakthroughs in our understanding and prevention of disease!
I read Paul Ewald's about kissing and sex a while back. Went searching for it. Came up with a post on it from Razib at GNXP:
___________________________________
Kissing and cancer
"I recently listened to Paul Ewald talk about how a lot of cancer is due to infection on the radio show To the Best of Our Knowledge. That wasn’t too surprising, Ewald has been making the case for a connection between infection and lots of diseases for a while. What jumped out at me is his claim that kissing can spread some of the viruses. Here’s something he told Discover a few years back:
D: How do we get infected with these dangerous pathogens?
PE: Two of the most powerful examples are sexual transmission and kissing transmission, and by that I mean juicy kissing, not just a peck on the cheek. If you think about these modes of transmission, in which it might be a decade before a person has another partner, you realize that rapidly replicating is not very valuable—the winning strategy for the microbe would be to keep a low profile, requiring persistent infections for years. So we would expect that disproportionately, the sexually transmitted pathogens would be involved in causing cancer, or chronic diseases in general. You can test this. Just look at the pathogens that are accepted as causing cancer—Epstein-Barr virus, Kaposi’s sarcoma–associated herpesvirus, human T lymphotropic virus 1—and find out whether they’re transmitted this way. They almost all are. A random sample would yield maybe 15 to 20 percent of pathogens associated with cancer being sexually transmitted, yet the figure is almost 100 percent. When you look at viruses alone, it is 100 percent.
If a lot of kissing and number of sexual partners is predictive of risk of cancer, my immediate thought is that this naturally explains a lot of the cancer that runs in families. Families can pass on genes and cultural norms which would favor or disfavor certain behaviors."
May 21st, 2011 Tags: Cancer, Disease
by Razib Khan
Fascinating topic Steve.
Basically the human species has lived under an 'evolutiobary arms race' between itself and a myriad of invertebrate and microscopic nasties since time immemorial - and the immune system has born the brunt of it.
Hence I've read that the modern rise of allergies and asthma is due to our highly tuned immune systems working overtime in modern clea parasite free conditions and thus sarting to attack itself.Crohn's disease likewise.
Also consider how the prevelance of malaria has moulded very much the genotypes of various tropical peoples.
Can we at least amend some of the claims made in the linked article in The Atlantic? It's been 15 years since and it can now be said that the idea of the specific causal link between C. pneumoniae and heart disease did not pan out. Everything points to C. pneumoniae infection being simply a risk factor by virtue of inflammation it causes. Antibiotics do to heart disease nothing even remotely close to what is seen for ulcers.
Changes in common sexual practices since the 70s has resulted in widespread HPV transmission. Oral cancers are increasing in the 50+ demographic and could soon replace cervical cancer as the most common cancer caused by HPV.
Many physicians are quietly giving their teenage sons Guardasil vaccinations.
Here's a thorn bush. Pre-existing genetic condition, e.g. HLA-B27 + viral infection, e.g. Epstein-Barr = autoimmune disorder, e.g. ankylosing spondylitis. Substitute HPV, Crohns, uveitis in there and it's a really thorny bush.
"For example, human intelligence was, until very recently, ineffective at addressing problems causing by microparasites, as William McNeill pointed out in Plagues and Peoples."
The implications are that higher disease areas were not breeding for higher intelligence.
-meh
Before the Germ Theory was formulated, the best medical minds thought disease outbreaks were caused by miasmas -- invisible vapors from the center of the earth that seeped out the cracks of the crust. They were not observable, and could only be inferred when an outbreak occurred.
Racism is the USA's miasma. Although actual events of it are extremely rare, it's inferred to be an all-powerful force that causes its victims to make bad decisions about education, single parenthood, healthful practices and crime. Although the simple explanation of differential intelligence, combined with related mental skills like future-orientation, would satisfy Occam's Razor, it's against our value system to accept that explanation and we have to look elsewhere, including the invisible.
Your "writes" link goes to Cochran's Edge bio, rather than the quoted piece.
1st Anon,
Don't be too hard on the average people out there. One step away from Steve's blog toward the "manosphere" reveals they haven't, or don't want to, think about the implications either. HPV will see roughly 50% of men and 80% of women get it by middle age; the rate for men seems too low, but that's the common guess I see touted.
In light of the 80% number for women, consider that 25-27% of women will only be with one man their entire lives. Knowing that men and women get together with others with nearly the same history with men on average slightly more experienced, we can conclude that:
more than one lifetime partner means the odds are stacked against her that she has hpv.
It has been implicated in a minority percentage of heart disease as of this writing, as well as a host of other cancers.
Relatedly, I've come to believe that fatness more is an honest indicator of poor health in regards to organs and the endocrine system than the cause (although it eventually causes its own problems).
I think some fatness will be shown to be caused by the viruses harming these organs and the body is simply trying to overcome these deficiencies: create deposits of needed hormones, give the heart a needed workout, etc.
If a lot of kissing and number of sexual partners is predictive of risk of cancer, my immediate thought is that this naturally explains a lot of the cancer that runs in families. Families can pass on genes and cultural norms which would favor or disfavor certain behaviors.
This ought to be easily testable. Just look at cancer rates for the Amish, or other religious groups that sharply limit the amount of fooling around their young folk get to do before marriage. In fact a big difference in cancer rates would be so noticeable that I have to assume it isn't there, or we would have all heard about it by now.
Seth Roberts like to make this point, that billion$ have been shoveled into researching the gene theory of disease, but there's not much to show for it. And that studying environmental causes would yield a better return, but that it's less prestigious and cheaper, so it doesn't get institutional support.
I gather after the first discovery of a virus associated with cancer (in chickens), there was a lot of interest in finding other viruses that were associated with cancer. And the first round of research pretty much came up dry, because the cancer causing viruses tend to infect you a decade or two before they give you cancer, thanks to leaving genetic material in your cells (integrated into the genome or as plasmid-like thingies floating around in the nucleus), or keeping up a low-level latent infection with constant inflamation and f--king with the cells' daily operations.
Just to spell out the implications alluded to:
Typically, selection for trait X will be at the expense of other traits A, B, C... If X were unconditionally favored -- didn't hinder those other traits -- it would've already reached high frequency.
High parasite burden is unevenly distributed over the world, higher in sub-Saharan Africa than Northern Europe, for example.
Throughout history, intelligence has proved of little value in fighting infectious disease. So, contra Jared Diamond, the fight against germs won't select for higher intelligence, but for something else like sickle-shaped red blood cells.
Intense selection for anything other than intelligence probably means selection against intelligence. Higher intelligence will be selected for instead where there aren't more pressing fitness concerns, i.e. where disease burden is lower.
It doesn't look like high disease burden made people stupider, since the hunter-gatherers in Africa score lowest on intelligence, and they were least affected by crowd diseases.
But it did put a huge check on selection for intelligence in black Africa, and left it less constrained in Northern Eurasia.
Greg Cochran in his Edge response:
"Lastly, when you leaf through a massively illustrated book on tropical diseases and gaze upon an advanced case of elephantiasis, or someone with crusted scabies, you realize that any theory that explains that much ugliness just has to be true."
LOL. Leave it up to gcochran to get off a good line.
I'd add that "any theory that explains much weirdness just has to be true" and I'm thinking about odd (or in pc parlance "atypical")behaviors.
Of course, this is something both Cochran and Ewald have professed.
Obviously there is a major conflict of interest between this line of thinking and the globalism promulgated by elites that calls for open borders everywhere and in everything and for large concentrations (urbanization).
"In fact a big difference in cancer rates would be so noticeable that I have to assume it isn't there, or we would have all heard about it by now."
That's just it. We are hearing about them now.
I'll defer to Paul Ewald on this. He took part in a 100th birthday for Darwin symposium where he elucidated his theory on why sexual transmission is a major vehicle for the transmission of viruses that lead to middle age ailments. It's on youtube; hat tip to Razib at Gene Expression.
Ewald wrote "Plague Time: A New Germ Theory" ten years ago. In his book, he broached the subject of sexually transmitted pathogens and opined that they would be implicated in some common ailments, but otherwise didn't spend much time on it.
As the evidence has rolled in just in these past ten years, he's been much less timid as one can see in the symposium he took part in.
Too bad he's not a blogger.
"Changes in common sexual practices since the 70s has resulted in widespread HPV transmission. Oral cancers are increasing in the 50+ demographic and could soon replace cervical cancer as the most common cancer caused by HPV.
"Many physicians are quietly giving their teenage sons Guardasil vaccinations."
And why aren't the CDC, why aren't health practitioners, why aren't science writers addressing this (and other health risks) that arise from sexual contact? Why the hell must this be whispered?
We told gay men to stop screwing around. We told them to put a sock on it.
I think it would be kind of refreshing to hear some truths; and it would surely help parents when they try to warn kids about screwing around. (Okay, so kissing is a bit harder to argue against.)
Here is an iron-clad guarantee about public conversations:
Any post or comment thread that mentions stds will clear the room.
The Amish DO have lower cancer rates: http://medicalcenter.osu.edu/pdfs/Amish_Cancer_Rates.pdf And news articles about this do mention their "clean living" (low smoking, drinking, and promiscuity rates) as factors.
" HPV will see roughly 50% of men and 80% of women get it by middle age; the rate for men seems too low, but that's the common guess I see touted.
In light of the 80% number for women, consider that 25-27% of women will only be with one man their entire lives. "
I don't even have to look this up to know you're wrong because you are so grossly irresponsible in the rest of your statements. I've never really understood this dichotomy on iSteve; the compulsion to tread into political and scientific territory that the mainstream avoid in order to keep the peace vs a fear of sexuality verging on paranoia combined with a tolerance for male homosexuality that teeters on the verge of being a preference.
It's not advisable to engage in high risk behavior, sexual or otherwise. However, the vast majority of people who have multiple sex partners, with or without using protection, or experiment with drugs or drive too fast suffer no ill effects. You're just increasing your odds of certain kinds of mishaps. There are also numerous tales of timid souls who incur the worst consequences of risk taking behavior despite mostly avoiding it.
So, no, we won't see roughly half the population getting cancer because they're harboring HPV because they're not. HIV is the most serious STD to worry about followed by syphilis then herpes. If you're avoiding these, you're safe enough. HPV can be tested for reliably, btw, at least in women.
But if this is how you console yourself over being in absolutely no danger of receiving frequent offers for sex with strangers, carry on.
I recently listened to Paul Ewald talk about how a lot of cancer is due to infection on the radio show To the Best of Our Knowledge.
Surely, then, we must shut that radio show down.
"And why aren't the CDC, why aren't health practitioners, why aren't science writers addressing this (and other health risks) that arise from sexual contact?"
They are, but as was mentioned upthread, STD talk is a quick way to clear the room. No one is listening.
Here's a recent scientific paper.
Here's a recent popular press article.
Here's the CDC speaking about the subject and here.
ABC also has their say here.
I wonder if the germs have a long term strategy to get rid of Cochran, now that he has blown their cover?
Never again will I deliberate over a menu without wondering which bacterial colony in my gut is influencing me.
"I think some fatness will be shown to be caused by the viruses harming these organs and the body is simply trying to overcome these deficiencies: "
Interesting, or maybe fat is their favorite home and they are encouraging one's appetite. How many fat people overlook skin tags and fatty tumors which might eventually become something?
I keep thinking of the huge numbers of people with genital herpes, wondering what that bug does long-term.
In fact, as a neurotropic bug, I wonder what all those herpes viruses do long term. I don't trust 'em!
I wonder what all those herpes viruses do long term. I don't trust 'em!
85% of all people are seropositive for HSV of some type. Relax. You probably always had one.
"85% of all people are seropositive for HSV of some type. Relax. You probably always had one."
I understand that; however, the whole idea of germ theory is that the bugs we probably "always had" are probably the cause of much of our chronic and in many cases, fatal, diseases. Much will depend on our genome or on the strain of the bug, with some seriously affecting you, not me, and others seriously affecting me, not you.
Maybe narcolepsy is not a "big disease" the way cancer or heart disease is, but I recall reading Cochran and Ewald, who said over a decade ago that there might be a viral trigger for it. I paid attention to it because of an acquaintance with narcolepsy.
The illness hits those with a particular HLA type; of course, the overwhelming number of people with that HLA type will never have narco. They knew that brain cells making a particular neurotransmitter had been wiped out or almost wiped out so the neurotransmitter those cells made was either non-existent or present in only a small amount, but they didn't know why, except in only a few cases where they had identified a rare mutation) the cells were missing.
Alas, Stanford narco expert, Dr. E Mignot, went to China, where they had reported an unusually high number of cases of narco:
"A swell in new cases of narcolepsy in China followed seasonal patterns of flu, including H1N1, according to a recent study led by Dr. Emmanuel Mignot of the Stanford University School of Medicine. The new cases appear to be associated with flu infection itself, not with flu vaccinations."
Read more: http://healthland.time.com/2011/08/23/the-curious-link-between-h1n1-flu-and-narcolepsy/#ixzz1jk4JL3Gf
Of course, common strep infections are associated with weird neurological disorders in children too, such as PANDAS.
What about Toxoplasmosis, the parasite that can apparently alter the behaviour of an infected rat, increasing the chances that the rat will be eaten by a cat (in whose gut the parasite reproduces)?
http://en.wikipedia.org/wiki/Toxoplasmosis
Its presence in humans is also correlated with some personality traits.
It's been 12+ years since Judith Hooper's very good Germ Theory series of articles in The Atlantic.
It would be great if she'd re-visit the topic and report on its "progress" in the intervening years, interviewing Ewald and Cochran again.
Steve, if you talk to Cochran, ask him if he's been approached about it at all.
Thanks.
"In fact, germ theory has been so successful that it almost seems uninteresting. ..."
I wonder, (seriously, not sarcastically) if it will seem uninteresting if, in the next few years, it turns out that male homosexuality is indeed caused by a pathogen.
I suppose the news might be muted in the press, as just another bug is found to do some damage in unexpected ways, that researchers proceed to develop a vaccine or since the bug is probably common, with every child having been exposed to it, and that's that. It would cause a ruckus for a time in the homosexual activist communities, as help for deaf kids did in the deaf community, then little by little, homosexuality began to decrease.
Interesting...of course, all this is a big *if* it's caused by a bug.
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