BTW, I see you have not participated in
this thread about HERVs, ME and autoimmunity.
Any comments?
I haven't reached an opinion on that work, and I'm concerned that calling this an autoimmune disease will run afoul of misunderstanding already present concerning other diseases classified as "autoimmune". In particular the common perception that "autoimmune" = "anti-self antibodies" limits the scope to the humoral immune system. I'm convinced there is immune dysfunction, but hesitate to say more without better data.
I've been ploughing through your thread, and still unable to take it all in, but think I get the general gist, which is that HERVs may be behind a lot of infection or contamination that has been attributed to external causes.
I have also studied subjects relevant to (micro)organisms exchanging genetic material 'in the wild' so that is no surprise to me, e.g. the risks of GM crops and their commensal microflora exchanging such material with soil microorganisms and thence potentially other plants, and invertebrates carrying pathogens between plants and animals. I'm not sure that I see why domestication of animals would be necessary for such processes to occur. But I may have misunderstood.
The change is a matter of rates, not disappearance of some absolute limitation.
Domestication radically altered the environment and genetics of domesticated species. It reduced natural genetic diversity in domesticated species, even if there was increased visible phenotypic diversity between breeds, caused by artificial selection. Immunological diversity is much less apparent, and that declined. It placed species in close contact, not only with humans, but also with species they would rarely encounter in the wild. It increased the rate of transmission of infections between individuals of the same species by orders of magnitude. Anyone who has seen an entire herd or flock of domesticated cattle, sheep or chickens quickly succumb to the same disease will understand that this was a dramatic change.
There was also a great deal of change in human diets. A prehistoric politician would have had a hard time promising "a chicken in every pot" when chickens decided to move elsewhere.
On a less esthetic note, human and animal waste used to fertilize crops created new cycles of infection and parasitization. (While others may refer metaphorically to "chicken sh*t" I can speak with some authority about the real thing.)
Just as an example of how unnatural the change was, and how it relates to retroviral diseases, consider that in the wild humans suckled by other species are mostly a matter of mythology, like Romulus and Remus. Retroviruses in mammals are often passed from mother to offspring via suckling. People consuming cows milk didn't benefit from widespread Pasteurization of milk until the 20th century. Even today, we can find antibodies to BLV in people drinking unpasteurized milk.
Sorry if I have missed this, and maybe it's part of what you have actually been saying, but as such exchanges and transmissions are going on all the time, there must be a constantly-changing and evolving process of genetic recombination producing new viruses of all kinds, including endogenous retroviruses.
I think it is partly this kind of understanding that brought me to the view some time ago that the best way to protect against disease is to keep the immune system as healthy as possible, through good nutrition, fresh air, healthy work-life balance, etc. We can't avoid contact with all infectious organisms or things that could cause our own HERVs to become troublesome. And excessive cleanliness can be as hazardous as not being clean enough.
I get the impression that you credit 'modern medicine' with a greater role in human longevity than I do. I believe that there are examples of long-lived civilisations past and present that have (had) little or no contact with 'modern medicine'. I seem to recall that the UK lifespan actually decreased substantially during the Industrial Revolution, although I think that this was due to too many people living in close proximity in unsanitary conditions. In-breeding is another hazard. So there are a lot of factors affecting lifespan.
"Modern medicine" in this case includes clean water supplies, inspected food and improved waste disposal, which you seldom associate with doctors in white coats. Also, vaccination and quarantines have made substantial changes in mortality without necessarily curing a single infected individual. A great deal of other activity by M.D.s takes place without measurable effect on incidence of treated diseases. I'm working on a later post about criteria for public health.
Concerning longevity, remember that I'm not talking about the greatest age to which healthy individuals can live, but rather expected age at birth, which is strongly influenced by infant mortality. I've been through enough ancestral records to realize that the "good old days" were far from idyllic. I've also seen accounts of medieval life which convince me that people didn't really consider children more or less permanent parts of the family until about age 5. We tend to remember those who lived to a ripe old age, while records of those who died away from record keepers, often without being baptized, are scarce. The data are biased by large "sampling errors".
I won't dispute an increase in mortality rates during the industrial revolution, but consider this the result of increased population density in urban environments. As best we can tell mortality rates in medieval urban environments also went up dramatically as populations increased, and the relatively good life of the high middle ages followed a population collapse now called the Black Death. There is no question that entire villages abandoned at that time are still being discovered. In many cases we had no previous idea, from surviving records, they even existed.
I've personally run into the more recent documentary equivalent of black holes when it came to finding out what happened to people buried in private cemeteries. My horrifying conclusion in one case was that an entire family disappeared without leaving any survivors or records, and this was out in the "healthful" countryside. In a case like that, where no descendents will research ancestors, the entire tragedy simply fades from view.
With regard to concern for "excessive cleanliness", I'm guessing you don't have much experience of living completely outside modern Western concepts of hygiene. From personal experience, I can tell you actually living in such places results in culture shock for those who grew up with different ideas. There are many things you just don't imagine, and people who do know try not to talk about, because these are upsetting.
My own opinion (and it is only that) is that people who grow up on farms have better immune systems because they are exposed to significant numbers of pathogens which are not fine-tuned to infect humans. People who grow up in urban environments are largely exposed to human pathogens, and their immune systems naturally tend to identify anything unfamiliar as a human pathogen.
Beyond relatively modern farm environments, when we talk about Rousseau's "Noble Savage", we are again talking about survivors. The simple process of nature killing everyone who is not a fine specimen of the species in excellent health will produce such, even if there is no particular animus against individuals. You can benefit the species by eliminating everyone whose immune system is not the equivalent of being two meters tall from the gene pool. This is not the same from benefiting most individuals.
I think it might help if you could summarise the main points of your thread in a few bullet points, as I have found some of it rather impenetrable, and others may find the same.
I confess to an aversion to bullet points which comes from sitting through too many Powerpoint presentations while thinking that real bullets aimed at those babbling might improve matters. I've seen too many examples of people turning these into games with meaningless labels hiding the same old thinking, or lack of thinking. I'm actually trying to make people think, which is always difficult.
This is necessary because we have been through many years of people saying and doing the same things without useful results.
If I get better at pulling this together I'll create a blog post which may be better and more succinct.
), a dirty fridge, infrequent washing, dirty clothes, etc.