Wednesday, October 14, 2020

The Truth about Lice Revealed. A new discovery about the human holobiont

 "Lice Capades," an episode of the TV series "South Park." Lice are being understood as an important part of the human holobionts and, who knows? One day they may be considered as an essential component of human health, just as gut bacteria. 


Today I had a little revelation on lice. I had been writing about some recent discoveries on the beneficial effects of lice on human health and I had reported a story that I heard from my wife about people swallowing live lice as a remedy for jaundice (hepatitis b). And of people in Florence selling lice just for that purpose. But I wasn't sure if it was a real story or a legend. 

But, today, I heard a talk by Maurizio Naldini, a Florentine journalist, who told several stories about the Florence of his youth. And, yes, he had met in person the woman who sold lice! It was true: people would buy lice in Florence as late as some 50 or 60 years ago. 

The curious thing about this story is that Mr. Naldini had no idea of why people bought lice and what they did with them. So, he listened with great interest to my wife telling him the story of lice being swallowed inside a wheat wafer to cure jaundice. 

In my case, hearing Mr. Naldini had a different effect. Now that I knew that the story was most likely true, then I could examine it more in depth. Of course, the idea that lice would suck out the bile of jaundice makes no sense. Swallowed lice (dead or alive) can hardly suck anything. But then, why would people do such a thing? 

Of course, there is a tradition for people paying good money to do the strangest things when they are sick and they think something can help. CBS has a list of the 15 most bizarre (and disgusting) cures ever invented, and it is surely interesting to learn about such ideas as placing a dead mouse in the mouth to cure toothaches or using crocodile dung as a contraceptive. But they don't mention lice!

Yet, even the most bizarre ideas have an origin and I think that the lice market of Florence had a justification, probably better than that of crocodile dung. It has to do with the concept of holobiont, the fact that the human body (just as that of most animals) is an incredibly complex assemblage of creatures. Most of them very small (bacteria and viruses), some a little larger (lice and others), and with the actual human organism as just one of the many, although surely the biggest. 

Now, holobionts exist, and if something exists it means there are good reasons for it to exist. Most of the creatures that populate the human holobiont are there for a reason. Maybe they are just harmless commensals but in many cases, they are useful symbionts. And that may well be the case of lice, too. 

I already mentioned a study that found "Unexpected Benefits from Lice." The little critters seem to boost the human immune system. But there may also be another benefit. You see, there are three kinds of lice inhabiting the human holobiont: the body louse, the head louse, and the pubic louse. 

Of these three, the only one that may be harmful to human health is the body louse. It may be because it is a relatively recent human parasite having developed in parallel with the use of clothing. But another study argues that the "good" head lice can be beneficial in stimulating the development of an immune response against the "bad" body lice. So, if you have (or have had) head lice, you are healthier.

Perhaps this is the key to the story of the market of lice in Florence. Ancient Florentines knew little about immunity, but they may well have noted that people who had head lice were less prone to have body lice. Perhaps even that head lice could help people get rid of body lice.  Lice don't jump around or fly, so moving from one body to another is not so easy. And so they would ask their friends and relatives if they could give a hand in passing lice to someone who was lice-deprived. Then, why not? Some enterprising people thought they might make a little cash by providing others with a commodity that was needed: lice. 

Maybe this was the origin of the legend that my wife told me. Once that lice were understood as beneficial, it was natural that they could be tested on other kinds of illnesses. Then, the placebo effect would convince people that lice were effective in curing jaundice. With the more enlightened (so to say) 20th century, lice of all kinds became anathema and a social stigma, But the idea that you could eat lice in a wafer to cure a rather stubborn illness such as jaundice remained for some time. 

It is an interesting story that goes in parallel with that of the discovery of the bacterial flora in the guts. Some people understood right away their importance and their beneficial effects, but others thought that it was not hygienic having bacteria in your guts and thought it was a good idea to get rid of them. Now, of course, you buy probiotic supplements just to get more good bacteria inside your guts. Who knows? Maybe one day it will be fashionable to buy head lice in a pharmacy in order to prime people's immune systems!

And this is the story. The more things you know, the more you discover. And so, onward, fellow holobionts!


Note: After publishing this post, I received a link from Jan Barendrecht to a paper that describes how swallowing lice was considered a therapy for several kinds of illness in Spain. But not just in Spain. The authors say that: 

Numerous authors show that using animal resources as therapy is a widely distributed atavistic practice [,], a fact that is demonstrated by the use of head louse against jaundice in distant geographical areas [,]. Its use is particularly common in the Hebrew culture. Izaak Walton in his famous book “The Compleat Angler” (published in 1653) records that the Jews were the first to say that swallowing live lice is a good remedy for jaundice []. For their part, the German rabbi Yair Bacharach (1639–1702), author of the collection of responsa known as “Havvot Yair” (“Villages of Yair”), indicates that the patient should take 8 lice taken from his/her own head–see Rosner and Bleich 2000 []. Ben-Ezra in 1949 recorded in Horodetz (one of the oldest Jewish communities in Russia-Poland) the introduction of lice in an omelette as treatment []. In Latin America there are also references to this medical practice. In this case, the remedy would have been brought by the Spanish conquistadors and assimilated by the Spanish American folk medicine in an eclectic form []. The recommended number of specimen to take in Chile, Peru, Guatemala and Argentina is 4 or 5 with examples found using measures such as a thimbleful [-].

Saturday, October 10, 2020

It is a Lion! It is a Goat! It is a Snake! No! It is a Holobiont!


Maybe 25 years ago, my friend Susan came from California to visit me in Florence. She saw the statuary piece of the Chimera of Arezzo and asked me what that was supposed to mean. I said, "I don't know for sure, but I'll find out." 

That involved much research, papers written, a blog created, and an entire book in Italian. And yet, I can tell you that I was yesterday night that understood what a Chimera really is. Just before falling asleep, I had this flash: here is it: A holobiont! So obvious!

And that's no mere definition: it opens up a whole new layer of interpretation of the chimera as a horizontal contamination of memes. Memes do replicate horizontally, just like bacteria do. Truly mind-blowing, I am still shocked by what I was thinking yesterday night. 

There will be more on this, but for the moment I just wanted to mention this discovery to you. Life is beautiful when you can think of such things!

Wednesday, October 7, 2020

How Your Gut Microbiome can make you Smart or Dumb


Deric Bownds discusses how fecal transplants from old mice to young mice have bad effect on the critters' mental abilities. Maybe the opposite is also true. And maybe it works also for humans.
It seems that your microbiome can make you smart or dumb. Holobionticity is a complex matter, indeed! 

Age related cognitive decline and the gut microbiome

by Deric Bownds

Haridy summarizes experiments by D'Amato et al. showing that fecal transplants from old mice to young mice result in the younger animals displaying learning and memory impairments. It would be interesting to expand this work to check whether transferring fecal transplants from young to older mice improved their learning and memory, as is the case with blood transfers from younger to older mice. Here are the background and results sections of the open source research paper


Saturday, September 26, 2020

Unexpected Symbionts: What if Your Health could Benefit from Creatures you Normally Despise?


"Lice Capades" (2007). An absolutely wonderful episode of the "South Park" series. The world as seen from the viewpoint of lice. Fantastic. 

In Italy, there is a legend that says you may be cured of hepatitis b (jaundice) by eating lice. It is not just a vague legend, I personally know people who swear they were cured of jaundice by doing exactly that. Apparently, in the 1960s, there were still people who sold live lice packed in a small wafer (where they got the little beasties is anybody's guess). No trace of this story can be found on the Web nowadays, I can only relate it from what relatives and acquaintances tell me. But I have no reason to doubt that it was a common belief some 50 years ago, although it may have been limited to Tuscany, or perhaps only Florence. There are reports of people eating lice in other cultures and, of course, monkeys, apes, and other furry animals do that all the time. 

About this story, let me say that I am a big fan of evidence-based medicine and I am the first to doubt this story (and, also, I never had lice in my life). But, once you acquire the concept of "holobiont," you start reasoning that lice must have accompanied the human organism for millions of years. And, if they did, there has to have been some reciprocal adaptation and -- why not? -- mutual benefit. Of course, as a human being, you won't even remotely imagine that lice may be good for your health. But are you sure? 

At this point, you start searching the web and, surprise! (or maybe not), you immediately find an article titled "Unexpected Benefits from Lice" Look, this is serious stuff, evidence-based, not old folks' tales. And they say: 

Parasites such as lice have a role in the conditioning of a 'natural' immune system and reducing the likelihood of immune dysfunctions,

Of course, that's true for mice, but there is no reason to believe that it wouldn't work for human organisms, as well. Some people have said exactly that, "lice can be good for you." Maybe that's a bit optimistic but, surely, there is no reason to fall into hysterical reactions when dealing with lice in children. In some cases, lice may be bad for your health, but the little critters are not a major threat.

So, may lice be a symbiont rather than a parasite? As usual, the boundary between the two categories is fuzzy. Likely, no creature living inside the human holobiont is 100% parasitic. Most of those that lived with us for millions of years surely have at least some beneficial effects. And let me tell you just one thing: my mother-in-law holobiont had flatworms for most of her life. She turned 100 two months ago and she is in reasonably good health for her age. Would there be a correlation? At least, you can't rule that out!

You see how ideas interlock with each other and branch out generating new ones? Once you have the concept of holobiont, you have access to a whole new host of concepts. It is the beauty of the world we live in: truly Gaia takes many forms!

Saturday, September 5, 2020

The Evolution of Human Empathy: From bronze age warriors to us, and beyond

 The human mind is the most complex entity we know in the whole universe. One of the fascinating things about it is how it has been evolving over time. What could have been the thoughts of a bronze age warrior? What thoughts did an ancient hunter-gatherer think? Why do we think we day we do, nowadays? As Sir Thomas Browne said, these are puzzling questions, but, like the song the Sirens sang, not beyond all conjecture. And here I am presenting a sweeping review in this area that starts with the work by Julian Jaynes on the mind of our remote ancestors, connects it with the most recent result of genetic studies, and even tries to peer into the future: how will the human mind evolve? Another question not beyond all conjecture. We may be moving toward much more complex and intricate forms of empathy than those we know nowadays.


The Mind

The mind is a tool, this much is clear. Of course, it is a special tool, able to do many things in many fields. But it is a tool and it has evolved to perform the tasks it performs. Do you remember Darwin's finches? They are birds with beaks of different shapes that were the source of inspiration for Darwin's idea of evolution: the beaks adapted to the different kind of food eaten. The human mind does the same. If it is like it is, nowadays, it is because it is functional to what it does. 

That applies also to the entity we call consciousness. We can define it as the capability of "modeling oneself" just like we can model other people's behavior in order to predict it. You probably heard the story of the "mirror neurons," brain structures specialized in understanding the behavior of other people. In a way, it means reading other people's mind. Your dog can do the same: dogs have mirror neurons, too. You can use the term "mirroring" or also "modeling." It doesn't matter the term. if you can model other people's behavior, you have a certain degree of empathy. And, very likely, high empathy and self-consciousness go together. They are two axons of the same neuron. 

Empathy is surely useful for us in many circumstances (also for dogs). You need to know if the person you have in front is there to help you or he wants to use his battle-axe on you. But that doesn't require much effort in terms of sophisticated mind-reading. Where modeling truly shines as an evolutionary tool is in the mating game. At least in our modern world, the competition for mates is fierce and ruthless and it involves many factors. Surely money and status count, but empathy does a lot as the capability of mirroring your perspective mate, that is behaving in a way that you know that he/she will appreciate. Ask any pick-up artist about that and he'll confirm that it is the tactic they use. Also, if you ever chatted with a professional sex worker, you may have noted how they have an uncanny ability of reading your mind and say exactly what they know will please you. The whole game is played by modeling another person's mind inside one's own

So, it is no surprise that most of the modern literature and fiction deals with what we call "romance," men and women getting together. We seem to be deeply interested in the courtship rituals and about everything involved with it. It is one of the top skills of our mental arsenal. But have we always been like this?


The Evolution of the Mind

At which point in their evolutionary history did humans develop this exquisite ability of reading each other's minds -- including their own -- that we have today and we also call empathy? There are cartoons that describe cavemen using their stone axe to stun a woman before pulling her by the hair all the way into their cave, but that's of course a little unlikely to have ever been our ancestors' behavior, to say the least! But how did cavemen woo their women? Of course, the entity we call the "mind" leaves no fossil record, so what do we know about the empathy capabilities of our remote ancestors?

The first to pose this question was Julian Jaynes with his "The Origin of Consciousness and the breakdown of the bicameral mind" of 1976. It was a milestone in the field: Jaynes analyzed ancient written records and he concluded that the people living during the bronze age were not really "conscious" in the modern sense of the term. They had what Jaynes called a "bicameral mind." They would "hear voices" in their minds and act accordingly, but we have no evidence that they had the kind of self-recognition that we normally have today.  

The idea of the "bicameral mind" as described by Jaynes has been often criticized and, indeed, there is no proof that the inner mechanisms of ancient minds worked the way he proposed. But it doesn't really matter whether the "voices" are the result of the interaction of the two halves of the brain or they originate in some other sections of the brain. The point is that the behavior of the people described in such documents as the "Iliad" or some books of the Bible is completely different from that of modern people. The ancient just seem to lack empathy, they act like automata, without evident feelings of love, compassion, or concern for other people. In modern terms, we would define bronze age people as "autistic." Maybe it is a literary style, but Jaynes' idea that people truly behaved in this way makes a lot of sense. 

Just as an example: think of the Iliad. The story start with Paris, a Trojan prince, stealing Helen from her husband, Menelaus, king of Sparta. Then Paris is killed, and Helen marries another Trojan, Deiphobus. Finally, Menelaus kills Deiphobus and takes Helen back. Does the Iliad report of anyone caring about what Helen feels during these events? Was she unhappy, concerned, sorry, or something like that? No -- nobody gives a war cry about that. Another example: consider the case of  Tamar and Judah, as reported in the Genesis. In the story, the only problem for Tamar is how to give children to Judah's clan despite the death of her first and second husband, both sons of Judah. And nobody cares about what Tamar feels. Nor, there is any feeling or care for what Tamar's husbands feel, or pity for their fate.

Now, let expand the discussion a little. Jaynes had only written data, so his analysis couldn't go further back than the 3rd millennium AD, more or less. Before that age, there are no written records, at most pieces of statuary that might be interpreted in various ways, but that don't tell much to us about how people thought or behaved at that time. 

But we now have genetic data that, amazingly, give us a chance to go well  beyond the "literacy limit." I refer to the recent discovery of the "Y-chromosome bottleneck" in humans (Karmin et al., 2015). I described these findings in some detail in a previous article on "The Proud Holobionts." Here, let me summarize these results.


The figure above, (Karmin et al., 2015) reports the degree of diversification of the human Y-chromosome and of the mitochondrial DNA (mtDNA) over time. Both are elements of the genome that are passed only from male to male (Y-chromosome) and female to female (mtDNA). So, the curves are roughly proportional to the active male/female reproducing population. 

For most of the record available, some 50 thousand years, the population of reproducing males is smaller than that of the females, roughly a factor of three. It doesn't mean that there were less males than females in these populations. Then as now, the male/female ratio for the people alive at any given moment was approximately equal to one. But not every human being manages to leave descendants: many disappear from the genetic history of the species. For some reason that would be long to discuss, females are normally more successful than males at that and that's what we see in the curves of the study. 

But the study shows an impressive and unexpected feature. A "bottleneck" in male diversification that takes place between 7,000 to 5,000 years ago. In this period, there was only about one reproducing male out of 20 reproducing females. 

If we now compare with Jaynes' data, we see that he placed the bicameral mind as existing approximately during the 3rd-2nd millennium BCE, while the breakdown took place during the late 2nd millennium, roughly with the end of the bronze age. So, Jaynes' time window overlapped in part with the bottleneck. What he was seeing was the climbing side of it. He saw modern consciousness appearing (re-appearing?) with the male reproductive effectiveness gradually regaining the normal value of 1:3 with respect to the female effectiveness after a period of eclipse.


Interpreting the data

We said that the conscious part of the human mind is mainly a tool used to find sexual partners. So, the mind must have adapted to the social and economic structures of society as they changed and evolved. Then, let's start from the beginning, the left side of the curve reported by Karmin et al. from ca 50.000 to 10.000 years ago. We see that during that period the average the reproductive success of human males was about the same as it is today, that is one male reproduced for about three females .

We know in those remote times, humankind was mainly practicing a hunting and gathering lifestyle. What were people's minds like at that time? Of course, we have no written records from those times. But we still have hunter gatherers around in our world, so that we can have some idea of how they think. Helga Ingeborg Vierich has lived with hunter-gatherers and she reports that they are kind and considerate, and rarely polygamous. In their societies, males have about the same chance as females to marry outside the group. Women have positive roles in society, separate but not inferior to the roles of males. On this point, I can also report my personal experience with the Roma (the Gypsies) who are perhaps the closest approximation to a hunter-gatherer society existing in Europe nowadays. In terms of empathy, I can tell you that their skills in reading the mind of a gajo (a non-Rom) are nothing less than exquisite. If empathy is a useful skill in a monogamous, relatively egalitarian society, then our hunter-gathering ancestors clearly had it, just like our modern hunter-gatherers do (and the Roma, too).

Then, there came the "bottleneck" that corresponds approximately to the end of the Neolithic and the start of metalworking, first copper then bronze. As it normally happens, technology changes society, sometimes very deeply. The bronze age saw people moving away from the traditional hunting-gathering lifestyle to that of farmers and pastoralists. It is normal (but with plenty of exceptions) that pastoralists tend to live in patrilinear "demes" (you can call them "clans"), a term used in biology to indicate groups in which individuals tend to mate mainly with other members of the deme. 

In human patrilinear demes, males tend to remain within the deme, while females are more mobile and move from a deme to another (it is called exogamy). In this kind of society, women marry a clan, not a person, just like Tamar did in the Biblical story. Even in the case of Helen of Troy, the story of her abduction may refer to a form of exogamy.

In this kind of patrilinear societies, we can imagine that there is little need for either males or femals to develop the kind of empathy that we moderns need. Neither Paris nor Helen are reported in the Iliad to have been "in love" with each other in the modern sense of the term. There is nothing romantic in their relation. In general, if a woman marries a clan, then she doesn't care whether the male they mate with is nice, considerate, and gentle. What counts is how many sheep the clan has. Maybe this is a little schematic (a lot), but it seems to fit with what we know of the age described by Jaynes. 

These genetic data are in line with the interpretation that the age of the bottleneck corresponded to an increasing population of pastoralists living in patrilinear demes. This is explicitly discussed a 2018 paper by Zeng et al. They explain the bottleneck as due to evolutionary competition between demes, rather than individuals. A deme can "die" either because it is outcompeted by the others for scarce resources or because its members are killed in battle. Since the males in a deme are closely related to each other, there is a good chance that, when the deme dies, their Y-chromosome disappears from the human genetic history. Females, instead, owing to their exogamic habits are more likely to have their genetic signature survive, being spread over several memes. 

Can these social changes affect the genetic build-up of the human mind? We cannot say for sure, but don't forget how powerful evolution is in shaping the functioning of living creatures. The whole "bottleneck" episode lasted a few millennia and Cochrane and Harpending suggest in their "The 10,000 year explosion," that the human genome could change significantly in such a short time. For instance, they note that bronze age people had a significant brow ridge that was later mostly lost. Human females of the late bronze age didn't seem to like this feature very much in their males, just like modern human females don't. And no amount of cultural change can make you gain or lose a prominent brow ridge. 

But it is not really fundamental to decide whether the big changes we see across the bottleneck are genetic or cultural: let's just say that they occurred, quite possible because of a mix of the two factors. Then, everything clicks together, more or less. The bottleneck was caused by the rise of a patrilinear society organized in small demes, then it disappeared when the demes were superseded by new social organizations: cities, states, and empires. Kings and emperors didn't want their subjects to fight tribal battles against each other. So, they broke the deme structure in various ways -- they never were able to eliminate them completely, but their importance was enormously reduced. With this, the old bronze age "bicameral" mind became obsolete. And evolution did its job: what is not needed or is harmful, disappears.

The rise of monogamy

Over the past 2-3 thousand years, we see rigid clans mostly disappearing and a certain degree of egalitarian society developing. Monogamy becomes more and more common, at least for the average people (kings and emperors are not bound to their own laws). Monogamy was not only a social custom, but often enforced by laws and by religious commandments. The main reason for this development is that monogamy is a useful feature for a military empire (and all empires are). Armies need soldiers and cannot tolerate that soldiers fight with each other for females. Instead, if every male has one female, at least on the average, there is no need for internecine fighting among males to hoard as many women as they can. And so all the men of the empire could be turned into fighters to use against external enemies. Then, if the state takes care of enforcing monogamy, soldiers can embark in a long campaign in remote lands knowing that, at least theoretically, their wives will be waiting for them. The Romans, the paradigmatic military society in history, were strictly monogamous, at least with respect to the marriage of Roman citizens. That was typical for most empires in history.

Monogamy may be one of the main reasons for the development of the emphatic mind we all have. If you live in a relatively egalitarian society, you have a large number of potential partners: choosing the best one becomes a difficult game that requires sophisticated empathic capabilities in order to convince a perspective mate that one is the right partner for him/her. It is a game where you have to deploy all sorts of strategic skills to optimize your chances. And it is a risky game: you may not be able to find the right partner or you may need to settle for a less-than-perfect partner. You may know the story of the man who had decided he would never marry until he could find the perfect woman. And after much searching, he found her. The problem was that she was looking for the perfect man! 

So, you see how difficult the game is, and you probably experienced that yourself. For sure, bronze age people wouldn't do too well at it: imagine a bronze age warrior walking into a modern ballroom. He would stand in front of a girl and state, flatly, "God told me that you are to be my woman." Not exactly the best strategy to win the hearth of the prom queen.   

Then, of course, monogamy was never perfect and it was always accompanied by the activities that we call "philandering" for males, while for females we use terms such as strumpet, harlot, trollop, slut, or whatever. It doesn't matter, it is still the same game and it requires empathy. Married women have sophisticated ways to let men understand that they are happy to be wooed. But no modern woman would be interested in an affair with a bronze age man, no matter how many sheep he has. And no bronze age woman would be interested in an affair with a man who doesn't have any sheep. Empathy rules the game, that much is certain.

So, we can explain why the Western civilization has developed so many examples of what we call today "romantic fiction," from the saga of King Arthur, to modern telenovelas. It is probably a form of training for young minds that emphasizes such feelings as romantic love and typically involves a couple of lovers who face all kinds of obstacles but who, eventually, are reunited all thanks to being faithful lovers. This kind of fiction would be most likely totally incomprehensible by our ancestors. Imagine asking Tamar (the one of the Genesis) "but do you love your husband?" I can see her face looking like if you had asked her, "do you like French cuisine?" Some people have tried to cast Tamar in the role of a modern character with results, well, lets say not completely satisfactory (more details at this link).


The Final Question: How about the future of the mind?

After a few thousand years of prevalence, monogamy is clearly in decline. It never was perfect but, once, it was enforced by law and customs and, in some countries, you can still be stoned for being an adulteress. Even divorce used to be illegal in many Catholic countries. Today, these rules have mostly disappeared, although 19 US states still define adultery as a crime and there exist two countries in the world where divorce remains illegal, the Philippines and the Vatican. 

This relaxation of the monogamy rule can be explained as the result of the decline of the role of males as fighters. Up to a certain time, not many decades ago, wars were won by the state that could line up the largest number of poor clods in uniform and have them march forward while being shelled by the enemy artillery. That's not so important anymore and the development of drones and war-robots has made the very concept of "soldier" obsolete.

The current situation is basically unheard of in the history of humankind. There has never been an age in which males had become useless as military machines. This point may not have been understood by the leaders, yet, but it seems clear that, if there is little or no need males as soldiers, there is little or no reason to enforce rigid codes and laws on sexual behavior for them and their wives

That's rapidly modifying the standard way of thinking about sexual codes of conduct, especially in the West, even though we can probably rule out that it is modifying the human genetic code (yet). In any case, the current way of thinking of Westerners is as far away as that of bronze age warriors as it could be. The focus on mind-reading is being turned to one's own mind and modern Westerners can be defined as extreme cases of narcissists, interested only in their own well being. It is what we call the "me-generation."

The problem with the me-generation is that it is generating a class of people who think they can do everything that pleases them. And the only thing that's worse than a narcissist is a rich narcissist. One of the things human males like to do is to hoard women in personal harems, as it was the use in some societies in the past. So, if a male is both a narcissist and he has enough power in the form of money, what can stop him from having multiple female partners in the form of occasional or stable concubines, or even in the form of a traditional harem? 

The current laws and customs prevent the men in the most visible positions from explicitly expressing their sexual habits, but if you look at the recent sex-scandal involving Jeffrey Epstein, you can notice that there are things going on with our leaders that don't appear in the media. Even without concubines or harems, already now, we might say that in the West the elites enjoy "time-dependent polygamy," in the sense that they periodically switch from an older wife to a younger one. That, of course, deprives young and poor males of suitable female partners, but it is the law of money. In time, we might see the development of a rigidly stratified society where the elites accumulate women just like they accumulate money. 

Then, if women are seen as accumulated capital, there follows that methods are needed to make sure that they are not stolen or lost. Eunuchs are a traditional way to keep women in their place -- and they also help solving the problem of excess males. But there are even more invasive methods to control women. Several societies in our time practice "female genital mutilation." The idea is that if a woman feels pain during sex, she will be less interested in cheating her husband (or harem master). In its extreme form, infibulation, the woman is treated like a coffer that can be locked and unlocked at will. Female genital mutilation is not so popular nowadays in the West but, who knows? Fashions change so rapidly!

Chances are that someone who owns a harem of infibulated women doesn't think of them in terms of romantic love, not any more than one of our billionaires have romantic feelings for their stock portfolio. Indeed, it is often reported that the rich are nasty, unfeeling, and uncaring for others. That's what you would expect. Why would the rich need to care for others? They don't need empathy-based skills. Then, the women in a harem would hardly be thinking of their master as someone to love in romantic terms. To say nothing about the eunuchs. 

So, if these habits were to become the rule in the future, then the human mind could change, culturally and perhaps even genetically. Evolution, cultural and genetic, does it work of eliminating those features that are not needed, think of the wings of the dodo bird. So, the sophisticated empathy capabilities that we had developed over the past 2-3 thousand years could disappear in a few centuries. Then, future scientists may discover a second bottleneck in the human Y-Chromosome diversity and wonder what caused it.

But there are other possibilities and it is not farfetched to think that the next step for society will be to discover that the modern obnoxious alpha-males and their manic sex-habits are not only useless, but expensive and dangerous. So why don't we just get rid of most of the males, leaving around just the tiny number needed for reproduction? After all, it is a choice that ants and bees made millions of years ago. Their social organization is called "eusociality" and human society already has some of its characteristics, so that it can be defined as "ultrasocial".

Is it possible to transform human society in such a radical way? Why not? We evolved, and we keep evolving. Already, the features of our society would be completely unrecognizable to someone living just a few centuries ago. And if ants and bees (and also the naked mole rat) evolved toward eusociality, there is no reason to think that we can't follow the same steps. Nate Hagens has been discussing how our society is already moving toward what he calls the "superorganism" -- a term used also for anthills and beehives.

Our society is already much more complex than the patrilinear demes of the Bronze Age and a future eusocial version would be even more complex. In the network of complex subsystems we live in, and in those in which we may live in the future, empathy deals with many more things than just finding a sex-mate. As Chuck Pezeshki notes, empathy is not a rigid concept, it is a process that evolves toward more complex and sophisticated forms (this figure is from Pezeshki's blog).

So, humans might be moving toward a version of empathy that will be highly sophisticated and structured as it can be in a universe that we are perceiving as more and more complex, a hierarchy of systems that we call "holobionts" and that culminates on this planet with the highest level holobiont of all, the entity we call sometimes "Gaia." Developing this kind of empathy could place humans truly in harmony with nature and with their own species. It would be a form of empathy that we can imagine as connected to what we call today the "religious experience." And maybe they'll perceive things that current humans cannot even imagine. It would be the "revelation through evolution," a concept that Michael Dowd has perceived. The Goddess Gaia revealing herself in her full glory,

And onward we go, evolving all the time. 


h/t Michael Dowd, Chuck Pezeshki, Nate Hagens, Maria Mercedes Sanchez, and Helga Ingeborg Vierich,

Friday, September 4, 2020

The Global Cycle of the Pandemic: The Ebb and Flow of the SARS-Covid-2


This is not a post directly related to holobionts, but being infected by viruses is part of our being holobionts. (See below for the Italian version of this post)

This is my first post for the "Pills of Optimism" group - a group of Italian researchers and experts headed by Professor Guido Silvestri who try to spread scientific news and views on the pandemic. The group is made up mainly of medical doctors and experts in medicine, which - of course - I don't even dream of being. But I think I can make a modest contribution with my experience with models and data analysis. Among other things, for those who read this blog, you may be interested to know that the equations that describe the standard viral propagation model (the one called SIR) are exactly the same as those that describe the extraction cycle of a mineral resource (the famous "Hubbert model").

So, I agreed to run this weekly column that tries to take stock of the international situation, bringing data and analysis that go beyond the daily media reports, always in search of sensational news. Apart from my posts on the international situation, the authors who publish on "Pills of Optimism" deal with various topics related to covid-19, the situation in Italy, legislative issues, legal problems, treatments, vaccines, and many other things. These posts are achieving considerable success, a clear sign of the need for objective and scientific information that is not found in the media. For example, the post below had over 500 shares just an hour after publication. A lot of people commented saying, "but we didn't know these things!" Yet, they are just a click away: they are public data. But,  people still see the world according to what they are told in TV.


By Ugo Bardi - Lecturer at the Chemistry Department of the University of Florence, where he deals with mathematical models applied to the ecosystem and climate change. (1)

💊💊💊The global pandemic seems to have started its decline. Some countries are still seeing growth but, overall, the trend is downward, as the WHO has also recently noted. This is good news, although it will still take time for this epidemic cycle to end.



With this post, I am starting a series of contributions on the international situation of the coronavirus pandemic. We will see what the various states and regions have done, with what results and, by comparing the different histories, we will try to make an informed judgment on the validity of the various choices. We will not speak directly of Italy (for this there is an excellent daily "Pill" written by Paolo Spada), but we will often make comparisons with the Italian situation.

The analysis you will find in these "international pills" will be all based on available data, no partisan politics, no flights of fancy, no conspiracy hypotheses, nothing of the kind. Obviously, data alone are not enough: they must be evaluated and interpreted, and for this we need models. But in every key case of the future lies in the past, so it is only by means of quantitative data that we can understand what happened in the past and then evaluate what may happen in the future.

Let's start today with the most general case, that of the whole world. You can see the data in the figure below (taken from "worldometer" (2)). They are curves that represent both the number of positive cases per day and the number of deaths. Notice immediately that the mortality curve shows a clear trend of decline while that of the number of cases has not increased for over a month. This "stalemate" in the epidemic has also recently been noted by the World Health Organization (WHO) (3).

You may find this result surprising. Indeed, almost everyone is convinced that the pandemic is still growing everywhere. This impression probably comes from the fact that the media tend to report the numbers of the day without bothering to evaluate them in the context of the general situation. Another problem is that we often hear that the epidemic tends to grow "exponentially" - that is, more and more rapidly. But this is absolutely not true. No epidemic (as indeed no physical or biological phenomenon) grows exponentially except in its initial stages. All epidemics follow a cycle where the rate of growth increases at the beginning, but then gradually slows down and eventually begins to decline.

This is what we see in all historical cases and it is not surprising that this is also the case with the covid-19 pandemic. In the early stages, the virus finds many easy targets in humans whose immune systems are unprepared to fight it. Thus, it spreads rapidly. Over time, the number of suitable targets decreases as already infected people develop some degree of immunity. In some cases, the virus itself tends to mutate and become less lethal. The result is that the num
ber of cases and deaths slows down, peaks and begins to decline. In the long run, the epidemic disappears: no epidemic lasts forever. After some time, the cycle can begin again with the virus mutating into new forms. Certain epidemics, such as those of the flu, are typically seasonal. They come back every winter (in the Northern hemisphere) and then disappear in the Summer (4).

In general, epidemic cycles tend to follow "bell-shaped" curves. They are also described with names such as logistic, Gompertz, Bass, and others. More generally, the most common theory that generates these curves is called "SIR" from the initials of "Susceptible, Infected, Recovered" (5). These curves are never exactly symmetrical and in many cases you see more than one cycle due to various factors, but that is the trend.

For several European countries, the epidemic cycle curve was very sharp, showing a slightly asymmetrical bell shape with a peak in April. Since then, the pandemic has been on the decline in Europe. In recent times, some countries (including Italy) are seeing a rise in the number of cases, which however does not generate a corresponding increase in mortality (2). In large part, this is due to the increase in the number of tests being done.

For the whole world, however, the curve did not show a well-defined bell curve. This is due to various reasons. First, there is a geographical factor. The virus has to travel vast distances from one region of the world to another, and this takes time. Then, there are climatic factors: it is known that the spread of viruses that affect the respiratory system occurs more easily in winter (3, 6). There are also random factors: someone who travels by plane can quickly carry the infection even over great distances. Finally, there are factors related to the measures taken to avoid the spread of the virus, lockdowns, distancing, etc. These measures have been implemented in different wayus in different states and regions and their impact is difficult to quantify.

These factors explain the shape of the pandemic's planetary curve. The virus first spread to China, then moved to Europe. Then it crossed the ocean, spreading to North America. Still later, it crossed the equator. In the Southern hemisphere, the epidemic cycle was out of phase by about six months ahead, because it is still winter there now, in meteorological terms. All these region-to-region jumps have deformed the curve as a result of overlapping the cycles in the various regions.

Today, the virus no longer has virgin territories in which to spread. It remains growing only in certain regions of the southern hemisphere and in India, but even in those regions the epidemic shows signs of slowing down. Thus, it seems likely that the drop in the number of deaths we see is a result of the saturation of the infected population. In short, good news, the pandemic is not over yet but it seems that we have "bypassed" the worst phase. But what happens now?

There are those who have proposed bold long-term forecasts based on mathematical models (7). There is talk of a resurgence of the epidemic, of a "second wave," of the effects of various types of vaccines, and many other things. But there are too many variables and too many unknowns to make us able to say something meaningful today about what will happen in 2021. As Andrea Saltelli and his collaborators said in a nice article in "Nature" (8) "The mathematical models are excellent to explore the questions, but dangerous to claim to have answers. " You have to be very careful with the models, because after a while you work on them you risk convincing yourself that the models are reality and this leads to all sorts of errors and disasters (9, 10).

For the moment, let's be content with knowing that the epidemic is no longer growing and that it seems to be starting to wane. For the future, let us remember that living cells, of which we too are composed, have coexisted with viruses for billions of years (literally!) (11) and that viruses are not necessarily pathogenic or harmful (12). Let's not expect miracles: we will have to continue living with them, as we always have.

The author thanks Sara Gandini and Maurizio Rainisio for their comments and suggestions on this article.



The Original post in Italian

Questo è il mio primo post per il gruppo di "Pillole di Ottimismo" -- un gruppo di ricercatori e di esperti che fa capo al professor Guido Silvestri e che cerca di diffondere notizie e punti di vista scientifici sulla pandemia. Il gruppo è formato principalmente da medici e esperti in medicina, cosa che -- ovviamente -- io non mi sogno nemmeno di essere. Ma credo di poter portare un modesto contributo con la mia esperienza con modelli e con l'analisi dei dati. Fra le altre cose, per quelli che leggono questo blog, vi potrà interessare sapere che le equazioni che descrivono il modello standard di propagazione virale (quello detto SIR) sono esattamente le stesse di quelle che descrivono il ciclo estrattivo di una risorsa minerale (il famoso "modello di Hubbert"). 

Quindi, ho accettato di tenere questa rubrica settimanale che cerca di fare il punto sulla situazione internazionale, portando dati e analisi che vanno al di là delle sparate giornaliere dei media in cerca di notizie sensazionali. A parte i miei post sulla situazione internazionale, i vari autori che pubblicano su "Pillole di Ottimismo" si occupano di vari argomenti correlati al covid-19, la situazione in Italia, le questioni legislative, i problemi giuridici, le cure, i vaccini, e tante altre cose. Questi post stanno ottenendo un notevole successo, segno evidente della necessità di un'informazione obbiettiva e scientifica che non si trova sui media. Per esempio, il post che trovate qui sotto ha avuto oltre 500 condivisioni dopo poco più di un'ora dalla pubblicazione. Molta gente ha commentato dicendo, "ma noi queste cose non le sapevamo!" Eppure, sono a portata di click: sono dati pubblici. Ma, tutt'ora, la gente vede il mondo secondo quello che gli raccontano in televisione.


Di Ugo Bardi -- Docente presso il dipartimento di Chimica dell’Università di Firenze dove si occupa di modelli matematici applicati all'ecosistema e al cambiamento climatico. (1)


💊💊💊La pandemia globale sembra aver iniziato il suo declino. Alcuni paesi vedono ancora una crescita ma, nel complesso, la tendenza è alla discesa, come ha notato anche recentemente l’OMS. Sono buone notizie, anche se ancora ci vorrà tempo perché questo ciclo epidemico si esaurisca.💊💊💊

 Con questo post, comincia la mia serie di contributi sulla situazione internazionale della pandemia da coronavirus. Vedremo che cosa i vari stati e regioni hanno fatto con quali risultati e, comparando fra le differenti storie, cercheremo di dare un giudizio informato sulla validità delle varie scelte. Non parleremo direttamente dell’Italia (per questo c’è una eccellente “Pillola” tenuta da Paolo Spada), ma faremo spesso confronti con la situazione Italiana.

L'analisi che troverete in queste "pillole internazionali" sarà tutta basata sui dati disponibili, niente politica di parte, niente voli di fantasia, niente ipotesi complottiste, niente del genere.

Ovviamente, i dati da soli non bastano: vanno valutati e interpretati, e per questo occorrono modelli. Ma in ogni caso chiave del futuro sta nel passato, quindi è solo per mezzo di dati quantitativi che possiamo capire cosa è successo per poi valutare cosa succederà.

Cominciamo oggi con il caso più generale, quello del mondo intero. I dati li vedete nella figura in fondo a questo post (presa da "worldometer" (2)). Sono curve che rappresentano sia il numero di casi positivi giornalieri sia il numero dei decessi. Notate subito che la curva della mortalità mostra una chiara tendenza al declino mentre quella del numero dei casi non cresce da oltre un mese. Questo "stallo" dell'epidemia è stato notato recentemente anche all'organizzazione mondiale della sanità (OMS) (3).

Può darsi che troverete questo risultato sorprendente. In effetti, quasi tutti sono convinti che la pandemia stia ancora crescendo ovunque. Questa impressione viene probabilmente dal fatto che i media tendono a sparare il numero del giorno, senza preoccuparsi di valutarlo nel contesto della situazione generale. Un altro problema è che si sente dire spesso che l'epidemia tende a crescere "esponenzialmente" -- ovvero sempre più rapidamente. Ma questo non è assolutamente vero. Nessuna epidemia (come del resto nessun fenomeno fisico o biologico) cresce esponenzialmente se non nei suoi stadi iniziali. Tutte le epidemie seguono un ciclo dove la velocità di crescita aumenta all’inizio, ma poi rallenta gradualmente e alla fine comincia a calare.

E' quello che vediamo in tutti i casi storici e non è sorprendente che sia anche il caso della pandemia da covid-19. Nelle fasi iniziali, il virus trova molti facili bersagli negli esseri umani il cui sistema immunitario è impreparato a combatterlo. Così, si diffonde rapidamente. Col tempo, il numero di bersagli adatti diminuisce perché le persone già infettate sviluppano un certo grado di immunità. In certi casi, il virus stesso tende a mutare e a diventare meno letale. Il risultato è che il numero dei casi e dei decessi rallenta la sua crescita, raggiunge un massimo e comincia a calare. A lungo andare, l'epidemia sparisce: nessuna epidemia dura in eterno. A distanza di tempo, il ciclo può ricominciare con il virus che muta in nuove forme. Certe epidemie, come quelle dell’influenza, sono tipicamente stagionali. Si ripresentano tutti gli inverni (nell’emisfero Nord) per poi sparire in Estate (4).

In generale, i cicli epidemici tendono a seguire delle curve dette "a forma di campana". Sono descritte anche con nomi come logistiche, Gompertz, Bass, e altri. Più in generale, la teoria più comune che genera queste curve si chiama “SIR” dalle iniziali di “Suscettibili, Infetti, Recuperati” (5). Queste curve non sono mai esattamente simmetriche e in molti casi si vede più di un ciclo per via di vari fattori, ma la tendenza è quella.

Per molti paesi europei, la curva del ciclo epidemico è stata molto netta, mostrando una forma a campana leggermente asimmetrica con un massimo in Aprile. Da allora, la pandemia è stata in discesa in Europa. Negli ultimi tempi, alcuni paesi (inclusa l'Italia) stanno vedendo una risalita nel numero dei casi, che però non genera un corrispondente aumento della mortalità (2). In buona parte, questo è dovuto all'aumento del numero dei test che si fanno.

Per il mondo intero, invece, la curva non ha mostrato una curva a campana ben definita. Questo è dovuto a varie ragioni. Per prima cosa, c'è un fattore geografico. Il virus deve muoversi su grandi distanze da una regione del mondo all'altra e per questo ci vuole tempo. Poi ci sono fattori climatici: si sa che la diffusione dei virus che colpiscono l'apparato respiratorio avviene più facilmente in inverno (3, 6). Ci sono anche fattori casuali: qualcuno che si muove in aereo può portare rapidamente l’infezione anche a grandi distanze. Infine, ci sono fattori legati alle misure prese per evitare la diffusione del virus, lockdown, distanziamento, eccetera. Queste misure sono state prese in modo diverso in differenti stati e regioni e il loro impatto è difficile da quantificare.

Questi fattori spiegano la forma della curva planetaria della pandemia. Il virus si è diffuso prima in Cina, poi è arrivato in Europa. Poi ha attraversato l'Oceano, diffondendosi nell'America del Nord. Ancora più tardi, ha attraversato l'equatore. Nell’emisfero Sud, il ciclo epidemico è risultato sfasato di circa sei mesi in avanti, perché laggiù adesso è ancora inverno in termini meteorologici. Tutti questi salti da regione a regione hanno "slargato" la curva come risultato della sovrapposizione dei cicli nelle varie regioni.

Oggi, il virus non ha più territori vergini dove diffondersi. Rimane in crescita solo in certe regioni del Sud del mondo e in India, ma anche in quelle regioni l’epidemia mostra segni di una tendenza al rallentamento. Così, sembra probabile che la discesa nel numero dei decessi che vediamo sia il risultato della saturazione della popolazione infettabile. Insomma, buone notizie, la pandemia non è ancora finita ma sembrerebbe che abbiamo "scavallato" la fase peggiore. Ma ora che succede?

C’è chi si è addentrato in ardite previsioni a lungo termine basate sui modelli matematici (7). Si parla di un ritorno in forze dell’epidemia, di una “seconda ondata,” degli effetti di vari tipi di vaccini, e tante altre cose. Ma ci sono troppe variabili e troppe cose che non sappiamo per poter dire qualcosa di sensato oggi su cosa succederà nel 2021. Come hanno detto Andrea Saltelli e i suoi collaboratori in un bell’articolo su “Nature” (8) “I modelli matematici sono ottimi per esplorare le domande, ma pericolosi per sostenere di avere delle risposte.” Bisogna stare molto attenti con i modelli, perché dopo un po’ che uno ci lavora sopra rischia di convincersi che i modelli sono la realtà e questo porta a ogni sorta di errori e disastri (9, 10).

Per il momento, accontentiamoci di sapere che l’epidemia non cresce più e che sembra stia cominciando a calare. Per il futuro, ricordiamoci che le cellule viventi, di cui anche noi siamo composti, hanno convissuto con i virus per miliardi di anni (letteralmente!) (11) e che i virus non sono necessariamente patogeni o dannosi (12). Non aspettiamoci miracoli: dovremo continuare a convivere con loro, come abbiamo sempre fatto.

L’autore ringrazia Sara Gandini e Maurizio Rainisio per i loro commenti e suggerimenti su questo articolo.

Grafico da -- dati globali dei casi positivi e dei decessi da Covid-19. Immagine aggiornata al 3 Settembre 2020



Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)