Just as we really didn't (and don't) know much about how viruses are going to operate in our current human population, the current Covid pandemic may have many surprises left for us and they may be very unpleasant. Be clear, diseases rule the living world. Our immune system is amazing but it is in an ongoing arms race with diseases. Inevitably, some individuals lose a battle and that is called evolution. The question examined here is just how bad is that loss going to be for humans? The answer is not clear because there are a lot of variables, but there is some data and there are some interesting theories to work with.
As a note, my current work is about how inadequate and even problematic mother nature may be for human survival moving forward. She is pretty brutal and not at all sympathetic. Well, warning, this is a story about just how mean she can be and it talks about what could be quite the downer. My work is all about how humans can survive and thrive in the long term. We face some hard challenges but it could turn out great if we do the right things.
This all started for me in about 1978 when my high school biology teacher said that "there are tropical diseases out there that we never encounter and know nothing about". It was well known before then that humanity was continually going to face new problems as old diseases became changed by evolution and by encountering emergent new diseases. We are in an ancient arms race between diseases and our immune system. Now we have medicine in our arsenal but do not think that solves the problem. Diseases are very adaptive and can evolve in very short time periods in human terms. Disclaimer: I am not a medical professional, but then that is not what is needed here. As far as this is concerned, I qualify as an evolutionary biologist and human ecologist. I have been studying the problem since that time so I know a lot of the data and theories. Most of all though, I have long been thinking about this and how humans can prepare for the inevitable dangers of emergent diseases. I am very good at teasing out the meaning of probabilities in nature and that is what genetics is about, especially in the long term but I have always looked at this in the long term. Unfortunately, we might be there already.
One basic theory that you have probably heard is that when a new or evolved disease shows up, over time, it will evolve to be less fatal or damaging (less virulent) because if it were to kill the host immediately then it would limit its own spread. No one really knows, but there was some data from an experiment where a virus was released on an island off of Australia to control a plague of rabbits. It was assumed to be safe because of the isolation of the island, but it did eventually get carried to the mainland by flies. Diseases tend to be full of surprises. As expected it did become more contagious, but a surprise was that it did not become less virulent. It became far more deadly. The theory (afterward) was that there were so many rabbits that the disease could spread so fast that it did not matter if it killed the host. That is bad because there are an awful lot of human hosts and we travel a lot, potentially spreading any disease.
My usual study is about genetic and strategic adaptation to a new ecology to replace the hunter-gatherer ecology we left when we created the farms and cities of civilization. What we have called human progress, particularly the defeat of diseases by medical technology, has been the removal of natural selection. The problem with that is that every generation there are new or "de novo" mutations, broken genes that are mostly supposed to eventually be removed by natural selection. That means that we will develop a genetic load of broken genes, something no species can survive. All species need natural selection to keep their genetics "healthy". It turns out that the missing natural selection could ethically and economically be replaced by artificial selection. My book Genetics For A New Human Ecology is about that. Humans could husband their genes not only to remove broken genes like natural election does, but to actually ensure that the children got the best genes of both parents, something that nature does not and cannot do. That is great because everyone could have superior health, beauty, and brains. This is not at all about transhumans or superhumans. It is about healthy humans which are pretty super anyway and with our existing genetic variation we could become far more that we are now and adapt to the novel new ecology we are entering.
While that kind of artificial selection could help by giving individuals greater health with which to survive diseases, it would be limited in how much it could help the immune system. Nature has been focusing on that for a long time due to the incredible danger of diseases. Also, the genetics of our immune system are different than the rest of our genes. In ways, they actually correspond to diseases. So it will be hard to understand the genetics of the immune system let alone improve them much.
Most of my study was about that scenario of using artificial selection to replace the missing natural selection, because of the great danger of genetic load that we are actually already encountering. It is an issue of energetics in our ecology and humans require great resources for their long development period in our complicated society. A high mortality rate would be unsustainable. Because improving the genetics of the immune system would be difficult, artificial selection is unlikely to solve the problem of emergent disease any time soon except in the sense that more generally healthy people would be more likely to survive a disease.
As in the past, diseases are going to be some of the biggest challenges humans face in the future both because their danger and because if you use medicine to beat them, you have not beaten them. You have just held them off and the immune system is falling behind in the arms race.
So even though I did not focus a lot on diseases after figuring out about them leading to the danger of de novo mutations and genetic load, the principles are not hard to figure out or very obscure. For my purposes, I categorized diseases into three simple types: (1) common diseases that our immune system can widely handle, like common flu and colds. (2) Diseases that our immune system has problems with but can be managed by modern medicine such as flu, smallpox, measles, perhaps AIDs, etc. (3) Diseases that cannot be managed by modern medicine. In the worst case scenario it could kill off a major portion of humanity. Plagues used to do that. The trouble is that there are potentially many of those type 3 diseases and how do you decide which is which? What if AIDS had gone airborne? How much will medicine be able to help? The thing is that I didn't really expect to see a type 3 disease for at least 60 years and was hoping we would be ready for it by then, perhaps even based on my work I describe in my book in progress "Strategy For A New Human Ecology". It is about human survival strategies and so was supposed to include what it would take to survive a disease like that, because we are going to encounter it. The thing is that I am no longer sure about it being decades or centuries off. I was hoping we would have better strategies and medicine. That may just have been wishful thinking. A type 3 disease may be far closer than I thought and the only solutions will be genetic and moral, which we are not ready for. Why was my estimation wrong, if it is? It is just a probability evaluation, which I am good at. It is similar to earthquake forecasting on a known fault, that shakes at average intervals. Evolution and diseases should follow patterns. If I am wrong, why was my calculation wrong? Again, I do not know but I think we may know fairly soon. Covid is here and has shown a great ability to change to evade immune systems. Monkeypox is showing up such that it appears to be more contagious than it used to be. Researchers say it is rapidly evolving. Will it continue to become more contagious like Covid has? Are we just at the beginning of this? Again, we may know soon.
A gloomy theory to consider by Dr. Robert Trivers is that because of the long term problem of disease, all species are divided into natural disease resistant moieties. Some will have immunity to some diseases and some will have immunities to others. He said the diseases would evolve and occur cyclically, related to human potentials for fighting them off. We do not know enough to be sure one way or another, but it does fit patterns of how nature does commonly work, replacement. So then if a highly dangerous disease appears, only the moieties of individuals with resistance to that disease will survive. The death toll could be huge. It is not going to look like a great strategy of survival to humans because it means that one group is simply out of luck and will be replaced by the other in a cycle, but it is how nature works. The species survives the disease and that is what matters. The next time the disease evolves, a different group will be replaced, but again, the species and its genetic variation will go on. In ways, it is like human wars. So even if you could enhance genetic resistance to one disease, it is only one disease and you could not know what to plan for next. Not only would that not help with another disease but that very increased resistance to one disease might lower your resistance to another. Again, I consider potentials for genetic improvements humans can make, but the immune system is on another order of complexity from most of our genetic systems and it will be a long time before we really understand it much. Even if Dr. Triver's scenario is incorrect, it is perhaps a worst case scenario, we are still in trouble. A significant "population" could inevitably be wiped out by the disease. It would be many more people than it looks like is going to happen now. It just depends on the chance mutations.
To a greater or lesser extent, for the time being, we have no choice but to live with Covid. Some populations take more precautions and have far lower rates than other populations that do not take precautions, but it is so contagious that most people can expect to catch it at least once eventually. It usually is not fatal now. But, that may not be true in evolutionary terms and certainly would not be true without modern medicine. The evidence is growing that every time a person catches Covid there is damage to various systems of the body including the heart and neural system. The cumulative damage, in terms of evolutionary survival of the individual, could very well be fatal, especially because we do not know where the disease is going other than that it can evolve rapidly.
At the same time, monkeypox is a big unknown but could be an indicator of a different problem of disease. With a bit of determination and medical technology, monkeypox probably does not have to become endemic, but what if it does? We have often shown poor discipline in regards to Covid. Also there are many different populations on our planet with many different habits effecting disease transmission. Is monkeypox going to mutate? Theory suggests it will. What about the next disease? There will be one. Statistically speaking it will be a flu, but who knows? Unlike flus though which mutate at a fairly constant rate so some predictions can be made about them based on known data, Covid was a one off. No matter where it came from, its appearance is currently a one time event. We do though have some data on its mutation rate. That same reasoning though forces one to ask why has monkeypox shown up and that is what I have been leading to. As for one off events of emergent diseases, there will be more in the future.
Conclusion: we do not have enough information to know right now just where Covid is going or why monkeypox is becoming a problem. Analysis of data as it comes in will represent experimental testing of numerous known or yet to be developed theories. When the data correlates to any of the theories, in terms of science it will be considered proven. In terms of science, "proven" means it will be the main theory to be worked with until it is disproven or until another better explanation is developed. What is true about the disease now may change as the disease changes. I have two main thoughts on this. One is that we may be in more trouble from Covid than we think because it will mutate until it is more virulent and wipes out the susceptible moiety or just a lot of people. It has happened in the past. We just do not have the data but we will have it in a while. There is another theory I have to offer though because of the monkeypox. It seems like a surprising coincidence that it is showing up more commonly now. It may be population related though, including density, habits, and travel. The current world human population of over 8 billion people is completely unprecedented in terms of biology. It represents an incredible opportunity for diseases. It has often been asked if that many people can be fed or given water but that may not be the limitation. It may be that a population that big is just inevitably vulnerable to disease by offering just too much opportunity for mutation. I guess, if the deaths go over 100 million, genetic testing can verify or refute Dr. Triver's theory fits Covid.
After spending my life working for a human future where we are much more than animals, I fear such a tragedy as a disease could burn through civilization like fire through a forest full of ground fuel. Our best hope right now may be that medicine can stay ahead. Really though, if there is a disastrous disease or any of many other potential disasters that could damage or destroy human civilization, the last hope for humanity is moral. It is the will to struggle to survive and be more than a human animal in nature. At the dawn of our civilization, the Greeks could see that state of man in nature, just outside their city gates. It was much of the inspiration for their aspirations to be more than animals. It was their inspiration to struggle to make a civilization. If humanity holds onto those aspirations, we have all the tools we need to become something amazing that I have long envisioned and worked for.