Credit: CC0 Public Domain
Using evidence from the skeletons of about 70,000 ancient individuals, scientists at Flinders University have shown a pattern of co-evolution of humans and three major pathogens.
Biologist would interpret this as a typical evolutionary arms race, ending in a level of accommodation, as is predicted from the Theory of Evolution by Natural Selection.
Creationists, however, are obliged by dogma to interpret this as the work of a single designer, whom they have designated as 'intelligent' although there are precious few signs of any intelligence, or basic principles of good design for that matter. It is difficult to think of a suitable description of a designer who appears to be in competition with him/herself, constantly seeing the solution to the problem it created last as a problem to find a solution to next, but the terms 'intelligent' or 'designer' don't seem very appropriate or accurate.
What the researchers found is explained in the Flinders University press release:
Pathogens can either kill the human host or invade the host without causing death, ensuring their own survival, reproduction and spread. Tuberculosis, treponematoses and leprosy are widespread chronic infectious diseases where the host is not immediately killed.
Each of these three diseases shows a decline in prevalence resulting from co-adaptation that is mutually beneficial for the disease and human host. In the last 5000 years, before the advent of modern medicine, skeletal signs of tuberculosis become less common, skeletal manifestations of leprosy in Europe declined after the end of the Middle Ages, while skeletal signs of treponematoses in North America declined, especially in the last years before contact with invading Europeans.
From an evolutionary perspective, it makes sense for a pathogen to cause less harm to the host on which it depends for its survival so high levels of transmission appear to be a temporary evolutionary trait which reduces as time goes on when we look at leprosy, tuberculosis and syphilis.
Paleopathology is becoming an increasingly popular discipline which allows diseases which manifest on hard tissues to be studied in past populations because the diseases preserved for as long as the skeletal remains exist. Due to the preservation of pathological signs on skeletons, it is possible to trace the process of co-evolution of the three major infectious diseases as far back as specimens have been found.
Each of these three diseases shows a decline in prevalence resulting from co-adaptation that is mutually beneficial for the disease and human host. In the last 5000 years, before the advent of modern medicine, skeletal signs of tuberculosis become less common, skeletal manifestations of leprosy in Europe declined after the end of the Middle Ages, while skeletal signs of treponematoses in North America declined, especially in the last years before contact with invading Europeans.
Professor Maciej Henneberg, co-author
Anatomist and biological anthropologist
Anatomist and biological anthropologist
From an evolutionary perspective, it makes sense for a pathogen to cause less harm to the host on which it depends for its survival so high levels of transmission appear to be a temporary evolutionary trait which reduces as time goes on when we look at leprosy, tuberculosis and syphilis.
Paleopathology is becoming an increasingly popular discipline which allows diseases which manifest on hard tissues to be studied in past populations because the diseases preserved for as long as the skeletal remains exist. Due to the preservation of pathological signs on skeletons, it is possible to trace the process of co-evolution of the three major infectious diseases as far back as specimens have been found.
Dr Teghan Lucas, co-author
Flinders University
Flinders University
As Covid-19 impacts lives around the world- a new skeleton study is reconstructing ancient pandemics to assess human's evolutionary ability to fight off leprosy, tuberculosis and treponematoses with help from declining rates of transmission when the germs became widespread.
The researchers state the germs mutated to infect ancient humans so they could replicate- hopping across to as many new hosts as possible- but the severity of the diseases reduced as a result.
The analysis by Adjunct Professor in Archaeology Maciej Henneberg and Dr Teghan Lucas at Flinders University and Dr Kara Holloway-Kew at Deakin University published in PLOS ONE analysed data on about 70,000 ancient skeletons to reveal more about the spread of ancient infectious diseases by focusing on marks on bones as distinctive indicators of infection.
"Pathogens can either kill the human host or invade the host without causing death, ensuring their own survival, reproduction and spread. Tuberculosis, treponematoses and leprosy are widespread chronic infectious diseases where the host is not immediately killed," says Professor Henneberg, an internationally renowned anatomist and biological anthropologist.
Fig 1. Logarithmed frequency of skeletal signs of tuberculosis by date.
LOESS curve fitted with 95% of points included and tricube kernel.
LOESS curve fitted with 95% of points included and tricube kernel.
Fig 2. Logarithmed frequency of skeletal signs of treponematoses by date.
LOESS curve fitted with 70% of points included and tricube kernel. Frequency scale logarithmic.
LOESS curve fitted with 70% of points included and tricube kernel. Frequency scale logarithmic.
Fig 3. Frequency of skeletal signs of leprosy by date.
LOESS curve fitted with 60% of points included and tricube kernel.
LOESS curve fitted with 60% of points included and tricube kernel.
The three diseases are considered prime examples of co-evolution of human hosts and pathogens with records spanning across 200 generations.The teams findings were published open access today in PLOS ONE:
"Each of these three diseases shows a decline in prevalence resulting from co-adaptation that is mutually beneficial for the disease and human host. In the last 5000 years, before the advent of modern medicine, skeletal signs of tuberculosis become less common, skeletal manifestations of leprosy in Europe declined after the end of the Middle Ages, while skeletal signs of treponematoses in North America declined, especially in the last years before contact with invading Europeans."
Dr Teghan Lucas from Flinders University says this study highlights whether germs typically become more transmissible but less deadly over time so they can continue spreading.
"From an evolutionary perspective, it makes sense for a pathogen to cause less harm to the host on which it depends for its survival so high levels of transmission appear to be a temporary evolutionary trait which reduces as time goes on when we look at leprosy, tuberculosis and syphilis."
"Paleopathology is becoming an increasingly popular discipline which allows diseases which manifest on hard tissues to be studied in past populations because the diseases preserved for as long as the skeletal remains exist. Due to the preservation of pathological signs on skeletons, it is possible to trace the process of co-evolution of the three major infectious diseases as far back as specimens have been found."
Abstract
The key to evolution is reproduction. Pathogens can either kill the human host or can invade the host without causing death, thus ensuring their own survival, reproduction and spread. Tuberculosis, treponematoses and leprosy are widespread chronic infectious diseases whereby the host is not immediately killed. These diseases are examples of the co-evolution of host and pathogen. They can be well studied as the paleopathological record is extensive, spanning over 200 human generations. The paleopathology of each disease has been well documented in the form of published synthetic analyses recording each known case and case frequencies in the samples they were derived from. Here the data from these synthetic analyses were re-analysed to show changes in the prevalence of each disease over time. A total of 69,379 skeletons are included in this study. There was ultimately a decline in the prevalence of each disease over time, this decline was statistically significant (Chi-squared, p<0.001). A trend may start with the increase in the disease’s prevalence before the prevalence declines, in tuberculosis the decline is monotonic. Increase in skeletal changes resulting from the respective diseases appears in the initial period of host-disease contact, followed by a decline resulting from co-adaptation that is mutually beneficial for the disease (spread and maintenance of pathogen) and host (less pathological reactions to the infection). Eventually either the host may become immune or tolerant, or the pathogen tends to be commensalic rather than parasitic.
Henneberg M, Holloway-Kew K, Lucas T (2021)
Human major infections: Tuberculosis, treponematoses, leprosy—A paleopathological perspective of their evolution.
PLoS ONE 16(2): e0243687. doi: 10.1371/journal.pone.0243687
Copyright: © 2021 The authors. Published by PLOS
Open access Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
Human major infections: Tuberculosis, treponematoses, leprosy—A paleopathological perspective of their evolution.
PLoS ONE 16(2): e0243687. doi: 10.1371/journal.pone.0243687
Copyright: © 2021 The authors. Published by PLOSOpen access Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
In that respect both host and parasite have the same solution to the situation - minimal harm and so maximal reproduction.
But, in that case, why was the situation created in the first place? Creationists, of course have no sane answer to this paradox. Why would a designer create a situation that is immediately a problem for another of its creation, to be solved by tinkering with the design of the victim, only then to regard that redesign as a problem for the parasite, for which it now needs to be redesigned... and so on?
Of course, none of that makes any sense from a design point of view, intelligent or not and to describe it as intelligent design gives a whole new meaning to both terms. Malevolent, maybe, but not intelligent, and certainly bearing no resemblance to the supposedly all-loving deity of the Christian Bible.
Yet again, a piece of science, without the slightest effort or intent of the scientists, refutes the childish notion of intelligent design and exposes the whole thing as a hoax, relying on the scientific illiteracy and limited intellect of its target dupes.
In my popular book, The Unintelligent Designer: Refuting the Intelligent Design Hoax I have an entire chapter dealing with different arms races to be found in nature. Arms races are one of the strongest arguments against any intelligence or planning in evolution since they can only be the result of a process where one 'side' doesn't know what the other 'side' will do until it does it. There is no overall strategy in mind, such as we would expect of any designer who came up with the idea of host-parasite relationships in the first place - which is itself an absurd idea.
But Creationist dogma requires them to try to present these situations as the work of an omni-benevolent, intelligent deity, no matter how absurd that notion is ot how closely the reality make any such designer appear to be a pestilential, malevolent, sadist who enjoys watching its creation suffer.
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