Fungal
infection of brain tissue (Wikicommons, CDC). Some fungi persist in the human
brain for years and begin to harm their host only in old age. What were they
doing previously?
I've
published a paper on manipulation of human behavior by fungal pathogens. Here's the abstract:
Many
pathogens, especially fungi, have evolved the capacity to manipulate host
behavior, usually to improve their chances of spreading to other hosts. Such
manipulation is difficult to observe in long-lived hosts, like humans. First,
much time may separate cause from effect in the case of an infection that
develops over a human life span. Second, the host-pathogen relationship may
initially be commensal: the host becomes a vector for infection of other
humans, and in exchange the pathogen remains discreet and does as little harm
as possible. Commensalism breaks down with increasing age because the host is
no longer a useful vector, being less socially active and at higher risk of
death. Certain neurodegenerative diseases may therefore be the terminal stage
of a longer-lasting relationship in which the host helps the pathogen infect
other hosts, largely via sexual relations. Strains from the Candida genus are
particularly suspect. Such pathogens seem to have co-evolved not only with
their host population but also with the local social environment. Different
social environments may have thus favored different pathogenic strategies for
manipulation of human behavior.
Please
feel free to comment.
Reference
Frost, P. (2020). Are Fungal Pathogens Manipulating Human Behavior? Perspectives in Biology and Medicine 63(4): 591-601. https://doi.org/10.1353/pbm.2020.0059
12 comments:
"Your honor, I plead innocent to the charge of murder. The fungi made me do it!" 😆
Microbes are predominantly parasites i.e. they extract energy from the host and may contribute some value, accent on may. The exact balance is not examined (as far as I can see) for some reason. It may not be measurable or perhaps there is a bias towards seeing mutualism.
The lack of investigation intrigues me. As an observation but not a logical argument I have noticed that my "woke" friends so not even wish to consider the possibilities. These friends hols advanced degrees in the life disciplines.
I am interested in hearing views from others.
Chris,
Your (implicit) argument is that any effort to find causation will undermine the idea of "free will" and that, therefore, we will be held less accountable for our actions.
That kind of argument is silly. Everything has a cause. The fact that my actions have a cause outside myself doesn't make me less accountable for what I do.
Morris,
Investigation is biased toward infections that produce life-threatening effects over a short time. If the effects occur over a longer time, and are less life-threatening, they attract less interest from medical researchers.
I am surprised that you would execute insane people for murder. It has long been a legal principle that the causal factors behind a person's actions must be taken into account in assessing the criminal content of those actions.
One other thing: people on the Internet have been using these things called "emojis" to provide emotional context to their comments. The 'emoji' that I used here indicates that the comment is intended to be humorous -- that the comment is flippant.
@Peter
I see your point as being more or less self evident. My concern is with longer term effects such as aging and parasites. The bizarre effects of parasites on "lesser" animals e.g. insects is widely reported in research but the possibility of something similar in humans is not even considered.
My bias is that widespread bias exists for unrealistic mutualism. But what is the benefit apart from seeming to be altruistic?
Bump
You have raised a tantalizing notion but you stop short of going the whole way which to my mind is the nature of the internal eco system in the human animal.The possibility that microbes ultimately invade most human cells by advanced age is not fantastical yet research in that area is carefully avoided.
Chris,
I am personally opposed to capital punishment, largely because of the risk that it may be used for political reasons. I can understand capital punishment in a situation where there has been a breakdown of law and order. In that case, it would be analogous to wartime execution of spies.
Morris,
The benefit for the pathogen is that the host remains capable of propagating copies of itself to new hosts. As for the benefit for the host, it gets a stay of execution. In some cases, it can move into new social niches.
If people are disinhibited because of cultural permissiveness or even certain types of dementia, they are going to have generalised promiscuity in their sexual relations. However if a pathogen's life cycle in humans required a certain type of non procreative sexual activity then that particular type of sexual act would become disproportionately, indeed peculiarly, more common as the pathogen spread.
@Peter Frost,
How do you believe society should genetically pacify it's population?
Has greater access to birth control sufficiently decreased the amount of certain individuals procreating?
Yes, I am thinking of how this applies to helping immigrant populations that have already been let in "assimilate".
Sean,
This may be why many religions, notably Islam, emphasize regular washing of hands and the genitals. There may have been a half-conscious understanding of pathogenic transmission.
Anon,
In modern societies, fertility rates are falling below the replacement level. Consequently, there will be a need for measures to raise the fertility rate, and such measures could be aimed preferentially at stable married couples who have not committed violent crimes.
At the risk of becoming really tedious I am not getting my main point across at all.That point: diseases (so called) of old age are caused by microbes is a viable hypothesis supported by empirical findings yet that investigation is carefully avoided. More than avoided but opposed by observationally unsupported hypotheses for altruism and mutualism. So is this due to some 'me too' delusion (mass scale of not telling the truth) or maybe microbial infection effects?
If you think this line of thought is crackpot please say so.
"NEW research has shown another interesting fact - people with fewer teeth in their sixties have more chance of having Alzheimer’s. [...] Also - and this is most interesting - it has been shown that the brain of Alzheimer’s patients contain p gingivalis and residual genetic material from this bacteria. Specifically, this has been found in the hippocampus, which is important for memory and where memory loss is a crucial syndrome of Alzheimer’s, and it has been found in the cerebral cortex, a region involved in conceptual thinking, whose loss is another syndrome of Alzheimer’s. [..]Now, p gingivalis is known to release a set of neuron-destroying enzymes called gingipains, which have been found in Alzheimer’s patient brains. One, these gingipains could directly destroy neurons. Two, amyloid plaque, formed in the brain as a way to contain the p gingivalis infection, may destroy neurons or neuronal transmission. Three, an immune response to the bacteria, causing inflammation, may destroy neurons."
"IN al-Mahasin: From Muhammad al-Halabi from Abi ‘Abdillah (as) who said: The Holy Prophet (S) used to brush his teeth a lot."
Post a Comment