I have held the theory for many years that the current state of auto-immune problems growing epidemic is due to modern living which suffers both from lack of significant exposure to immune challenges as well as a lack of complex phyto-nutrients and micro-flora (well before pro-biotics and pre-biotics entered the common advertising sphere) but I would have a hard time signing on to the taking on some of the parasites mentioned which are not traditionally considered symbiotic. Granted, there may be some complex interplay between their presence and many of the other internal-flora and ecology of the biochemistry that results, but don’t ask me to guinnea pig those experiments
I have long thought this to be true. We live in such a sterilized society (though not as sterile as some people want to believe)
Also, the huge increase in things characterized as mental disorders. Of course, they removed Homosexuality and Transgenderism, but the influx has been likely far greater.