There seems to be other theories similar to this, saying that our immune systems are subjected to too few pathogens in general, not just worms - due to the clea

There seems to be other theories similar to this, saying that our immune systems are subjected to too few pathogens in general, not just worms - due to the cleanliness of 'modern' life. There might even be some correlation to increased rates of allergy in countries that raised the living standard and less allergies among farmers (supposedly because they roll around in pigs shit? The reasoning is a bit unclear.) But I can't shake the feeling that there is something wrong with that theory. If you disregard large cities, 150 years ago, most people met very few people. Travelling was complicated and slow. Diseases was spreading of course, but decidedly in a slower pace than today - in most parts of the world. I'm fairly sure that an average person 150 years ago came in contact with less people in a year than I pass by on my daily commute. Heck, the building I work in has 3500 people in it, my kids go to three different schools with a couple of hundred other kids in each and their parents most likely works in other large workplaces, and I eat at restaurants that serves hundreds of meals every day. Is it not possible that an average person today are subjected to many -more- strains and variants of pathogens than ever. Maybe it is the increased load of _different_ pathogens that stresses the immune system? I mean, even if I moved in into the pigsty for good, it's just me and the pig there... The only way to catch a new disease would be from birds and rats, or a random mutation.