In pre-industrial, pre-medical times, how often were people sick

I vaguely recall reading about Iraq when they were under sanctions, it mentioned something about how kids were sick 100+ days a year due to things like lack of sanitation and lack of clean drinking water. I guess if you were constantly exposed to polluted water and polluted food, you’d just get sick over and over and over.

So in agricultural societies with no medical care, how often were people sick? Did infections constantly run through the societies where people got sick and then recovered, or did people mostly not get sick but when they did, they died from it?

Do we know how often people were sick in pre-agricultural, hunter gatherer societies?

Define “sick”.

Certainly with hunter-gatherers internal parasites were downright common. Even in early agricultural societies they were common. They’re still common in some parts of the world.

Disease that are largely eliminated now, from tetanus to smallpox to all sorts of others that used to be common, particularly in cities, are now rare at least in the industrialized world.

Some of this (like the parasites) were chronic, some were transient like the colds we still experience, and some were more likely to kill you. So people were sick to one degree or another a lot (sometimes all of) the time.

Yes, large cities with inadequate sewer systems or poor water supply were disease vectors waiting to happen. Diseases (like bubonic plague starting in 1347) came in waves, as the previous survivors died off and herd immunity diminished. Other diseases were chronic. But in sparsely settled or hunter-gatherer societies, diseases rarely got the critical mass to keep going, nor was there the interaction to pass diseases to the next village or tribe.

That’s why I mentioned internal parasites - HG’s weren’t going to suffer from a crowd disease like measles because there wasn’t sufficient population density to sustain the disease, but they picked up parasites from eating things like game meat and drinking water contaminated with human and/or animal feces or snails (they carry a couple different sorts of parasites) or similar carriers. Would you consider intestinal worms a form of sickness? How debilitating an infestation depends on the individual’s ability to tolerate “passengers”, nutritional status, whether or not they were trying to fight something else off, and what sort of parasites there were (some are more debilitating than others). Some people carry a heavy load of parasites and don’t seem much affected. Others may suffer from anemia or worse.

I got a reminder about how fragile life was even in “industrial” times (around the turn of the 19th-20th centuries reading a couple of books about the period. William McKinley (later the President)'s wife was devastated by the death from typhoid by her little girl, and the death of an infant with an apparent birth defect (heart?) at a few weeks of age. The 5-year-old daughter of the commander of the British fleet in WWI came to see him off at the harbor with her mother, then was dead of a mastoid infection a few days later.

We take a lot for granted now.

In 1924, Calvin Coolidge’s 16-year-old son died of an infection that started from a blister on his toe.