The thing I'm talking about is diseases in the last half of the nineteenth century. Doc Halliday had tuberculosis and everyone knows it, showing up nearly every time his name is mentioned in a book. But there were several other illnesses that are barely mentioned, excluding TB, small pox, and cholera. Small pox appears regularly in the journals and diaries of travelers heading west, especially during the Great Migration. Cholera is mentioned in many of these journals, too.
One of the worst plagues on the children of the western settlers was diphtheria and along with that scarlatina or scarlet fever. Both these plagues killed many children. And then there were typhoid fever and whooping cough. No cures were available for these illnesses until after the turn of the century or just before. When I was growing up in the 1930's, there was dipththeria in the neighborhood and my mother was always telling me about typhoid fever that could be caught from drinking out of contaminated streams, one of our main sources of water. The 1918 typhoid epidemic ravaged our little town, killing many of the young residents. Scarlet fever was around in the 1940's, but I didn't hear much of it in the 1950's and -60's.
There are a few novels where one of these sicknesses is mentioned, but it didn't seem to be a very popular subject for inclusion in the stories people wrote back then or now for that matter. I'm just guessing but TV shows like Little House on the Prairie had episodes where some kid was dying from one of these diseases and someone was sent for a doctor who showed up just in time to save the patient.
I haven't read anything recently where illness makes up part of a story in a Western, unless it's TB (consumption). I'm not saying that there should be more of it, but that these diseases killed a lot of kids and grownups and maybe could have been included in more stories to make a more complete picture of social and family life. Maybe it's just too gruesome a subject to consider.