My mother was an infectious disease nurse just prior to and during World War 2 in England. I have talked to her quite a bit about this and was surprised at how effective their methods were. While the cures were not up to modern standards, they were very good at preventing the spread of the diseases once they were identified.
I have one of her old nursing books dated 1940, that covers how to treat a infected patient at home. This was used for disease like scarlet fever, diphtheria, whooping cough, typhus, smallpox, polio and tuberculosis. She nursed all of the above without getting sick. The methods they used may seem a bit on the extreme side to us with modern medicine, but remember they had no antibiotics.
Some of the terminology is a little old, so you may have to study it a little. Phenol is probably the oldest known disinfectant, when it was called carbolic acid. This is also poisonous if taken internally and at full strength can cause skin burns. If you intend to use carbolic acid learn about it first, because it can be dangerous. I will post more from the old books soon.