Say that an individual with a decent, but not mastery level, understanding of health, medicine, and sanitation were to travel to an era with technological level roughly around medieval to Renaissance levels.
Lets say this individual is able to get people to listen to him sufficiently to enact policy based off of his suggestions. I'm wondering how much disease can be minimized or removed simply from understanding of sanitation and how diseases spread. I do not want to look at more difficult medical intention like developing vaccines/antibiotics or knowing specifics of any one dangerous disease, only the more generalized knowledge. So I'm looking at things like:
- Boiling water to kill bacteria before using it for medical procedures (or even drinking it for those with weakened immune systems).
- Using boiled water to clean hands and instruments before medical procedures
- keeping urine and feces from being dumped straight into the river people drink from
- Knowledge of how diseases spread leading to suggestions like use of face mask, teaching people to cover sneezes up, avoiding physical contact with ill, and sanitizing or destroying things which came into contact with ill's bodily fluids
- Modern quarantine methodologies.
- Scientific approach to identifying which method an illness spreads by and attempts to focus treatment and quarantine to those methods it spreads. Including disposing of animals that may spread disease like black plague.
- safe disposal of diseased bodies.
- Removing of blatantly wrong medical presumptions that may be harmful.
Assuming these ideas are spread by this individual I'm trying to determine how much disease and illness may be prevented. I'm looking at general illness/death to common diseases primarily, but also somewhat interested in usefulness for treating a specific epidemic that may currently be ongoing.
My problem is I don't have a sense of scale as to what approaches were already known by a given period in time, and which were still foreign. Thus I'm trying to determine how effective these were and how much these would likely already be done.
In theory I don't want to limit this to time-travel, but any situation where modern knowledge meets a group of roughly the technological level I mentioned, even if it were some planet with a new sapience, some parallel universe with alternate history, or a magical portal to a different realm. I realize without the scope of an exact time period it's harder to say, but my point is I'm curious as to what would be expected to be known given this rough technological level, NOT what a specific country may have known.