Today I was playing Alien: Isolation and saw a poster regarding lice and how you ought to get checked to reduce the risk of spreading it. (I give you this context to let you know that I am generally thinking towards the future, but my question is in regards to small spaces in the context of space travel and should be applicable today.) My thought initially was, "Well that's a good idea, disease, infection, viruses, and things like lice must be a big problem due to the isolated and cramped nature of space travel". But then I thought that perhaps that was also working in its favor. Might it be easier to control if fewer people were coming and going and it remained "contained"?
Looking at this answer, I can see that there are considerable precautions to eliminating infection aboard the ISS. I think this is smart because it is very expensive to bring supplies up and much cheaper to make sure your astronauts are healthy before they go.
We can see that outbreaks happen in close public places, like Disneyland but also in more common places like a house with several people inside. I think we've all experienced this at some point; someone in your family or house gets sick and it jumps from person to person and can take a long time to "get rid of".
This is my question: is a disease/virus/infection more hazardous in small spaces like the ISS or any other space vehicle, or does the isolation make it potentially easier to deal with? I'm not interested in the economic costs, because I think that it is rather obvious that is far more expensive to have an infected crew than a healthy one. I'm only interested in the potential risks to the health of the crew for current and future spaceflight.