Typhus and cholera were prevalent in medeval winters where heating was curtailed.Could it be that typhus and cholera organisms are attracted to the only heat source available in winter — human body heat?
Horrible typhus outbreaks also occurred in London tenements and other cities back in Victorian times. And centuries before that.
Medieval people were constantly plagued with body lice and fleas.
Epidemic typhus, the type normally associated with wars and concentration camps, and transmitted by body lice, requires one to be squished up with other people who have typhus-bearing lice. Yes, the lice are attracted to your body warmth, but there have to be people with body lice bearing typhus in close proximity for you to catch it. That’s why outbreaks in the 20th century occurred in prisons, concentration camps, the trenches of WWI, where people were crowded together in unsanitary conditions and unable to bathe or delouse themselves.
I can’t imagine Holland having an epidemic just because people are turning down the heat.
Cholera is mostly water-borne. That’s why we worry about outbreaks after floods. Of course you can also get it from eating food contaminated with the bacteria. Why would the Dutch lose access to clean water just because they turn down their heat?
None of this makes sense to me.