I’ve always found it interesting to note that while the list of infectious diseases in humans [1] is long, it isn’t that long.
[1] https://en.m.wikipedia.org/wiki/List_of_infectious_diseases
[1] https://en.m.wikipedia.org/wiki/List_of_infectious_diseases
https://en.wikipedia.org/wiki/Prion#Diseases
https://en.wikipedia.org/wiki/Balamuthia_mandrillaris
https://en.wikipedia.org/wiki/Pseudomonas_aeruginosa
https://en.wikipedia.org/wiki/Macacine_alphaherpesvirus_1
https://en.wikipedia.org/wiki/Baylisascaris_procyonis
https://en.wikipedia.org/wiki/Orthohantavirus
Some of them we have no idea how to treat. Prions are 100% deadly.