the disease that made 'mad as a hatter' seem tame — dogs foaming, wolves gone wrong, empires unsettled.
means a highly contagious viral disease in dogs and other animals, and also an old word for civil unrest or an unbalanced mood.
from from latin dis- (apart) plus temperare (to mix properly) — literally a 'mixing-up' of the body's humors, borrowed by medieval medicine before it became a specific canine plague and, separately, a cheap water-based paint.
canine distemper virus — cdv, related to human measles, global in unvaccinated dogs
serengeti lion outbreak — 1994, distemper from village dogs killed 1,000+ lions
english civil war usage — 17th century writers called political chaos the body politic's distemper
distemper paint — chalk and glue mix used on frescoes for centuries