Epizoötic

Y. pestis is able to live in the dark, moist environment of rodent burrows even after the rodents have been killed by an epizoötic, or epidemic.

A fourth group, however, was very common — diseases transferred to humans from animal hosts, with animals acting either as intermediaries, as with malaria or typhus, or as primary or secondary epizoötic victims, as with bubonic plague.