How is control of a disease such as the bubonic plague complicated by the fact that it spreads across multiple animal species?

(can anyone also simplify the question so that i may understand what is being asked? )

slitherio is the original. its the best friend of all middle schoolers. the man you can count any time you have some free time. slitherio is the guy you hang with while you're in the computer lab suppose to be doing "research or whatever". slitherio isn't just a game but a friend.

wormaxio is just a fake trying to squeeze its way into the friend group. trying to pretend its cool and your best pal but how long has it really been there for you, really. it only wants you as friend to boost its social status. wormaxio is just annoying fake pleb. no offense

you and have a wonderful day

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.