In what way did the bubonic plague spread

It spread on rats that carried flea's and other insect that carried the bacteria that was on ships going from place to place.

The bubonic plague spread through france and the UK through mainly 3 forms. The first would be spreading between people when they met or other reasons, the second would be when the bodies of the dead were burned and the tainted ashes would drift down and enter homes. The final known reason would be the fleas on rats that carried this disease and would bite people.