How does the plague affect their animal carriers? Is there a difference between the effects on an insect like a flea and a mammal such as a rodent?
Fleas that acquire plague get blocked by the high numbers of bacteria, so when they bite a mammalian host the bacteria are regurgitated into the wound. The flea will die as it cannot absorb blood. Host animals (certain rodents) have lived so long with plague that they are not susceptible to it, but can pass it via flea bites to susceptible rodents and people.
