Scanning Electron Micrograph of a Flea. Fleas are known to carry a number of diseases that are transferable to human beings through their bites. Included in this infections is the plague, caused by the bacterium Yersinia pestis.

Adult male Oropsylla Montana flea, formerly known as Diamanus Montana.
This photograph depicts an adult male Oropsylla Montana flea, formerly known as Diamanus Montana.
Fleas are known to carry a number of diseases that are transferable to human beings through their bites. Included in this infections is the plague, caused by the bacterium Yersinia pestis.