Theflea (Siphonaptera) is aninsect which lives on manyanimals and sometimeshumans. Fleas areectoparasites and drink theblood of the animal they bite.
Fleas live outdoors in sand or tallgrass, and jump to any passing animal and layeggs. Flea bites are usually red bumps and they itch.
There are many species of flea such as dog fleas, cat fleas, human fleas, northern rat fleas, and the oriental rat flea. During the Middle Ages, the oriental rat flea spread a bacteria that caused thebubonic plague, also known as the Black Death or Black Plague. This was a hugeepidemic much more severe than today'sbird flu. The oriental rat flea was infected by the bacteriaYersinia pestis.
