Fleas (order Siphonaptera) are obligate blood-feeding ectoparasites on mammals and birds. Both adult males and females feed on blood using piercing-sucking mouthparts. They are important vectors of disease — the rat flea (Xenopsylla cheopis) transmits Yersinia pestis (plague) and Rickettsia typhi (murine typhus). Flea larvae, however, feed on organic debris including adult flea faeces (dried blood).