If bitten by an infected flea, a person usually develops a bubonic form of plague, which is characterised by a swelling of the draining lymph node.

• 假若人类被受感染的跳蚤叮咬，被叮位置的淋巴结会肿胀起来形成淋巴腺鼠疫，是最常见的鼠疫。另外，败血症型鼠疫是细菌直接经血液中扩散所致；