Creatures
Fleas bite humans infecting them with the
plague. The fleas live on rats. Rats live on waste left about by humans.
Leeches
The leech (worm-like creature) was used extensively in medicine up until
quite recent times. It sucks blood and would have been used to try and
reduce the swellings caused by the plague. It was also thought cutting
a vein and drawing some' bad blood' (bleeding a patient) was a sound medical
technique.
Types of Plague
There are two types of plague - bubonic caused by the bites of fleas and
resulting in large tumours, or buboes, and pulmonary plague transmitted
by breath.
Most plagues were of the bubonic variety. The fleas were brought to England on the backs of black rats which stowed away on ships. They originally came from India.
Discovery of Cause
It was thought the plague was caused by bad smells. Rats were suspected
but the part of the flea was not realised until 1914!