The bubonic plague was a bacterial disease that was spread through people who were bitten by fleas from rats. In the middle ages the bubonic plague was thought to have been the cause of millions of people dying. It was known as ‘ The black death’. Symptoms of the plague start with fever, swelling of the lymph nodes which can be found under the armpits, headache and bites on the body that turned red then black. Its a rare disease these days as fleas are now under control and we have less rat infestions.