What were the causes of plague in 1665 ?

In 1665 there had been a very hot summer, and the population of europe was growing hugely. This was causing more rubbish and food waste, Attracting flea ridden rats. with the hot rubbish it made a perfect place for rats to breed. The fleas on these rats carried the deadly plague disease. If a flea made its way onto your skin, its bite would transfer the bacteria into your bloodstream. infecting you with the bubonic plague.

The true cause of the plague was discovered 200 years after this outbreak. Before this, they had some very weird beliefs.