I hadn't realised that animals were infected as well. It is also interesting to read the piece below, taken from 'The History of Human-Animal Interaction - The Medieval Period', which seems to take us back to where we began, with witches and cats!
Cats came under suspicion for a variety of reasons. Unlike dogs, they did not behave subserviently toward humans. This was considered unnatural, because it violated the biblical view that humans should have dominion over animals. Also, cats were very active at night .... Though cats had always behaved in this manner, to the superstitious minds of the Middle Ages, cats were practicing supernatural powers and witchcraft. Most accused witches were older peasant women who lived alone, often keeping cats as pets for companionship. This guilt by association meant that roughly a million cats were burned at the stake, along with their owners, on suspicion of being witches.
In the early thirteenth century Pope Gregory IX (1145–1241) declared that ... the devil had appeared in the form of a black cat. Cats became the official symbol of heresy.... Anyone who showed any compassion or feeling for a cat came under the church's suspicion. By the beginning of the fourteenth century, Europe's cat population had been severely depleted....
In 1347 the bubonic plague swept across Europe. Called the Black Death, it killed twenty-five million people (nearly a third of Europe's population) in only three years. Thousands of farm animals died as well, either from the plague or from lack of care..... In addition, millions of people are thought to have suffered from food poisoning during the Middle Ages because of the presence of rat droppings in the grain supply.
Centuries of cat slaughter had allowed the rodent population to surge out of control
