
18. The plague
Most people think of the plague as an epidemic that occurred in the 13th century which wiped out a third of Europe’s population. Known as the Black Death, there was no cure for the plague. Bubonic plague came to Europe in the fleas of the rats that inhabited the ships traveling the world.

The bacteria Yersinia pestis still lives in the fleas on the bodies of rodents. A bite of one of these fleas can make a human very ill. It’s possible for a cat to acquire the bacteria if it hunts a rodent that carries the flea. For pets, the plague makes them experience fever, swollen lymph nodes, and inflammation. A pet owner who contracts the plague will have a sudden onset of fever, headaches, weakness, and swelling of lymph nodes. The incidences of plague are very few. Today, the disease can be treated with antibiotics for both humans and animals.