Plague has always been one of the major diseases that has killed large numbers of people over the centuries. It struck the imagination with her deadly power and was perceived as a punishment of the gods or God. For Europeans living in the 14th-18th centuries, regular outbreaks of the plague were a frightening daily routine. The main factor of an epidemic or pandemic is that the disease constantly expands the territory of influence, going beyond the boundaries of one country. Moreover, it is difficult to stop or stop it, so more people are susceptible to the disease. The classical understanding of pandemics still implies that the disease is contagious – that is, it is transmitted from person to person or from animal to person by some infectious agent.
Bubonic is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, once in the human body, affects the lymphatic system. As a result of its reproduction, the lymph node becomes hard, a bubo appears on the body. In the late stage of the disease, inflamed lymph nodes can turn into open, festering wounds, and the plague can also spread through the blood to other organs.
New diseases arise for many reasons, one of which is the increased contact between humans and animals, which is due to the need to grow food for the growing population of the Earth. The carriers of the vast majority of pandemics initially circulated in animals and only then “spread” to humans. In addition, climate change, deforestation, swamp drainage and other anthropogenic activities are destroying the habitual habitats of many animal carriers of viruses potentially dangerous to humans.