Why did a large-scale plague appear in ancient society?

Plague in ancient society generally refers to infectious diseases such as cholera and influenza, and most of them broke out in a large area after huge natural disasters. Diseases caused by poor sanitation and a large increase of bacteria after natural disasters. There is a folk saying? There must be a great epidemic after a great disaster? In fact, there were many epidemics in ancient times. The ancients believed that epidemics did not occur at a fixed time, but could occur all year round, regardless of the climate. Another reason is eating wild animals. In ancient times when agriculture was less developed, food became scarce and people had to eat wild animals. Wild animals carry many viruses and bacteria, so they can't be eaten. And improper handling can also lead to illness, so large-scale epidemics often broke out in ancient times.

In ancient times when medical care was underdeveloped, how did human beings prevent and treat epidemics? As we all know, the body fluids and feces of patients with epidemic diseases will carry bacteria and viruses. Therefore, some people will choose isolation to avoid transmission after illness, and should be cremated immediately after death to avoid wider spread. In fact, many viruses don't kill people, but in that era of food shortage, most people didn't have enough to eat and wear, and their immunity was low. After being infected by the virus, there will be many complications before death. In this way, it is concluded that the people who survived the epidemic are all people with strong resistance. With the rapid development of science and technology, the epidemic will still break out. All we have to do is exercise, eat more fruits and vegetables to improve our immunity, and don't eat wild animals. The recent pneumonia has spread widely in COVID-19. But during the epidemic, don't believe in rumors, don't spread rumors, spread rumors, gather people or panic. Believe in doctors and countries. We believe that the sun will rise, the suffering will eventually pass, and the future will be beautiful and happy.