original: A pestilence is any virulent and highly infectious disease that can cause an epidemic or even a pandemic.
simplifications: A pestilence is a highly infectious virus that can cause an epidemic or pandemic. A pestilence is a toxic and very infectious disease that causes an outbreak or even a widespread outbreak. A pestilence is a disease that can cause an epidemic or even a pandemic. A pestilence is a virus and disease that can cause an epidemic or pandemic. A pestilence is any virus or highly infectious disease. They can cause an epidemic or even a pandemic. A pestilence is any virulent, very infectious disease that can cause an epidemic or pandemic. A pestilence is any harmful and highly infectious disease that can cause a mass outbreak, A plague is any deadly, very catching disease that causes an widespread outbreak. Severe and very contagious disease that can rapidly spread is called a pestilence. A plague is any virulent and highly infectious disease that could lead to an outbreak, or even a  widespread