epidemic

An epidemic is a disease that affects many people and it happens when a virus (such as covid), a bacterium (which can cause, for example, otitis) or even a parasitic insect (such as a louse), spreads through a village, a town or a country so rapidly that strong measures must be taken to stop it from spreading even more and infecting more people. One way to stop epidemics caused by a virus is by using masks, washing our hands frequently, keeping a safe distance and vaccinations.

When it spreads around the world, it becomes a pandemic.