A disease is any disturbance or anomaly in the normal functioning of the body that probably has a specific cause and identifiable symptoms.

Diseases are one of the factors threatening us from having a properly functional life. Throughout our history, epidemics have caused the extinction of whole populations. Over the last century, man has discovered many microorganisms that cause diseases in humans and animals, and has learned how to protect himself from them, by either prevention or treatment.

What Is an Epidemic?
An epidemic is generally a widespread disease that affects many individuals in a population
It is spread rapidly and extensively by infection and simultaneously affects many individuals in a particular area or population.
An epidemic may be restricted to one location or may be global (pandemic). An outbreak of a disease is defined as being epidemic, however, not by how many members or what proportion of the population it infects, but by how fast it spreads