Final answer:
An epidemic is a sudden and widespread outbreak of a disease that affects a large number of individuals in a population at the same time. A pandemic is an epidemic that spreads across multiple populations or even worldwide. An endemic disease is one that is constantly present, usually at a low incidence, in a population.
Step-by-step explanation:
A sudden and widespread outbreak of a disease, such as the cholera outbreak in Mr. Tseng's village, is called an epidemic. An epidemic occurs when a disease affects a large number of individuals in a population at the same time.
On the other hand, a pandemic is an epidemic that spreads across multiple populations or even worldwide.
An endemic disease is one that is constantly present, usually at a low incidence, in a population.