An epidemic refers to an infectious disease that can infect a large number of people. Infectious diseases that can spread widely in a short time, such as influenza, meningitis, cholera, etc. Universal social ills. An epidemic can only occur in a certain area, or it may be a global epidemic. In European languages, the etymology comes from Greek. When the observed value of a disease exceeds the expected value, it is called an epidemic. A global epidemic is defined as the spread of diseases across continents.

Chinese name

epidemic

Foreign name

epidemic

pressure

Diseases that can infect a large number of people

spell

Liuwu xínɡ bìnɡ n ɡ

epidemic

Swine flu, SARS, bird flu.

Epidemics:

Liuwu xínɡ bìnɡ n ɡ

(1) Infectious diseases that can spread widely in a short time, such as influenza, meningitis, cholera, etc.

(2) metaphor ubiquitous social ills.

Principles and principles

Whether the continuous occurrence of an infectious disease can be defined as an epidemic, that is, an epidemic in a narrow sense, is not the main determinant; But the speed at which the disease spreads. If each infected person spreads the disease to more than one person, the overall infected population will increase exponentially, and this infectious disease is an epidemic. So even if only a few people are infected with an infectious disease, it can still be called an outbreak.

When infectious diseases are prevalent:

R0 is the basic infection number of this disease, and S is the possible infection rate in the population. This is the mathematical model of epidemic definition.

Examples of epidemic diseases in history are: the Black Death (plague) in medieval Europe, the Spanish flu that broke out in World War I, and AIDS in recent years.