Epidemic And Pandemic Diseases

What Is An Epidemic Disease?

Epidemic diseases are the diseases which are infectious and contagious. It is the spread of a disease in a particular region or area. It spreads when the infectious agent and the susceptible host are present in large numbers. An epidemic may be caused due to the following factors:

  • A recent increase in the amount.
  • The recent introduction of the agent in an area where it was never present before.
  • Enhanced mode of transmission, so that more people are susceptible to it.
  • Change in the host’s susceptibility to the agent.
  • Increased host exposure by the introduction of new portals of entry.

Types of Epidemic Diseases

The epidemic diseases are of three main types:

Point Source

It is the kind of epidemic in which all the cases are infected by a single source at the same time.

Continuous Source

An epidemic in which a causal agent such as contaminated water and the food is infecting people over a long period of time is known as the continuous source.


It is the type of epidemic in which the causative agent is transmitted from one person to the other allowing the epidemic to spread.

Examples of Epidemic Diseases

The Third Cholera (1852-1860)

Cholera is a water-borne disease that spread due to bacterial infections. The third cholera is the largest cholera outbreak known to the world. It originated in India and later on spread beyond the Indian boundaries.

The Asian Flu (1957)

It broke out in China and took the lives of one to two million people.

SARS (Severe Acute Respiratory Syndrome) (2003)

It is a respiratory tract illness caused by the coronavirus. It is believed to be transmitted from animals and took the lives of many people.

Ebola (2014)

It is a rarely occurring deadly virus that causes body ache, fever, and diarrhoea. It was transmitted from wild animals. It proved to be fatal for a large number of population.

HIV/AIDS (1960s-present)

This disease is believed to have spread from chimpanzees to humans in the 1920s. The virus attacks the immune system and reduces its efficiency. This disease is estimated to have taken the lives of 25 million people.

Extended reading: AIDS

What Is A Pandemic Disease?

A pandemic disease is an epidemic that has spread across a large area such as multiple continents or worldwide. HIV/AIDS is one of the most destructive pandemic diseases that broke out all over the world. Influenza is another pandemic disease and has occurred more than once. COVID-19 is another recent example. The pandemic is caused by a new infectious agent that has never caused a disease before. It has faced a larger death toll than the epidemic diseases. Antibiotic resistance and increased travel and mobility have increased the risk of diseases among humans.

Influenza Pandemic

A type of influenza virus known as the influenza A virus changed suddenly into a new virus that is different from all the existing viruses. This happens due to the change in the HA and NA proteins. When this new virus sub-type spreads among the people, it results in a pandemic.

Differences Between Epidemic And Pandemic Diseases

Listed below are a few differences

Epidemic Pandemic
The outbreak of the disease is limited to a particular region Disease outbursts across a wide geographical region affecting a huge population
Example – West African Ebola Example – Asian Influenza, HIV/AIDS, Cholera

Also read:

Difference Between Epidemic and Pandemic Disease
What Is An Example of A Bacterial Infection?
Infectious Diseases

Important Questions

Q.1. What is an outbreak?
A.1. An outbreak is declared in a particular region when multiple cases of a disease are observed or recorded.

Q.2. Can you give one example of a recent outbreak in India?
A.2. The Nipah virus outbreak in Kerala in the year 2018. COVID-19 is another example observed in recent times.

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  1. Thank you alot
    This is very helpful