What is the Difference Between Epidemic and Outbreak

The key difference between epidemic and outbreak is that an epidemic spreads on a bigger scale, whereas an outbreak spreads on a smaller scale and is unusual.

In an epidemic, the disease cases are more than the normally expected level, while an outbreak is usually localized. An outbreak can even involve a single case in a new area, and if it is not controlled, it can soon become an epidemic.

1. Overview and Key Difference
2. What is an Epidemic
3. What is an Outbreak
4. Epidemic vs Outbreak in Tabular Form
5. Summary – Epidemic vs Outbreak

What is an Epidemic?

An epidemic is the quick and unexpected spread of a disease that happens on a bigger scale over a larger geographical area. This affects a vast amount of people in a specific region, community, or population. It is usually an infectious disease that spreads rapidly to many people. Therefore, epidemics generally occur as a result of parasitic or infectious diseases such as meningococcal meningitis, typhoid, cholera, fever, and viral hemorrhagic. Smallpox, measles, polio, and West Nile fever are some other examples of epidemic diseases.

Generally, epidemics are not always contagious. There are three main reasons for the occurrence of an epidemic:

Strong bacteria or viruses
Bacteria or viruses introduced in a new place
Bacteria or viruses finding new ways to enter the human body

Types of Epidemics

Furthermore, there are two types of epidemics known as propagated and common-source.

Propagated epidemics occur when a disease is passed from person to person through direct contact, occur. Examples of direct contact include sharing items like needles or vehicles that help spread the disease; these are called vehicle-borne transmission. Meanwhile, if the disease spreads through vectors like mosquitoes, they are called vector-borne transmission. Ebola virus in Western Africa that spread through human contact mainly due to contaminated body fluids is an example.

Contrary to this, common-source epidemics, also referred to as point-source epidemics, occur when people get sick after being exposed to a bacteria, virus, or another infectious medium from the same source. For example, eating contaminated food from the same restaurant and getting unwell. Here, people get infected within a short period. In addition to this, common-source epidemics are continuous as well. In such cases, the epidemic may stretch for a longer period, for example, cholera.

Epidemics that are neither propagated nor common-source are vector-transmitted. They spread through vectors like mosquitoes and ticks. Lyme disease is an example.

How to Prevent Epidemics

Good sanitation and personal hygiene methods
Drinking clean water
Safe water storage methods
Disposing of human and animal waste properly

What is an Outbreak?

An outbreak is several people experiencing a similar illness due to a common exposure. This means a development in a specific infectious disease above what is generally expected. There are several categories of outbreaks, such as:

Waterborne Outbreaks

Several people experience the same illness after getting exposed to the same contaminated drinking or recreational water.

Foodborne Outbreaks

Several people experience the same illness after getting exposed to the same contaminated food source.

Non-waterborne and Non-foodborne Outbreaks

Several people experience the same illness, related by place and time. In such cases, the epidemiologist investigations put forward that transmission is due to a person-to-person transmission or a vehicle apart from water or food.

What is the Difference Between Epidemic and Outbreak?

An epidemic is an infectious disease that spreads quickly on a large scale and spreads in a large geographical area, while an outbreak is several people suffering from a disease due to a common exposure. The key difference between epidemic and outbreak is that epidemic is on a bigger scale, whereas an outbreak is on a smaller scale and is unusual.

The below infographic presents the differences between epidemic and outbreak in tabular form for side by side comparison.

Summary – Epidemic vs Outbreak

The key difference between epidemic and outbreak is that an epidemic is an infectious disease that spreads quickly on a large scale and spreads in a large geographical area, while an outbreak involves several people suffering from a disease due to a common exposure. If an outbreak is not controlled at the initial stage, it can easily turn into an epidemic.

Reference:

1. “Epidemic.” Wikipedia. Wikipedia.org
2. “Disease Outbreak.” Wikipedia. Wikipedia.org

Image Courtesy:

1. “2014 West Africa Ebola Epidemic – New Cases per Week” By Delphi234 – Own work, CC0) via Commons Wikimedia
2. “F-diagram-01” By UNICEF Philippines and Luis Gatmaitan / 2014 / Gilbert F. Lavides – (CC BY 2.0) via Commons Wikimedia

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