When it comes to infectious diseases, the words endemic, epidemic or pandemic keep appearing. But what does the term actually mean and what is the difference?
No two infectious diseases are the same. Some diseases have only very mild symptoms, other diseases cannot be treated or are very difficult to treat and still others have a very high mortality rate. There are also diseases that are extremely rare or only occur in certain regions of the world. Still other diseases are highly contagious and spread like wildfire around the globe while there are also diseases that have already been eradicated and some that keep coming back. If you take a look at Ebola, HIV, the flu or the coronavirus, which spread throughout the world at the end of 2019 / beginning of 2020, the differences between the diseases become quickly and clearly visible. In the course of certain diseases, the terminology appears again and againEndemic , epidemic or pandemic , but what do they actually mean and how do they differ?
Endemic is a permanent threat
An infectious disease is known as endemic if it occurs regularly in certain regions. It is typical of endemics that the number of infected people remains relatively constant over time. Although people keep getting infected, the total number of people infected does not increase.
A typical example of an endemic disease is malaria. Every year around 300 million people are infected with the so-called intermittent fever – mainly in tropical regions.
From today’s perspective, it is highly unlikely that an endemic infectious disease will one day be eradicated. Humanity has to live with this disease and can only develop better drugs to treat it.
An epidemic is regionally limited
One speaks of an epidemic or an epidemic disease if it occurs unusually frequently in a region in a limited period of time. If the number of infections in an area rises above the normal expected level, it is often referred to as an outbreak .
The cause of an epidemic is often a change in a pathogen. For example, if a virus mutates, it can be significantly more contagious. However, the introduction of a new disease into an area can also lead to an epidemic.
A classic example of an epidemic infectious disease is smallpox, which was introduced to America by Europeans at the beginning of the 16th century. According to the latest estimates, up to 90 percent of America’s indigenous population fell victim to this infectious disease.
A pandemic is spreading across country and continent borders
A pandemic or a pandemic disease is not regionally limited but spreads globally, whereby even with a pandemic there may be areas that remain unaffected by the disease (often smaller islands).
Examples of a pandemic is the Spanish flu, which between 25 and 50 million people died. The swine flu in 2009 and the coronavirus in late 2019 / early 2020 are also pandemic diseases.
However, a pandemic does not necessarily have to be accompanied by a high mortality rate. The definition is only about the global spread of an infectious disease over a certain period of time.