What is an epidemic - Ineqkill Atlas

What is an epidemic?

Some diseases are constantly present within a population. Their number may rise or decrease a little, but they remain at the “usual level”, they are what epidemiologist call ‘endemic’. Think of the flu, or a common cold.

An epidemic occurs when the number of people with the disease increases quickly and exceeds what would be expected in the population.

Epidemics can occur for various reasons:

the pathogen may have become more virulent;
the pathogen may have been introduced into a new area;
more people may have become exposed to it;
or the population may have become more vulnerable.

However, not all epidemics are alike. Let’s examine characteristics that are important from a public health perspective:

How severe is the disease?

The seriousness of a disease strongly shapes the response to it. Mild diseases, like a common cold, rarely justify a lot of effort in trying to prevent infection. But when a disease is highly dangerous or even deadly, it makes sense to go to great lengths to prevent people from catching it. For example, when an epidemic of Ebola hemorrhagic fever is identified, patients are very strictly isolated and medical staff use extreme personal protection equipment.

Is the disease developing fast or slow?

Diseases also differ in how rapidly they progress. The time between a person being infected and that person getting sick, also called incubation, can range from a few days to many years. Some infections, such as the flu and gastric flu develop and disappear quickly. Other infectious diseases evolve much more slowly. When infected people can transmit disease before any symptoms appear without being aware that they are infected, controlling the disease becomes far more more complicated. One such example is tuberculosis, or also HIV/AIDS.

Is the disease preventable?

Depending on how well we understand disease, we can potentially implement measures to prevent people from being infected (or passing the microbe on), from developing symptoms, or from dying. Historical experience shows that preventive measures can range from simple practices such as boiling or filtering water, to large-scale public health interventions including building water distribution infrastructure or implementing vaccination campaigns. Yet even simple measures may be challenging to implement because of living conditions or cultural context.

Is the Disease Treatable?

Throughout history, many diseases remained poorly understood and untreatable for long periods. For example, in various contexts, people diagnosed with leprosy were socially excluded or even considered dead as soon as they were diagnosed and sometimes exiled away from society. During the early years of the HIV/AIDS epidemic, in the 1980s, people with HIV/AIDS were considered “lost”, viewed as beyond help, because no effective treatment yet existed. As a result, even basic supportive care for symptoms was sometimes scant.