What does endemic, pandemic and epidemic mean?

The coronavirus disease (COVID-19) has been spreading drastically from one country to another since December 2019. It has become one of the most rapidly spreading viruses in the world. The most uttered words nowadays are 'endemic', 'pandemic' and 'epidemic'. All three terms are epidemiological terms that are commonly used in the study of disease on human beings.

Endemic: The term endemic comes from the Greek word of 'Endemos' where 'En' means 'in or within' and 'demos' means 'people'. Hence endemic means 'in or within the people'. So the constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area is called endemic. The geographical area must be small and the disease must be happening in a time frame. COVID-19 was first identified in Wuhan city of China which was then called endemic disease.

Pandemic: The term pandemic comes from the Greek word of 'Pandemos'where 'pan' means 'all' and 'demos' means 'in people'. Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people. Presently the COVID-19 is spreading all over the world that is why the World Health Organisation (WHO) declared it as pandemic disease.

Epidemic: According to the Centres for Disease Control and Prevention (CDC), epidemic refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that particular area. As the COVID-19 cases increase rapidly in Bangladesh, it can be said that it is an epidemic disease. 

The writer is a student at the Department of Applied Nutrition and Food Technology, Faculty of Biological Science, Islamic University, Bangladesh.