Public health system 1. Epidemic Degree of Disease Epidemic Degree of Disease is the observation of the number of specific diseases, and the relationship between cases in a certain ethnic group over a period of time. In general, the intensity of a disease epidemic can be divided into endemic, epidemic, and pandemic. Endemic The term endemic refers to the persistent presence and/or widespread prevalence of a disease or an infectious agent in a population within a geographic area. For example, chickenpox is considered endemic in the UK, but malaria is not. High prevalence refers to persistently high levels of disease prevalence in specific places. Epidemic As explained by the World Health Organization, an epidemic is a regional outbreak of a disease whose transmission is abnormal. It refers to an increase (usually sudden) in the number of disease cases that exceed the normally expected level of the population in the area. By definition, the term “outbreak” has the same meaning as an epidemic, but is usually used in a wider geographical area. On the other hand, “clustering” refers to a summary of suspected cases larger than expected, grouped by location and time. Pandemic A pandemic is an epidemic that has spread to various countries and continents-the global spread of a new disease. The flooding is not an easy or careless word, warned Tedros Adhanom Ghebreyesus, director-general of the WHO. He claimed that the term was previously avoided by global health agencies. Because he didn’t want to give the impression that the coronavirus is unstoppable or uncontrollable. Why COVID-19 is now called a pandemic? After 118,000 COVID-19 positive cases in 114 countries, it became clear that the virus had exceeded the definition of an epidemic. The disease is generally considered a pandemic when the causative factor of the disease is different from the virus strains currently circulating in humans and has the ability to infect humans. Coronavirus has spread rapidly, and no vaccine or treatment has been formally discovered. Therefore, WHO had to declare a global epidemic as a curb to its spread.