Which statement distinguishes endemic from epidemic?

• A. Endemic refers to a constant presence in a population; epidemic is an unusual outbreak larger than expected
• B. Endemic refers to a constant presence in a population; epidemic refers to a rapid, global outbreak
• C. Endemic refers to a rapid, global spread; epidemic refers to constant presence
• D. Endemic refers to no cases in a region; epidemic refers to new cases

Answer: (B)

The main idea is to contrast a stable baseline with an outbreak above that baseline. Endemic means a disease is consistently present in a population at a relatively steady level, forming the usual background of cases. An epidemic, on the other hand, is characterized by a sudden, unusually high number of cases that exceeds what we would expect based on the baseline—an outbreak that stands out from the norm. The phrasing in the option captures this distinction by linking endemic to constant presence and epidemic to an unusual, larger-than-expected rise in cases. Remember that epidemics can be regional or, if they spread widely, become pandemics, but the defining feature is surpassing the normal level of cases, not just geography.