Which term describes a disease pattern that is continuously present in a population at a steady rate?

• A. Sporadic
• B. Outbreak
• C. Epidemic
• D. Endemic

Answer: (D)

Endemic describes a disease that is continuously present in a population at a steady rate. It reflects a baseline level of transmission that stays relatively constant over time, even though there may be seasonal fluctuations. This differs from sporadic cases, which occur irregularly and infrequently; an outbreak, which is a sudden rise in cases in a limited area or group; and an epidemic, which is a broader, more widespread increase in cases beyond what’s normally expected. Conceptually, endemic patterns show persistent, ongoing presence rather than the irregular or dramatic spikes seen with the other patterns. For example, a disease that maintains a steady, year-after-year incidence in a region demonstrates an endemic pattern.