Which of the following definitions is incorrect?
a. Epidemic – fraction of the population having a disease at a specified time
b. Incidence – number of new cases of a disease
c. Pandemic – a disease that affects a large number of people in the world in a short time
d. Endemic – a disease that is constantly present in a population
e. Sporadic – a disease that affects a population occasionally
The Correct Answer and Explanation is :
The incorrect definition is:
a. Epidemic – fraction of the population having a disease at a specified time.
Explanation:
An epidemic refers to a sudden and widespread occurrence of a disease within a specific geographic area or population that is in excess of what is normally expected. It does not specifically refer to the fraction of the population affected at a given time. Rather, an epidemic is about the sudden rise in the number of cases, typically indicating that something has changed in the environment, behavior, or a pathogen’s ability to spread.
The correct definition of an epidemic is a widespread occurrence of an infectious disease in a community at a particular time. Epidemics typically focus on the increase in the number of cases of the disease rather than just a fixed fraction of the population.
Breakdown of the other terms:
- b. Incidence – number of new cases of a disease: This definition is correct. Incidence refers to the number of new cases of a disease that occur in a specified time period within a defined population. It measures how frequently a disease occurs within that population.
- c. Pandemic – a disease that affects a large number of people in the world in a short time: This is correct. A pandemic refers to an outbreak of a disease that occurs over a wide geographic area and affects a large portion of the global population. Pandemics often involve diseases that spread rapidly, such as the COVID-19 pandemic.
- d. Endemic – a disease that is constantly present in a population: This is also correct. An endemic disease is one that is regularly found and consistently present in a particular area or population. It can fluctuate in intensity but remains part of the normal health conditions for that population (e.g., malaria in certain regions).
- e. Sporadic – a disease that affects a population occasionally: This is correct. A sporadic disease occurs infrequently and irregularly, affecting individuals or small groups at isolated times. This pattern is different from the continuous or widespread nature of an epidemic.
In conclusion, the definition of “epidemic” in option (a) is the only one that is incorrect, as it misrepresents the concept of an epidemic by describing it as simply a fraction of the population having a disease.