Question

What was the incidence rate of cola colic for 2017 (per 100) from the scenario below?

Problem: Leopoldville is a village of 500 elves with two major ethnic groups—the Anorexies, who comprise 60% of the population, and the Pigouts, who constitute the remaining 40%. The folks of Leopoldville suffered from a variety of maladies, especially donutitis. In 2012, the prevalence rate for this painful disease was 50/1,000 people. Unfortunately, there was a severe outbreak of donutitis in 2013 with the people developing 125 new cases. Just when the problem was under control (only 50 new cases of donutitis in 2014), the townspeople hit a streak of bad luck and were overcome by an epidemic of cookienemia. Although 100 cases of this dreadful condition were reported during 2015, citizens who had previously contracted donutitis were totally resistant and not at risk (lucky for them). Responding rapidly to the emergency, the local health department commenced an intense immunization program which had a tremendously positive impact – only 5 new cases of cookienemia developed during 2016 (3 in Anorexies and 2 in Pigouts). The whole town celebrated, especially the Pigouts, who soon thereafter showed an increased risk of cola colic, developing 50 cases during 2017. Fortunately for the Anorexies, cola colic is confined to Pigouts. Unfortunately for the Pigouts, other diseases afford no protection against cola colic. Assuming there were no deaths births, cures, or migration in Leopoldville from 2012-2017.

Answer 1

Incidence rate : it is defined as the number of new cases occuring in a defined population during a specified time period, it is number of new cases of specific disease during a given time period population at risk during that period X 1000, prevalence =incidence x duration of disease, and it is also know as incidence density or force of morbidty and expressed as number of new cases per person time at risk and the person time can be person days, personmonth, person years but more common is per 100 person years , so incidence rate is :50(new cases)/200( the population of pigouts 40% of 500)x1000=2.5.