In an outbreak of cholera in a village of 2000 population 20 cases have occured and 5 have died. Case fatality rate is
**Core Concept**
The case fatality rate (CFR) is a measure of the severity of a disease, calculated as the number of deaths among all reported cases. It is an important tool for assessing the impact of an outbreak and guiding public health interventions. In the context of cholera, CFR can vary depending on factors such as access to medical care, quality of care, and the virulence of the strain.
**Why the Correct Answer is Right**
To calculate CFR, we need to divide the number of deaths by the total number of reported cases. In this scenario, there were 5 deaths among 20 reported cases. By dividing 5 by 20, we get a CFR of 0.25 or 25%. This means that 25% of people who contracted cholera in this outbreak died from the disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the total number of reported cases. Without the denominator, we cannot accurately calculate the CFR.
**Option B:** This option is incorrect because it is a percentage value without a clear calculation. To determine the correct answer, we need to perform a calculation using the given numbers.
**Option C:** This option is incorrect because it represents a percentage value that does not match the calculation performed earlier (5 deaths / 20 cases = 0.25 or 25%).
**Clinical Pearl / High-Yield Fact**
When calculating CFR, it is essential to use the number of reported cases, not the number of suspected or probable cases. This ensures that the CFR accurately reflects the severity of the disease.
**Correct Answer: C. 25%**