What term describes the ratio of people who ate a specific food and became ill to all people who ate that food?

• A. Food-specific attack rate
• B. Secondary attack rate
• C. Case fatality rate
• D. Overall attack rate

Answer: (A)

The term describes the risk of illness from a specific exposure by looking only at those who were exposed to that exposure. It is the proportion of people who ate the food and became ill divided by all people who ate that food. For example, if 20 people ate a particular dish and 5 became ill, the food-specific attack rate is 5 divided by 20, or 25%. This measure helps investigators assess whether a particular food item is linked to illness.

Secondary attack rate looks at how the disease spreads among susceptible contacts of cases, not at a specific food exposure. Case fatality rate is the proportion of cases that result in death, reflecting severity rather than exposure risk. Overall attack rate considers illness among all people in the group or population, not just those exposed to a single food item.