A town of 20,000 has 80 reported cases of influenza in one week. Calculate the weekly incidence per 1,000 population and assess whether a threshold of 4 cases per 1,000 per week has been exceeded. Show your work.

• A. 4 per 1,000 per week; the threshold of 4 per 1,000 has been met and warrants heightened surveillance and consideration of control measures.
• B. 0.4 per 1,000 per week; the threshold has not been met and no action is needed.
• C. Incidence cannot be calculated without knowing the age distribution of the cases, so no interpretation is possible from the provided data.
• D. 40 per 1,000 per week; the threshold has been dramatically exceeded and immediate lockdown is the only option.

Answer: (A)