Surveillance can best be described as:

Correct Answer: A

Rationale: Surveillance in public health is a systematic, ongoing process of collecting, analyzing, and interpreting data to monitor health events, such as infections, particularly in settings like healthcare facilities. While it can involve tracking infections (A), it is broader than just recording patient attendance (B) or sterile pack storage (C), and it is purposeful, not random (D).

Correct Answer: D

Rationale: Point prevalence surveillance provides a snapshot of disease burden at a specific time, unlike continuous surveillance (A). It can be repeated periodically (B), and typically requires fewer resources than continuous surveillance (C), making it a practical tool for periodic assessment.

Correct Answer: C

Rationale: HAI rates are generally higher in low-income countries due to limited resources, weaker infrastructure, and less robust IPC programs compared to high-income countries, where surveillance and prevention are more advanced.

Correct Answer: B

Rationale: An epidemic refers to disease levels exceeding normal expectations and being more prolonged or widespread than localized outbreaks, distinct from endemic levels (A), pandemics (C), or the study of epidemiology (D).

Correct Answer: D

Rationale: The first step in outbreak investigation is to agree on a case definition to consistently identify cases, which guides subsequent steps like sample collection (B), meetings (C), and data organization (A).