Which best describes why clinical areas are so careful to ensure sanitization of surfaces and equipment between each patient?

Correct Answer: C

Rationale: Indirect transmission is the spread of infection through a vehicle of transmission outside the host. These may be contaminated fomites or vectors. Fomites can be any inanimate object, material, or substance that acts as a transport agent for a microbe (e.g., water, a telephone, or a contaminated tissue).

Correct Answer: C

Rationale: Attributable risk is determined by subtracting the rate of disease among nonexposed individuals (such as athletes) from the rate of disease among those exposed (the individuals with a sedentary lifestyle).

Correct Answer: B

Rationale: Nutritional deficiencies are included under agent factors. Although too much of an agent can cause disease (such as obesity related to diabetes), so can too little of an agent. Relative risk indicates the extent of excess risk incurred by exposure relative to nonexposure. Host factors are intrinsic factors and describe one's susceptibility or response influence to the exposure to the agent, such as genetics, age, sex, ethnicity, and human behavior. Environment factors are extrinsic factors and they influence the existence of the agent, exposure, or susceptibility to the agent such as physical environment, biological environment, and socioeconomic environment.

Correct Answer: D

Rationale: Causation assessment (e.g., Bradford Hill criteria) includes strength of association (A), temporality (B), and reversibility (C), among others. All are considered (D) to evaluate if an exposure causes an outcome (e.g., smoking cessation reducing lung cancer risk supports causality).

Correct Answer: A

Rationale: Incubation period (A) is from exposure to symptom onset (e.g., measles: 10–14 days). B, C, and D describe other intervals.