Which is the first step in preventing further spread of a particular sexually transmitted disease (STD)?

Correct Answer: D

Rationale: Antiinfective drugs, such as antibiotics, antivirals, antiretrovirals, and antimalarials, play important roles in controlling infectious diseases. Not only do they permit recovery of the infected person, but they also play a major role in preventing transmission of the pathogens to another. The first step in preventing transmission of tuberculosis and syphilis is to treat the infected person with antibiotics. Because the question asks about further spread, infection in a person has been diagnosed, so education is needed, but it is too late for that person. Adults not in school also are infected with STDs. A stronger, more effective sanitizing agent would not be the most effective strategy to prevent spread of STDs.

Correct Answer: D

Rationale: A risk factor of less than one means the factor is actually protective, so the inexpensive lotion is helpful in preventing skin sores. A risk factor of more than one means the factor increases risk, so using the expensive lotion increases the probability of getting a skin lesion.

Correct Answer: D

Rationale: As treatment was knowingly withheld over many years resulting in incredible harm to the subjects and their families, public outrage over unethical, racist, and discriminatory behavior of the researchers continues today.

Correct Answer: A

Rationale: Randomization in RCTs (A) balances confounders (e.g., age, sex) across groups, reducing bias and isolating the intervention’s effect. B is false; precision depends on tools, not design alone. C is incorrect; RCTs measure exposure first, outcome later. D is irrelevant; motivation doesn’t ensure causality.

Correct Answer: B

Rationale: Epidemiology studies disease distribution and determinants (B) to inform public health. Vaccine development (A), treatment (C), and training (D) are not its primary aims.