The public health nurse understands that immediate treatment for a possible sexually transmitted infection is secondary prevention. Once there is a confirmed diagnosis, the public health nurse knows that this is now which of the following levels of prevention?

Choice A reason: Appendicitis causes abdominal pain, not farmworker symptoms broadly. Pesticide fits, per nursing standards. This errors in symptom match. It’s universally distinct.

Choice B reason: Gastroenteritis lacks dizziness, concentration issues; pesticide covers all. This misaligns with occupational health. It’s universally distinct, incomplete symptom fit.

Choice C reason: Viral illness is vague; pesticide explains farmworker exposure symptoms. This errors per nursing specificity. It’s universally distinct, less likely here.

Choice D reason: Pesticide poisoning causes dizziness, thirst, vomiting, fatigue, headache in farmworkers. This aligns with occupational health standards. It’s universally distinct, accurate.

Choice A reason: Acquired immunity includes any immunity gained post-birth, like via vaccines or infection. It’s broad, encompassing this scenario, but less specific than active immunity, which details the body’s direct response to measles antigens, producing antibodies and memory cells for long-term protection explicitly.

Choice B reason: Active immunity occurs when vaccinations trigger the immune system to produce antibodies against measles virus antigens. This process, involving B and T cells, builds memory, offering lasting protection, distinguishing it from passive or natural methods by its active, self-generated response biologically and effectively.

Choice C reason: Herd immunity arises when most of a population is immune, reducing measles spread indirectly. Vaccination contributes, but this describes a community effect, not the individual immunity type gained directly from the shot, which is the question’s specific focus here distinctly.

Choice D reason: Natural immunity follows actual measles infection, not vaccination. It involves the body fighting the live virus, unlike the controlled antigen exposure from shots, which mimics this process artificially, making it less applicable to the immunity type described in this scenario fully.