Which description of disease activity in a single area corresponds to endemic levels of disease?

Correct Answer: A

Rationale: Rationale for Correct Answer A: - Endemic levels refer to consistent, expected rates of disease in a specific area. - Choice A states there are usually 20-30 cases each week, consistent with endemic levels. - The fact that there were 29 cases this past week aligns with the usual range, indicating endemicity. - This means the disease is consistently present in that area without significant spikes or drops. Summary of Incorrect Choices: - Choice B: The usual rate in this choice is much lower than endemic levels, making it unlikely to be endemic. - Choice C: The usual rate is exceeded significantly in the past week, indicating an outbreak rather than endemicity. - Choice D: The global scale mentioned is not relevant to determining endemic levels in a single area.

Correct Answer: A

Rationale: The correct answer is A: Pathogenicity. In the epidemiological triad model, pathogenicity refers to the ability of an agent to cause disease. This factor is crucial as it directly relates to the agent's capability to infect and harm individuals. Pathogenicity influences the agent's virulence, infectivity, and capability to cause disease outbreaks. Susceptibility (B) refers to the host's vulnerability to the agent and is not directly related to the agent itself. Reservoirs (C) refer to the environment where the agent resides and can multiply, but it is not a factor related to the agent's inherent characteristics. Environmental changes (D) may affect the transmission of the agent but do not specifically relate to the agent's properties. Therefore, pathogenicity is the most relevant factor related to the agent when discussing the epidemiological triad.

Correct Answer: D

Rationale: The correct answer is D because sharing needles or other equipment contaminated with blood is a significant risk factor for contracting hepatitis C. By instructing individuals to avoid sharing such equipment, the nurse is targeting a key mode of transmission for the virus. This primary prevention strategy directly addresses the root cause of hepatitis C transmission in high-risk populations. Choice A is incorrect because while screening for hepatitis C is important, it is not a primary prevention strategy. Choice B is incorrect as handwashing is essential for preventing the spread of infections like hepatitis A and E, not hepatitis C. Choice C is incorrect because immunizations against other viral hepatitis infections do not protect against hepatitis C specifically. In summary, advising individuals to avoid sharing needles or equipment contaminated with blood is the most effective primary prevention strategy for hepatitis C compared to the other choices provided.

Correct Answer: B

Rationale: The correct answer is B: Engaging in contact tracing. Secondary prevention aims to identify and intervene early in the course of a disease to prevent its progression. Contact tracing helps to identify individuals who may have been exposed to the infectious disease, allowing for early intervention to prevent further spread. Administering immunizations (A) is a form of primary prevention to prevent the initial occurrence of the disease. Providing direct care to infected individuals (C) is a form of tertiary prevention aimed at managing the impact of the disease. Educating the public about disease transmission (D) is essential for prevention but does not directly involve early identification and intervention like contact tracing.

Correct Answer: D

Rationale: Probably one of the most profound failures in infectious disease control in the United States and elsewhere is that the successes are not equally distributed in the general population. Infectious diseases continue to be differentially distributed by income and ethnic groups, and the poor and minorities continue to experience the greater burden. There continues to be an increase in vector-borne infections, but there has been a decrease in food-borne and waterborne infections. There is concern that deadly pathogens will be weaponized by terrorists.