What type of study is the public health nurse using to collect exposure and lifestyle information to assess the relationship between these factors and consequent occurrence of disease?

Correct Answer: C

Rationale: The correct answer is C: Cohort study. In a cohort study, the public health nurse follows a group of individuals over time to assess the relationship between exposure and disease occurrence. This type of study allows for the determination of potential cause and effect relationships. In contrast, an experimental study (choice A) involves intervention and manipulation of variables. A cross-sectional study (choice B) captures data at a single point in time without following individuals over time. A case-control study (choice D) involves comparing individuals with and without a disease to identify factors associated with the disease but does not provide information on the temporal sequence of exposure and disease occurrence.

Correct Answer: A

Rationale: The correct answer is A: Measles. Measles is spread through airborne transmission via respiratory droplets. The virus is highly contagious and can remain in the air for up to two hours after an infected person has left the area. Measles outbreaks often occur in crowded places like schools. Influenza (B) is also spread through respiratory droplets, but measles is more commonly known for airborne transmission. Pertussis (C) is spread through respiratory droplets but is not primarily airborne. Pneumonia (D) is not a communicable disease spread through the air.

Correct Answer: C

Rationale: The correct answer is C: Dehydration. Mild to moderate food poisoning commonly leads to dehydration due to fluid loss from vomiting and diarrhea. Dehydration is a key concern as it can lead to serious complications. Incorrect choices: A: Bloody diarrhea is more indicative of severe food poisoning or infections like E. coli. B: Diarrhea lasting more than 3 days suggests a more severe case or underlying condition. D: Fever less than 102°F is not specific to food poisoning and can occur in various illnesses.

Correct Answer: A

Rationale: Recent scientific discoveries on the infectious etiology of stomach ulcers, coronary artery disease, and cervical cancer, for example, suggest that infectious agents may be responsible for more morbidity and mortality than previously recognized. Mortality caused by infectious diseases has decreased. Endemic refers to a disease that is regularly found among people in a certain area. In our society today, there are no endemic infectious diseases. Advances in public health and health care have made it easier to control infectious diseases such as H1N1 flu.

Correct Answer: C

Rationale: Herd immunity is a state in which those not immune to an infectious agent will be protected if a certain proportion (generally considered to be $80 \%$ ) of the population has been vaccinated or is otherwise immune. If most persons are immune, it will be difficult for an infectious disease to spread.