Which scenario would prompt a call to Public Health Authorities?

When a communicable disease is suspected, it is crucial to alert Public Health Authorities. This is because communicable diseases can spread quickly and pose significant health risks to the public, especially in crowded environments like an airplane. Notifying health authorities allows for prompt investigation and necessary actions to contain and mitigate the spread of the disease, ensuring the safety of both passengers and crew.

In contrast, while minor injuries, allergic reactions, and passenger complaints may require attention and appropriate response, they generally do not present the same level of urgency or risk associated with communicable diseases. These situations often can be managed internally by the onboard staff without the immediate need for external intervention from health authorities.