Which of the following could be a symptom of a communicable disease?

A persistent cough is indeed a common symptom associated with various communicable diseases, particularly those affecting the respiratory system. For instance, conditions such as influenza, tuberculosis, or even COVID-19 often present with a chronic cough as the body tries to clear respiratory pathogens. This symptom is significant as it may indicate the presence of an infection that could spread from one person to another.

In the context of communicable diseases, symptoms like a slight headache can occur for various reasons unrelated to infectious agents. Fatigue after exercise is generally a normal response to physical activity and not indicative of a disease process. A normal respiratory rate suggests that an individual is not currently experiencing distress or infection, which would typically alter that rate if a disease were present. Thus, persistent coughing is a clear symptom that can signal a communicable disease and necessitates attention for both personal health and the health of those around the individual.