Which of the following is a common symptom of an infection?

Malaise is a common symptom of an infection because it refers to a general feeling of discomfort or unease, often accompanying infectious diseases. When the body is fighting off an infection, it can trigger a range of responses, including fatigue, weakness, and a lack of energy, all of which are encompassed in the feeling of malaise. This symptom is often one of the first indicators that the body is dealing with an underlying health issue, particularly infections.

In contrast, hypertension, while it can occur in response to stress or certain medical conditions, is not specifically linked to infections. Diarrhea can occur with some types of infections, particularly gastrointestinal infections, but it is not universally present with all infections. Insomnia may result from overall discomfort or illness, yet it is not a direct symptom of an infection itself. Thus, malaise stands out as the most representative symptom indicative of an infection.