Which of the following is not a sign of infection?

Improved appetite serves as an indicator of health and well-being rather than a sign of infection. Infections typically lead to a systemic response in the body, which can manifest through various signs such as redness, swelling, and fever. Redness and swelling are local signs that indicate increased blood flow and an inflammatory response at the site of infection, while fever is a systemic response that often accompanies infections as the body raises its temperature to fight off pathogens. In contrast, an improved appetite suggests that the body is functioning well and not in a state of distress, which is contrary to what is expected during an infection. Thus, identifying improved appetite as not being a sign of infection is accurate within this context.