Which of the following is a symptom of a systemic infection?

A systemic infection occurs when pathogens enter the bloodstream and affect the entire body, leading to widespread symptoms. Fever and chills are classic indicators of a systemic infection. The body's immune response to the infection often results in an elevated body temperature (fever) as a mechanism to combat the invading pathogens. Chills can occur as the body tries to reach this higher temperature or can result from the body’s response to the infection itself.

In contrast, symptoms like pain at the infection site, redness and swelling, and drainage from a wound are more localized signs and symptoms typically associated with localized infections, where the inflammatory response is confined to a specific area. These localized responses may not indicate that the infection has spread throughout the body, as is the case with a systemic infection characterized by systemic symptoms such as fever and chills. Therefore, fever and chills directly signify a systemic response to infection, making them the distinguishing symptoms in this context.