A nurse is caring for a child who has rheumatic fever. When obtaining the child's medical history from the parent, the nurse should recognize the significance of which of the following data as the possible source of the child's infection?

A. Gastritis in the father is unrelated to rheumatic fever, which is linked to streptococcal infections, not gastrointestinal issues. B. Chickenpox, caused by the varicella-zoster virus, is not related to rheumatic fever. C. A sibling who had a sore throat 3 weeks ago is significant because rheumatic fever often follows an untreated or inadequately treated streptococcal throat infection. Recognizing a recent history of streptococcal infection is key to understanding the source of the child's rheumatic fever. D. Fifth disease, caused by parvovirus B19, is also unrelated to rheumatic fever.