Which symptom is least likely to be associated with rotavirus infection?

Rotavirus is primarily associated with gastrointestinal symptoms, particularly in infants and young children. It is a leading cause of severe diarrhea, often accompanied by vomiting, and can also present with fever. The primary mechanism of rotavirus infection is the replication of the virus in the intestinal epithelium, leading to significant fluid loss and subsequently, diarrhea.

The presence of rusty sputum, however, is not a typical symptom associated with rotavirus infections. Rusty sputum is more often linked to bacterial pneumonia, particularly infections with Streptococcus pneumoniae, where blood and rust-colored fluid in cough material indicate a lung involvement rather than a gastrointestinal one. Hence, rusty sputum doesn't align with the usual clinical presentation of rotavirus. Therefore, identifying this symptom as least likely linked to rotavirus infection is justified.