Pediatrics The most common etiological agent for acute bronchiolotis in infancy is: March 2011 A Influenza virus B Parainfluenza virus C Rhino virus D Respiratory Synctial virus 💡 Explanation The most common etiological agent for acute bronchiolotis in infancy is: March 2011 ✓ Correct Answer: D. Respiratory Synctial virus