Final answer:
The most common causative agent for infantile diarrhea is rotavirus, which is responsible for 70% of childhood gastroenteritis worldwide. E. coli is also a common causative agent for diarrhea in infants.
Step-by-step explanation:
The most common causative agent for infantile diarrhea is rotavirus. Rotaviruses are a type of virus that can cause gastrointestinal illnesses and are responsible for 70% of childhood gastroenteritis worldwide. Other common causative agents for diarrhea in infants include E. coli.