This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Which is the most common etiologic agent of acute infantile gastroenteritis? 
Select and explain. 
A. Adenovirus, B. E coli, C. Norwalkvirus, D. Rota virus
D: Rota virus
Answer: D: Rota virus 
Explanation: Though none of the text books specifically mention most common causes of acute infantile gastroenteritis, most of the literature search in pubmed, cochrane and medscape and major text books of pediatrics point to: Viruses are more common causes of gastroenteritits in children. Of the viruses most common is rotavirus. Other viruses implicated are calciviruses, Norwalk, adenovirus. Also E.coli is a major cause of diarrhea in children. Other bacteria are: Campylobacterium, Yersinia enterocolitica, A. hydrophillia.