<prompt> Viral enterotoxin is detected as a possible mechanism of pathogenesis in :Adeno virusRota virusCalcivirusAstrovirus  <response>: Mechanism of Rotavirus diarrhea :a. Rotavirus destroy mature enterocytes of proximal small intestine.Loss of absorptive villi and proliferation of secretory crypt cells Secretory diarrheaBrush border enzymes are reduced so unmetabolized disaccharides accumulates resulting. Osmotic diarrheab. NSP4 enterotoxin which alteres epithelial cell function and permeability causing secretory diarrhea.c. Virus evoke fluid secretion by the activation of enteric nervous system in intestinal wall. 