FIG 7.

Proposed model for how human enteric adenovirus (HAdV) causes secretory diarrhea. Adenovirus infects enterocytes in the small intestine. Released virus, the knob domain of the short fiber, and hexon protein stimulate enterochromaffin (EC) cells to release serotonin (5-HT). Released 5-HT activates enteric nerves and enteric glia cells (EGC), the latter located near EC cells, and is associated with regulation of gut barrier and intestinal motility functions. Nerves within the submucosal plexus activate crypt cells to stimulate NaCl and water secretion, resulting in diarrhea. Stimulation of the myenteric plexus results in increased motility. The proposed model is based on a human rotavirus disease model (5, 22, 23, 72).