viruses in human intestine

virus gut intestine 3d rotavirus system gastrointestinal health flora stomach flu colon covid measles digestive human cmv infection children leaky parainfluenza medicine intestinal cell disease large diarrhoea digestion microvilli tract unhealthy bad anatomy illustration probiotics hepatitis a e viral enteric diarrhea norwalk norovirus vomiting nausea adenoviruses astrovirus cytomegalovirus adenovirus villi