In October 2016, dozens of students at a university were infected with norovirus and experienced digestive discomfort with vomiting, fever, and diarrhea. A total of 39 students at the university were infected with norovirus, and after timely isolation, eight more students who were looking after isolated patients were reinfected. After investigation, the cause of discomfort for the norovirus caused by infectious diarrhea. Norovirus for what demon? Norovirus (Norovirus) its prototype strain of Norwalk virus (Norwalk-like viruses) was isolated and found in the United States in 1968 in the city of Norwalk, because the group of viruses is very easy to mutate, since then in other areas and named a variety of similar viruses, collectively known as Norovirus. Norovirus and Sapporo-like Virus (SLV) found in Japan, now officially known as Sapovirus (SV), are collectively known as the human cup virus. Norovirus characteristics: diameter of about 26-35nm, no envelope, rough surface, spherical, icosahedral symmetry; isolated from the stool of patients with acute gastroenteritis, can not be cultured in cells or tissues, and there is no suitable animal model; genome is a single-stranded positive-stranded RNA . Norovirus is highly genetically variable, and there may be epidemics of strains with different genetic characteristics during the same period and within the same community. Norovirus antibodies have no significant protective effect, especially no long-term immune protection, and are highly susceptible to recurrent infections. Norovirus is highly infectious, mainly intestinal transmission, with rapid onset, fast transmission, and wide involvement, and is the main cause of non-bacterial diarrhea outbreaks. It can be spread through contaminated water, food, articles, air, etc., and often causes collective outbreaks in communities, schools, restaurants, hospitals, nurseries, orphanages and the military. The incubation period is 24 to 48 h, with a minimum of 12 h and a maximum of 72 h. The onset of infection is sudden, with the main symptoms being nausea, vomiting, fever, abdominal pain and diarrhea. Vomiting is common in children and diarrhea is common in adults, with diarrhea occurring 4-8 times in 24h. The stool is dilute watery stool or watery stool without mucus and pus. Patients with primary infection have significantly more vomiting symptoms than those with secondary infection, and some infected patients show only vomiting symptoms. In addition, symptoms such as headache, chills and muscle pain can be seen, and in severe cases, dehydration can occur. The course of the disease is self-limiting, usually recovering in 2 to 3 days. Diagnosis: Based on epidemiological data such as epidemic season, region, age of onset, clinical manifestations and detection of norovirus in stool specimens or vomit, the case can be diagnosed. Treatment: No special antiviral drugs, symptomatic or supportive treatment, generally without the use of antibacterial agents, healing well. Dehydration is the main cause of norovirus infectious diarrhea, for serious cases, especially young children and frail people should be timely infusion or oral rehydration to correct dehydration, acidosis and electrolyte disorders. Preventive measures As norovirus infection is a common intestinal infectious disease, it is easy to occur in crowded places with local aggregation of cases. Therefore, we should work together for prevention. 1, pay attention to personal hygiene, wash hands regularly; 2, do not eat raw and cold food and undercooked food, and reduce the number of off-campus restaurants, especially unlicensed street stores; 3, reduce the opportunity to go out to meetings and participate in large activities when the epidemic is prevalent, to eliminate the channels of infection; 4, as soon as there is a situation, immediately seek medical advice and report the unit, the community. Isolation: The patient, suspected patient and carrier should be isolated and treated separately. Disinfection: Disinfect the vomit and diarrhea of patients, suspected patients and carriers and contaminated objects, air, drinking water and toilets at any time, and carry out final disinfection when the infected person is sent to an isolation ward or after cure. Immunization: No ideal vaccine is available.