"If you don't let you eat ice cream, look, you're diarrhea!" Seeing the above sentence, does it seem like there is a sound in your ear? I believe you will definitely be familiar with this statement. When symptoms of vomiting and diarrhea occur, it may be the first to check the culprit in your diet to find out the inertial thinking of many people. Digestion may not be caused by food poisoning or cold catching, but may also be an infectious disease. The high-frequency cold drinks and cold food intake in hot summer, the survival temperature of some pathogens, and the more fragile gastrointestinal environment make digestive infectious diseases more likely to occur. The pathogens that cause infectious diseases are not necessarily transmitted through food. Ice cream, watermelon, flavored shrimp... may have really taken the blame.
Take the norovirus , which is easily infected in autumn and winter, as an example. The virus transmission routes include human-to-human transmission, food and water transmission. Human-to-person transmission can be transmitted through feces-oral routes (including aerosol produced by ingestion of feces or vomit) or indirect contact with an environment contaminated by excrement. Foodborne transmission is transmitted through the consumption of food contaminated by norovirus. The contamination process can occur when catering practitioners infected with norovirus contaminate food in preparing and serving meals. Food can also be contaminated by human excrement containing norovirus during production, transportation and distribution. Drinking water sources such as barreled water, municipal water supply, and well water may be contaminated by pollution [1].
Research data shows that in the transmission of norovirus, food and water transmission are not the most mainstream.
Routes of Norovirus infection. Image source: FieldsVirology, 6th, Ed, P597
can carry out human-to-person transmission, which is also an important reason why norovirus spreads rapidly and easily causes outbreaks in confined places (such as childcare institutions, kindergartens, schools, nursing homes, cruise ships, etc.).
Norovirus was discovered by scientists because of acute gastroenteritis that broke out in an elementary school in Novak Town, USA in 1968.
In 1972, scientists found a virus particle with a diameter of about 27nm in the feces of patients with this outbreak, and named it Novak virus , later also known as norovirus, Nowalk virus or pus fusion virus .
In 2002, the 8th International Virus Naming Committee changed the Novak virus, norovirus, nowalk virus, and pus fusion virus to Norovirus, becoming an independent genus of the Calicovirus family - Norovirus.
Image source: From the website of the International Virus Classification Committee Norovirus can cause acute gastroenteritis, manifested as diarrhea, vomiting, nausea or accompanied by fever, headache and other symptoms. Vomiting and nausea are common in children, and diarrhea is the most common in adults after they get sick. Because the incidence rate in winter is relatively high, it is also called winter vomiting disease.
The norovirus outbreak in my country was reported through the national public health emergency monitoring system. Among the 692 acute gastroenteritis outbreaks reported from January 2014 to December 2017, norovirus is an absolute dominant pathogen, accounting for about 89% (616/692). There are 616 norovirus outbreaks, involving about 30,000 cases, 93% (571/616) of the epidemic occurs in schools, and 63% (387/616) of the epidemic is transmitted through human-to-person contact [2].
Norovirus infectious diarrhea is a self-limiting disease with an average duration of 2-3 days and no sequelae after recovery. However, some patients may experience dehydration symptoms in continuous diarrhea, which may be life-threatening in severe cases.
There are currently no effective antiviral drugs, mainly for symptomatic or supportive treatment. Dehydration is the main threat of norovirus infectious diarrhea. For severe patients, especially young children and weak people, they should be infusion or oral rehydration in a timely manner to correct dehydration, acidosis and electrolyte disorders .
Norovirus is mainly excreted through the patient's feces, and can also be excreted through vomit. Norovirus is not only cold-resistant, but also heat-resistant, and can survive within the temperature range of 0-60℃. General disinfectants such as 20% ether and 3.75-6.25 mg/L chloride ion concentration in ordinary drinking water is ineffective. Ethanol and hand sanitizer cannot inactivate it.
Heat at 100°C and boil it or use a high concentration of chloride ions of 10 mg/L (chlorine ion concentration used to treat wastewater) to inactivate norovirus.
There is currently no vaccine to prevent norovirus. Its prevention and control mainly adopts non-pharmacological preventive measures:
1. Develop good hygiene habits: "Two must be two, two, no," it should be done. Wash your hands after returning home, before meals, and after toilets, and separate raw and cooked dishes and rice; do not drink raw water, and do not eat seafood, aquatic products and undercooked foods.
2. Disinfection: (1) Boiling and disinfection: Boiling and disinfecting tableware regularly, and all tableware must be covered with water, for 15-20 minutes; (2) Exposure to the sun and disinfection: Wash towels, bedding, etc. and expose the sun to the sun, and the exposure time should not be less than 6 hours.
3. Others: Pay attention to matters such as opening windows frequently for ventilation.
When caring for patients infected with norovirus, you also need to pay attention to disinfection and isolation. The specific precautions are as follows:
1. Since the patient will produce viral aerosol when vomiting, the room should be opened regularly for ventilation, generally ventilated twice a day for 30 minutes each time.
2. Wear gloves when caring for patients, especially when cleaning up vomit and excrement, and wear a mask. However, wearing gloves cannot replace washing hands, and you need to wash your hands before and after contacting the patient.
3. When dealing with items contaminated by the patient's vomit or excrement, you need to dip the disposable water-absorbing material (such as gauze, rag, etc.) into 5000-10000 mg/L chlorine-containing disinfectant (or high-concentration "84" disinfectant) completely cover the pollutants, carefully remove them, and avoid contact with pollutants during the removal process.
4. The contaminants in the toilet or container can be carefully (the purpose is to prevent liquid from splashing) and pour a sufficient amount of 5000-10000 mg/L of chlorine-containing disinfectant (or high-concentration "84" disinfectant) into the sewage treatment system.
5. The mop, rag and other tools used in cleaning, and the containers that contain contaminants must be soaked with a disinfectant solution containing 5000mg/L of effective chlorine (or high-concentration "84" disinfectant) for 30 minutes before rinsing thoroughly before using it again.
6. Mops in toilets and bathrooms should be used exclusively.
References:
【1】Liao Qiaohong, Ran Lu, Jin Miao, et al. Technical Guidelines for Investigation and Prevention and Control of Norovirus Infection Outbreak (2015 Edition). Chinese Journal of Preventive Medicine, 2016, 50 (1):7-16.
【2】Wang Yu, Gao Zhiyong, Jia Lei, et al. Epidemiological Research Progress in Norovirus Infection. Chinese Journal of Epidemiology, 2022, 43 (6):974-980.
Author｜Chen Dianjie Review of the Fifth Medical Center of the General Hospital of the People's Liberation Army｜Zhang Jieli Fifth Medical Center of the People's Liberation Army General Hospital, Deputy Chief Nursing Officer
(Popular Science China)
