How should we prevent and control Norovirus during its peak season?

Recently, disease control departments in many places have issued reminders that norovirus has entered its peak period. Norovirus is a virus that causes non-bacterial acute gastroenteritis. It is highly contagious and often spreads in crowded places such as schools, kindergartens, hospitals, and nursing homes. So, what exactly is norovirus? How can we prevent and control it? Today, let's take a look at it in one article.

1. What is Norovirus?

Norovirus belongs to the genus Norovirus of the family Caliciviridae and is one of the common pathogens that cause acute gastroenteritis. Norovirus has strong resistance to physical and chemical factors, and is resistant to ether, ethanol, and acid. It can survive in the temperature range of 0℃ - 60℃, and can withstand 3 hours at room temperature of pH 2.7, 18 hours at 4℃ for 20% ether, and 3.75 - 6.25mg/L of chloride ion concentration in ordinary drinking water (free chlorine 0.5 - 1.0mg/L). It is difficult to inactivate the virus with commonly used disinfection methods such as alcohol and rinse-free hand sanitizer. Using chlorine-containing disinfectants for 30 minutes can inactivate the virus.

Norovirus infection can occur throughout the year, but in my country the peak period is from October to March of the following year.

2. Transmission channels

It is highly infectious and can cause infection at relatively low doses. It has various transmission routes, including:

(1) Transmission through close contact with an infected person; contact with the vomit, feces, etc. of an infected person; contact with the surface of an object contaminated by an infected person; ingestion of aerosols produced by the patient's feces or vomitus.

(2) Transmitted through food and water, eating food contaminated by norovirus; drinking water contaminated by norovirus.

The general population is susceptible to norovirus infection. After infection, they will have a certain resistance to the same type of virus, but infection with different types of viruses can still cause disease, so repeated infections may occur.

3. What are the symptoms after infection?

After the Norovirus invades the human body, it usually takes about 12 to 48 hours for the disease to develop, and can take up to 72 hours. The main symptoms are nausea, vomiting, diarrhea, and abdominal pain. The diarrhea is yellow watery stool or watery stool, which occurs several to more than ten times a day. Children mainly experience vomiting, while adults mostly experience diarrhea. Some patients may also have mild fever, headache, chills, muscle pain and other symptoms.

Norovirus infection is mostly self-limiting. When the disease develops to a certain stage, it can stop by itself and gradually recover. It can usually heal itself in 1-3 days. However, people with low immunity or weak body may show severe vomiting, diarrhea, dry mouth, thirst, decreased urine volume, electrolyte imbalance, etc. after infection. Those with extremely serious illness may die. About 30% of infected people may not show any symptoms, which are called latent infections, but they can excrete viruses in their feces, which is an important source of disease transmission.

4. How to prevent Norovirus infection?

Although norovirus infections can usually heal on their own, the illness can cause physical discomfort and may infect others. Therefore, it is crucial to take preventive measures during the peak period of norovirus infection.

1. Personal and Family Prevention

1. Keep your hands clean: Wash your hands correctly according to the 7-step hand washing method before meals, after defecation, and before processing food, and wash with soap and running water for at least 20 seconds. Alcohol-containing disinfectant wipes and hand sanitizers are ineffective against norovirus and cannot replace hand washing.

2. Pay attention to food and water hygiene: Do not drink raw water, drink boiled water or qualified bottled water. Wash vegetables and fruits thoroughly, cook food thoroughly, especially oysters and other seafood such as shellfish. When processing food, separate raw and cooked food, use different cutting boards, knives and containers to handle raw and cooked food to avoid cross contamination. When dining out, choose restaurants with good hygiene conditions and high reputation.

3. Home isolation of cases: Norovirus infected people should be isolated as much as possible from the time of illness to 3 days after recovery. During this period, patients should wash their hands frequently, keep their hands clean, try not to have close contact with other healthy family members, eat and sleep separately, and especially do not cook or take care of the elderly and infants. It is recommended that non-hospitalized patients be isolated at home for at least 72 hours after the symptoms disappear. People working in special positions, such as chefs and babysitters, should not return to work until fecal detoxification is completed.

4. Do a good job of environmental cleaning and disinfection: maintain a suitable indoor temperature and open windows for ventilation regularly. If you need to deal with the patient's vomit or excrement, use chlorine-containing preparations (such as 84 disinfectant) for disinfection. Alcohol and ordinary hand sanitizer are ineffective against norovirus. When cleaning items contaminated by vomit, you should wear plastic gloves and masks. You can use a towel soaked in chlorine-containing disinfectant to fully cover the wrapped dirt, and then slowly wipe it off to avoid direct contact with pollutants or aerosol transmission due to improper operation. The patient's home environment should also be disinfected according to the guidance of medical staff to avoid transmission within the family. Regularly disinfect high-frequency contact surfaces and key areas such as toilets; ensure the cleanliness of the kitchen and tableware, dispose of garbage in a timely manner, and keep it clean and tidy. Dining utensils can be disinfected by boiling for 30 minutes.

5. Maintain a healthy lifestyle: Maintain a healthy lifestyle such as regular work and rest, proper diet, and moderate exercise to enhance the body's resistance to viruses. Eat a balanced diet, get enough sleep, and exercise moderately to enhance the body's resistance and prevent infection.

2. Prevention in schools and childcare institutions

1. Timely discovery and standardized management of cases: Strictly implement morning (noon) inspections and registration of absences due to illness. Once patients with symptoms such as vomiting and diarrhea are found, they should seek medical treatment in a timely manner and be isolated and managed. If an abnormal increase in cases is found, report it immediately to the disease control agency and relevant administrative departments.

2. Strengthen the management of drinking water and food hygiene: provide safe drinking water, manage drinking water well, check for damage and leakage in the drinking water supply network, regularly clean and disinfect secondary water supply facilities, and conduct drinking water quality testing to ensure water supply safety. Supervise food raw materials and processing links, pay attention to separating raw and cooked food, and cook thoroughly.

3. Strengthen the health management of kitchen workers, childcare workers and other employees: Monitor the health status of kitchen workers and childcare workers. If they have symptoms related to intestinal infectious diseases such as diarrhea, vomiting, and nausea, they should stop working immediately and seek medical treatment in time to prevent them from going to work while sick. Wear masks and maintain good hand hygiene during food preparation and meal distribution.

4. Clean and disinfect the environment: Clean and ventilate public places on campus/park (such as classrooms, dormitories, canteens, libraries, toilets, etc.) regularly, and clean and disinfect key areas (such as door handles, stair railings, faucets, toilet buttons, elevator buttons, bed railings, etc.) regularly.

5. Scientific and standardized handling of vomitus: Vomitus and feces of cases should be handled by personnel who have received standardized training in accordance with relevant operating guidelines. The focus should be on disinfecting the surfaces of environmental objects, daily necessities, food processing tools, drinking water, etc. contaminated by vomitus and feces.

6. Carry out publicity and education: Make full use of WeChat public accounts, video accounts, WeChat groups, letters and other methods to carry out knowledge education on Norovirus prevention and control, and develop good hygiene habits such as washing hands frequently, eating cooked food and drinking boiled water.

5. What should I do if I am infected with Norovirus?

If you are unfortunately infected with norovirus, don't panic too much. There is currently no effective antiviral drug for norovirus infection. It is a self-limiting disease. Most patients have mild symptoms after onset and do not need treatment. They can recover after resting for 2-3 days. During this period, you can take sugar and saline or oral rehydration salts to replenish the water lost by vomiting and diarrhea.

In terms of diet, you should rest in bed and drink plenty of warm water after the onset of the disease. People with frequent vomiting and diarrhea should fast for 8-12 hours, and then gradually resume a normal healthy diet. During the recovery period, you should eat a light, low-fat diet and try to avoid eating too much spicy, greasy food, such as peppers, fatty meat, fried foods, etc., so as not to cause gastrointestinal discomfort. After recovery, it is also recommended to maintain a light diet with rich variety and balanced nutrition.

However, infants, young children, and the elderly, especially those with underlying diseases, should seek medical treatment in a timely manner if they frequently vomit or have diarrhea. You should also go to the hospital immediately if you experience the following symptoms:

(1) Symptoms of severe dehydration, such as dry mouth, thirst, significantly decreased urine volume, sunken eye sockets, and poor skin elasticity.

(2) Persistent high fever.

(3) Severe abdominal pain.

(IV) The occurrence of neurological symptoms such as confusion and mental depression.

In short, during the high incidence period of norovirus infection, we should understand the relevant knowledge of norovirus, take preventive measures, and protect the health of ourselves and others. If suspected infection symptoms occur, take the correct treatment method in time and seek medical treatment if necessary.