About infectious gastroenteritis (norovirus, etc.)

Infectious gastroenteritis due to norovirus is an infectious disease that is prevalent mainly in winter, but is seen throughout the year.
Let's understand the characteristics of norovirus and prevent infection.

• About infectious gastroenteritis (especially norovirus) (outside site)(Ministry of Health, Labour and Welfare)
• Wash "hand" with soap (PDF: 320KB)(Yokohama City Public Health Center)
• Norovirus, influenza epidemic! （PDF：475KB）(Yokohama City Public Health Center)

Infectious gastroenteritis is a general term for infectious diseases that cause gastroenteritis symptoms such as diarrhea and vomiting caused by bacteria and viruses, and many of the causative pathogens are norovirus.
In addition, there are rotavirus, sapovirus, adenovirus, astrovirus, etc.

In Yokohama City, we receive reports of infectious gastroenteritis every week from fixed-point medical institutions in the city.
In addition, outbreaks occur every year in infant facilities (nursery schools, kindergartens, etc.), schools, facilities for the elderly, hospitals, etc.
In places where people live in a group life, it is necessary to be careful not to be infected on a daily basis, and to take measures to prevent the spread of infection promptly if an infected person is confirmed in the facility.

• Trends in the number of patients by disease per reported fixed point in graph (infectious gastroenteritis)(Yokohama City Inst. of Health)
• Easy-to-understand information on infectious diseases in Yokohama! Click here for the Medical Dashboard (external site)

• Norovirus is a virus that causes acute gastroenteritis in people of all ages and is so infectious that it can be transmitted even if the virus is extremely small that it is less than 100.
• It occurs throughout the year, but is especially prevalent in winter (November to February).
• When infected with norovirus, symptoms such as diarrhea, vomiting, and fever appear after an incubation period of approximately 1 to 2 days.
• It usually recovers in one or two days after onset, but caution is required for infants and the elderly with weak resistance, as they may become more severe or clogged vomit in the trachea.
• Q & A about norovirus (outside site)(Ministry of Health, Labour and Welfare)

Norovirus infects humans by entering through the mouth.

1. Infectious disease route
   When norovirus adheres to the fingers when treating the vomit of an infected person, etc., and enters the body through the fingers and becomes infected.
   Or when infected by inhaling a dry and floating norovirus.
   ※The route where secondary infection occurs most frequently.
2. Food poisoning route
   When an infected person attaches norovirus to the food while cooking, and another person who ate the food is infected.
3. Food poisoning route
   Infected by eating bivalves, etc. that have accumulated norovirus, raw or without sufficient heating.

• The most effective infection prevention is hand washing. Wash your hands thoroughly before cooking or after the toilet.
• Get enough sleep and nutrition on a regular basis and keep your physical condition healthy.
• The infectivity of norovirus is lost by heating at 85 ° C for 1 minute or more. Especially for food, heat at a central temperature of 85 to 90 ° C for at least 90 seconds.
• If you are infected with norovirus, you may continue to excrete the virus for one week after recovery, and for a long time for about one month. Therefore, infection prevention measures such as hand washing are very important.

• Wash your hands thoroughly with soap and running water before cooking or eating, after toilets and waste disposal.
• Cut your nails short to prevent the virus from entering the gaps in your nails.
• Before washing your hands, remove your rings and watches so that there is no remaining Shiga.
• Foam the soap thoroughly and wash your fingers. Let's wash between your nails.
• After foaming with running water, wipe your fingers thoroughly with a clean towel or paper towel. Also, avoid sharing towels as much as possible.
• Hand washing method (PDF: 402KB)(prepared by Yokohama City Public Health Center and Ward Health and Welfare Center)

The vomiting and feces of infected people contain a large amount of norovirus, and the norovirus drifts in the air when dried, which can cause secondary infection when entering the mouth.
Therefore, treat vomit immediately, and provide sufficient ventilation during and after treatment.

• Do not touch vomit with bare hands, but use disposable gloves.
• Use a disposable mask when processing, and be careful not to pollute your clothes with vomit.
• Put vomit (including paper used for wiping) in a plastic bag, seal your mouth tightly, and dispose of it immediately. Before sealing the plastic bag, put a disinfectant to disinfect the vomit.
• When all the treatments are completed, be sure to wash your hands thoroughly.

• To disinfect norovirus, be sure to use a chlorine-based disinfectant (sodium hypochlorite in the component). Alcohol may not have an effective disinfection effect.
• To disinfect toilet doorknobs and cooking utensils, use a disinfectant with a chlorine concentration of 0.02% (200 ppm) to wipe it out soak.
• Disinfection of the floor, etc., which is dirty with vomit, etc., and use a higher concentration of 0.1% (1000 ppm) disinfectant to soak it.
• If chlorine-based disinfectants cannot be used, such as discolored clothing, wash them thoroughly and then disinfect them with steam (at least 85 ° C for at least 1 minute) such as boiling water or steam iron. In addition, norovirus remains in the washroom that was washed down, so let's disinfect it properly.

• Treatment and disinfection method of vomit (PDF: 504KB)Please refer to it.

• In order to maintain the disinfecting effect, store the undiluted solution in a place where it can be shaded.
• Diluted disinfectants lose their disinfecting effect over time. Don't make it, but make it every time it is disinfected.
• It can corrode metal materials. After disinfection, wash with tap water immediately or wipe it off.
• When used for clothes, carpets, etc., the color may fade.
• When using, be sure to provide sufficient ventilation. If mixed with acidic detergents, chlorine gas may be generated and it is dangerous, so do not use it together.
• It cannot be used for disinfection of fingers, etc., because it causes skin roughness.

If a person who has already been infected with norovirus cooks a meal, norovirus may adhere to the food, and the person who ate it may cause secondary infection.

• Care should be taken on a daily basis, and if you have symptoms such as diarrhea or vomiting, refrain from directly handling food.
• Foods that may be contaminated with the virus or foods that require sufficient heating should be heated at a central temperature of 85 to 90 ° C for at least 90 seconds.
• For cutting boards, kitchen knives, tableware, towels, etc., it is effective to heat and disinfect for 1 minute with boiling water (85 ° C or more).

Norovirus does not have effective antiviral agents or vaccines.
Therefore, the following coping therapy will be performed.

• While diarrhea or vomiting continues, dehydration and tends to lose physical strength. Make sure you have enough water and nutrition.
• In particular, infants and the elderly with weak resistance should hydrate frequently.
• If the symptoms are severe or prolonged, consult a medical institution as soon as possible.

If you or your family have symptoms, be very careful as there is a risk of secondary infection.

• Let's carry out disposal and disinfection of vomit immediately by appropriate procedure.
• Wash your hands frequently with soap.
• Disinfect areas that are touched with bare hands, such as toilet doorknobs.
• Change the water in the bath every day, and keep the bathtub and washroom floors, washbasins, chairs, etc. clean.
• If you have diarrhea, take a bath at the end.
• Don't share towels or bath towels.

When a person who cooks or assists with meals is infected, norovirus may adhere to the food, and those who eat it may also have food poisoning symptoms.

• People involved in meals, such as cooks and those who assist with meals at facilities, should manage their health on a daily basis.
• If you have poor physical condition such as diarrhea, please refrain from engaging as much as possible.

• Health and Welfare Center Health and Welfare Division Health Promotion Section
• Health and Welfare Center Health Sanitation Division (in charge of food hygiene and medical and pharmaceutical affairs)
• City of Yokohama, Medical Care Bureau Health and Safety Division (TEL045-671-2463, FAX045-664-7296)
• City of Yokohama, Medical Care Bureau Food Sanitation Division (TEL045-671-2460, FAX045-641-6074)

• Weekdays from 8:45 to 17:00 ...Health and Welfare Center Health and Welfare Division Health Promotion Section
• Outside of the above hours ...Emergency call dial for infectious diseases and food poisoning