Spring diarrhea, beware of Norovirus "tricks"

This is the 3158th article of Da Yi Xiao Hu

Norovirus is the main pathogen of sporadic cases and outbreaks of acute gastroenteritis worldwide. Since 2013, outbreaks of other infectious diarrheal diseases in my country have been mainly caused by norovirus, especially since 2014, when the number of norovirus outbreaks has increased significantly, significantly higher than in previous years.

What is Norovirus?

Norovirus, also known as Norwalk virus, is a virus of the genus Norovirus in the family Caliciviridae. It is a group of virus particles with similar morphology and slightly different antigenicity.

Norovirus-induced diarrhea is prevalent worldwide and can occur throughout the year. It mainly affects adults and school-age children, with a higher incidence in cold seasons. In the United States, 60%-90% of all non-bacterial diarrhea outbreaks are caused by norovirus each year. Similar results have been found in developed countries such as the Netherlands, the United Kingdom, Japan, and Australia. In China, the detection rate of norovirus in children under the age of 5 with diarrhea is about 15%, and a survey of serum antibody levels shows that norovirus infection is also very common in the Chinese population.

What are the symptoms of norovirus?

The main symptoms are nausea, vomiting, fever, abdominal pain and diarrhea. Vomiting is common in children, and diarrhea is more common in adults, with 4 to 8 episodes of diarrhea within 24 hours. The stool is watery or watery, without mucus, pus or blood. Patients with primary infection have significantly more vomiting symptoms than those with secondary infection, and some infected patients only show vomiting symptoms. In addition, symptoms such as headache, chills and muscle pain can also be seen, and dehydration symptoms may occur in severe cases. Patients with a long course of illness and severe conditions also have a longer detoxification time, and the infectiousness can last until two days after the symptoms disappear. The immune period of this disease is short and repeated infections can occur.

Is Norovirus contagious?

my country has always included it in the Class C infectious diseases "other infectious diarrheal diseases (infectious diarrheal diseases other than cholera, bacillary and amoebic dysentery, typhoid and paratyphoid)" for reporting management.

Sources of infection: Patients, latently infected persons and virus carriers are the main sources of infection.

Transmission routes: Norovirus can be transmitted from person to person, through food, and through water. Human-to-human transmission can be through the fecal-oral route (including ingestion of aerosols produced by feces or vomitus), or indirect contact with an environment contaminated by excrement. Foodborne transmission is through eating food contaminated by norovirus. The contamination link can occur when catering workers infected with norovirus contaminate food during meal preparation and service, or when food is contaminated by human excrement or other substances (such as water) containing norovirus during production, transportation, and distribution.

Susceptible population: People are generally susceptible to norovirus.

Norovirus Prevention

1. Cut off the transmission route

The main transmission route of viral diarrhea is "fecal-oral" transmission, and the sources of infection are mostly mild patients or asymptomatic carriers. Therefore, the main preventive measures are to do a good job in food and drinking water, strengthen the management of patients, close contacts and their direct contact environment, and actively cut off the transmission routes of the disease.

2. Control the source of infection

Patients who have already developed the disease should be isolated and treated, and should rest at home until the symptoms disappear for 3 days to avoid spreading the disease to people around them. Disinfect the vomit and diarrhea of ​​patients and suspected patients, as well as contaminated items and toilets. Mild patients can be isolated at home or in the institution where the epidemic occurs; those with severe symptoms need to be sent to medical institutions for isolation and treatment according to intestinal infectious diseases. Medical institutions should do a good job of infection control to prevent hospital transmission.

3. Avoid diseases from the mouth

Do not eat raw or cold food or uncooked food, especially raw shellfish and other aquatic products; it is best to eat less or no cold dishes that have been left for a long time. Boil drinking water before drinking, and do not drink raw water.

4. Cook food thoroughly

Avoid eating undercooked food. Norovirus will die if it is exposed to high temperatures above 80°C for 30 seconds. Therefore, you can prevent it by cooking food thoroughly, especially seafood and shellfish.

In our daily lives, we carry out publicity of knowledge on the prevention and control of Norovirus infection, raise the awareness of prevention and control among community residents, and cultivate healthy living habits such as washing hands frequently, not drinking raw water, keeping raw and cooked food separate, and avoiding cross contamination.

Author: Emergency Department, The Second Affiliated Hospital of Xi'an Jiaotong University

Chief Physician Pei Honghong

Emergency Department, The Second Affiliated Hospital of Xi'an Jiaotong University

Written by Zhang Qiong, head nurse