Norovirus Photo: CFP

China's Guangdong, Jiangsu and Henan provinces have recently issued public warnings that the norovirus which can cause acute infectious diarrhea has entered its peak season, calling on schools to be extra vigilant against the virus.

Recently, elementary and secondary schools in South China's Guangdong Province began their spring semester, exposing students to a variety of infectious diseases, according to the Guangdong Provincial Center for Disease Control and Prevention (Guangdong CDC).

The Guangdong CDC noted that in the past two years the norovirus outbreak in the province in autumn and winter shows a high incidence, and the outbreak peak of norovirus infection is usually from September to March in Guangdong, and the possibility of the outbreak is high after the school opening.

Norovirus can easily be transmitted throughout the population, which means people of all ages can be infected.

The virus is highly infectious and can infect many people with just a few virus particles. As a result, clusters of norovirus infection are likely to occur in places where people gather, such as schools and nurseries.

People can be infected with the virus through multiple ways -- eating food or drinking water contaminated by the norovirus, exposure to aerosols produced by fecal matter or vomit of patients, or indirect contact with objects or the environment contaminated by vomit or excrement.

The virus can survive in the range of 0 C‐60 C, and ordinary hot water cannot kill norovirus. Also, 75% alcohol and hand sanitizer do not inactivate norovirus, the Guangdong CDC stated, noting that the virus can survive for two weeks on surfaces and more than two months in water.

According to the Guangdong CDC, the incubation period of norovirus infection is short, usually 12 to 48 hours. The most common symptoms of norovirus infection are vomiting and diarrhea, followed by nausea, abdominal pain, headache, fever, chills and muscle soreness. Vomiting is the main cause in children, and diarrhea is the main cause in adults.

The onset of norovirus infection is rapid and self-limited. Most patients can recover within 2 to 3 days after onset. A small number of infants and the elderly, especially those with underlying diseases, may suffer more serious symptoms such as dehydration and slow recovery.

East China's Jiangsu and Central China's Henan health authorities also released similar notice. 

They noted patients with norovirus gastroenteritis should be quarantined at home until two days after the symptoms disappear completely. The best way to prevent norovirus is to frequently wash hands and use disinfectant . Alcohol disinfection is not effective against norovirus and that chlorinated disinfectant is recommended.

Guangdong CDC also listed other possible virus infections. 

It said at present, the COVID-19 epidemic situation in the province is at a low level and stable.

In winter and spring, there is still a risk of sporadic human cases of avian influenza such as H5N6 and H9N2, and other less common subtypes of human avian influenza cannot be ruled out.

Recently, the proportion of influenza-like cases in Guangdong was lower than the baseline level, and no outbreaks of influenza-like cases and clusters of upper respiratory tract infections were reported.

But considering there is usually a peak of influenza in winter and spring in the province, Guangdong CDC said that with the beginning of the new semester in February, they would pay attention to the change in influenza activity level.

Global Times