Gastroenteritis means inflammation of the stomach and intestines. It may be caused by infection by certain bacteria, viruses or parasites. It may also be caused by certain medications or medical conditions.

Viral gastroenteritis is an infection caused by viruses that result in vomiting, diarrhoea or abdominal cramps. It is sometimes called “gastric flu” although it is not related to influenza. Many different viruses can cause gastroenteritis, including rotaviruses, noroviruses, adenoviruses, sapoviruses and astroviruses.

The main symptoms of viral gastroenteritis are watery diarrhoea and vomiting. The affected person may also have headache, fever and abdominal cramps. In general, the symptoms begin 1 to 2 days following infection and may last 1 to 10 days, depending on the which virus causes the illness.

Noroviruses are a group of viruses that cause viral gastroenteritis. Noroviruses were formerly called “Norwalk-like viruses”.

Viruses are different from bacteria, some of which can cause illness similar to norovirus infection. Viruses are much smaller, are not affected by treatment with antibiotics, and cannot grow outside of a person’s body.

Symptoms usually include nausea, vomiting, diarrhoea, and abdominal cramps. Headache, muscle aches, and a general sense of tiredness are also fairly common. Low-grade fever is present in about half of cases. The illness begins suddenly and is usually brief, lasting about 1 or 2 days. In general, children experience more vomiting than adults.

Norovirus gastroenteritis is usually not serious, although people may feel very sick and vomit many times a day. Most people get better within 1 or 2 days, and they have no long – term health effects arising from their illness.

Sometimes people are unable to drink enough liquids to replace the liquids they lost due to vomiting and diarrhoea. They become dehydrated and may need medical attention. Dehydration is usually only seen among the very young, the elderly and persons with weakened immune systems.

There is no evidence that an infected person can become a long – term carrier of norovirus.

Noroviruses are found in the stool or vomit of infected people. People can become infected with the virus in several ways, including:

• Eating food or drinking liquids that are contaminated with norovirus.
• Touching surfaces or objects contaminated with norovirus, and then placing their hand in their mouth. Surfaces and objects can be contaminated with either vomitus or faecal matter. Noroviruses can also spread via a droplet route from vomitus. These viruses are relatively stable in the environment and can survive freezing and heating to 60 deg C.
• Having direct contact with another person who is infected and showing symptoms (for example, when caring for someone with illness, or sharing foods or eating utensils with someone who is ill).

Persons working in day care centres or nursing homes should pay attention to children or residents who have norovirus illness. This virus is very contagious and can spread rapidly.

Symptoms usually appear about 12 to 48 hours after ingestion of the virus.

Norviruses are very infectious and can spread easily from person to person. Both stool and vomit are infectious.

People infected with norovirus are infectious from the time they begin feeling ill to at least 3 days after recovery. It is therefore very important for people who have recently recovered from norovirus illness to practice good hygiene such as frequent handwashing.

Anyone can become infected with noroviruses. Due to differences in genetic factors, some people are more likely to become infected and develop more severe illness than others.

Routine testing for norovirus is usually not necessary. Your doctor will recommend the appropriate laboratory tests based on your clinical condition. MOH does collect samples to test for norovirus for the purpose of disease surveillance and outbreak investigations. If approached by MOH or other medical staff for this purpose, we will greatly appreciate your cooperation.

There are many different strains of norovirus and this makes it difficult for a person’s body to develop long – lasting immunity. Therefore, norovirus illness can recur throughout a person’s lifetime.

There is currently no antiviral medication that works against noroviruses. There is also no vaccine to prevent infection. Norovirus infection cannot be treated with antibiotics. This is because antibiotics work against bacteria, not viruses.

Norovirus gastroenteritis is usually brief in healthy persons. When people are ill with vomiting and diarrhoea, they should drink plenty of fluids to prevent dehydration. Dehydration among young children, the elderly, and the sick can be common, and it is the most serious health effect that can result from norovirus gastroenteritis. By drinking oral rehydration fluids, juice, or water, people can reduce their chance of becoming dehydrated. Sports drinks do not replace the nutrients and minerals lost during this illness. Persons who become dehydrated because they are unable to drink enough fluids to replace the liquids they lost because of vomiting and diarrhoea should seek medical attention.

Yes. You can decrease your chance of coming in contact with norovirus by following these preventive steps:

• Frequently wash your hands, especially after toilet visits and changing diapers and before eating or preparing food.
• Carefully wash fruits and vegetables, and steam oysters before eating them.
• Thoroughly clean and disinfect contaminated surfaces immediately after an episode of illness by using household bleach in a ratio of one unit to 50 units of water
• Immediately remove and wash clothing or linens that may be contaminated with virus after an episode of illness (use hot water and soap)
• Flush or discard any vomitus and/or stool in the toilet and make sure that the surrounding area is kept clean.

Persons who are having symptoms suggestive of viral gastroenteritis should also refrain from attending school or work until they are well.

Persons who are ill with viral gastroenteritis should not prepare food while they have symptoms and for three days after they recover from their illness. They should continue to maintain good hand hygiene after that as some persons may continue to excrete virus for up to 2 weeks. Food that may have been contaminated by an ill person should be disposed of properly.

You can teach your child to adopt preventive measures like frequent washing of hands and other hygienic practices. The school would also have been advised on other measures to take to safeguard the health of your child. Please follow the advice of the school authorities closely. If s/he develops symptoms suggestive of norovirus gastroenteritis, please consult a medical practitioner.

Schools have been advised to adopt precautionary measures and enhance their surveillance for viral gastroenteritis amongst their students. The Ministry of Health is closely monitoring the situation with the Ministry of Education.