Norovirus
Introduction
Noroviruses are a common cause of travellers’ diarrhoea.
Noroviruses are a group of viruses that cause winter vomiting disease, summer vomiting disease, Norwalk virus disease or epidemic viral gastroenteritis. They occurs worldwide and affects all age groups.
Noroviruses are spread directly between people or by consuming food and water contaminated with the virus particles. Contamination of surfaces (for example, door handles or tables) by virus particles can also lead to infection – during eating or drinking hands that have touched these surfaces transfer the virus into the mouth.
Noroviruses are highly infectious. Those infected shed billions of virus particles in their vomit and diarrhoea. Only a small number of particles are needed to cause infection. Shedding of viruses may continue after symptoms have resolved, usually for 48 to 72 hours, but it may be longer.
Norovirus infection can very quickly spread in places such as nursing homes, hospital wards, children's nurseries and schools, and on cruise ships.
The Illness
Symptoms usually start 12 to 48 hours after the virus enters the body. Symptoms start suddenly and include projectile vomiting, watery non-bloody diarrhoea, abdominal cramps, nausea and sometimes a mild fever. Vomiting is more common in children. Symptoms last for 1 to 3 days and then resolve.
Most people make a full recovery. Infants, the elderly and those with other health problems may require medical attention due to the risk of dehydration.
Treatment
No treatment can cure the infection. Instead treatment consists of relieving the symptoms and replacing the fluids lost by vomiting and diarrhoea. This can be done by drinking fluids or re-hydration solution or in severe cases by intravenous infusion in hospital.
Antibiotics have no effect on this illness as it is caused by a virus.
There is no vaccine against norovirus infection.
Recommendations for Travellers
Norovirus infection is a risk worldwide, and particularly during cruise travel.
The risk of norovirus infection can be reduced by practicing strict food and water hygiene and personal hygiene. All travellers should take precautions to ensure that all food and water consumed is safe.
- Hands should be washed with soap and water prior to handling food, eating and always after using the toilet.
- Shellfish should be thoroughly cooked before being eaten. Raw fruit and vegetables should be peeled prior to consumption.
- Contact with travellers with symptoms of norovirus infection should be limited to avoid infection.
- If caring for, or in contact with an individual with norovirus infection, careful handling of potentially infectious material is essential. This includes safe disposal of vomit/diarrhoea, soiled clothing, bedding, unfinished food, crockery and cutlery.
- All contaminated surfaces must be thoroughly cleaned and disinfected using a bleach based household cleaner.
Handwashing facilities may be poor or not available when travelling, therefore it is advisable to carry sanitising gel or hand wipes at all times.