What is norovirus?
This is the most common cause of upset stomach.
It’s sometimes called “small round structured virus” (SRSV) or “Norwalk-like virus”. However, most people are familiar with it as “the winter vomiting bug” because they’re most likely to catch it during the winter months.
Norovirus infection can occur at any time of the year. And the NHS estimates that between 600,000 and one million people get it in the UK in any one year.
You may become aware of outbreaks of the norovirus in news reports of large groups of people becoming ill, for instance in hospitals, schools or on cruise ships.
Outbreaks of norovirus in hospitals usually lead to ward closures and visiting time restrictions.
Signs and symptoms of norovirus infection include:
- Abdominal pain or cramps
- Watery or loose diarrhea
- Low-grade fever
- Muscle pain
Signs and symptoms usually begin 12 to 48 hours after first exposure to the virus and last one to three days. You may continue to shed virus in your feces for up to two weeks after recovery.
Viral shedding may last several weeks to several months if you have an underlying health condition.
Some people with norovirus infection may show no signs or symptoms. However, they are still contagious and can spread the virus to others.
When to see a doctor
Seek medical attention if you develop diarrhea that doesn’t go away within several days.
Also call your doctor if you experience severe vomiting, bloody stools, abdominal pain or dehydration.
What causes it?
The virus can be transmitted by contact with contaminated surfaces or objects, contact with an infected person, or by the consumption of contaminated food or water.
The bacteria can live on surfaces for up to five days and is impossible to spot.
Places such as train carriages, buses or offices are hotbeds for them – so much so, that experts encourage anyone who thinks they might be carrying the bug to stay away from built-up areas.
Risk factors for becoming infected with norovirus include:
- Eating in a place where food is handled with unsanitary procedures
- Attending preschool or a child care center
- Living in close quarters, such as in nursing homes
- Staying in hotels, resorts, cruise ships or other destinations with many people in close quarters
- Having contact with someone who has norovirus infection
For most people, norovirus infection clears up within a few days and isn’t life-threatening. But in some people — especially children and older adults with compromised immune systems in hospitals or nursing homes — norovirus infection can cause severe dehydration, malnutrition and even death.
Warning signs of dehydration include:
- Dry mouth and throat
- Decreased urine output
Children who are dehydrated may cry with few or no tears. They may also be unusually sleepy or fussy.
Norovirus infection is highly contagious, and anyone can become infected more than once. To help prevent its spread:
- Wash your hands thoroughly, especially after using the toilet or changing a diaper.
- Avoid contaminated food and water, including food that may have been prepared by someone who was sick.
- Wash fruits and vegetables before eating.
- Cook seafood thoroughly.
- Dispose of vomit and fecal matter carefully, to avoid spreading norovirus by air. Soak up material with disposable towels, using minimal agitation, and place them in plastic disposal bags.
- Disinfect virus-contaminated areas with a chlorine bleach solution. Wear gloves.
- Stay home from work, especially if your job involves handling food. You may be contagious as long as three days after your symptoms end. Children should stay home from school or child care.
- Avoid traveling until signs and symptoms have ended.
If you have developed norovirus, you should avoid contact with others for at least 48 hours after your symptoms have gone.
How can norovirus be treated?
Norovirus can’t be “cured” and there are no specific medicines that can be taken if you catch the “winter vomiting bug”. The usual advice is to let the illness “run its course”.
Make sure you drink plenty of water to replace the fluids lost from your body through diarrhea and vomiting. This is particularly important for young children and the elderly.
If you feel like eating, choose foods that can be easily digested.
Will we find a cure?
Scientists have developed a ‘vomiting robot’ to help detect how far microscopic particles of sick can carry the virus.
According to Prof Ian Goodfellow, who has spent 10 years trying to cure norovirus, the speed at which it can spread makes the bug ‘the Ferrari of the virus world’.