Winter Vomiting Bug (Norovirus) Spread, Symptoms, Treatment

Americans traveling to the United Kingdom may hear about outbreaks of the winter vomiting bug. It may sound puzzling and even dangerous but the winter vomiting bug is just a viral gastroenteritis caused by noroviruses. The infection can occur at any time of the year although it tends to be more prominent during winter, hence the common name. As with any other acute tummy bug infection, it can lead to serious consequences if complications like dehydration are not prevented or treated appropriately.


What is the winter vomiting bug?

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As mentioned, the winter vomiting bug is a viral gastroenteritis caused by noroviruses. Gastroenteritis is a condition where the stomach and bowels become inflamed. It can be caused by a number of different factors but infections are the main cause. Most cases of infectious gastroenteritis are due to viruses with bacteria being the second most common cause. Viral gastroenteritis may be caused by a number of different families of viruses. It is also commonly referred to as the stomach virus, stomach flu or stomach bug. Since it is a viral infection there is no need for specific treatment and antibiotics will not work against the virus.

The winter vomiting bug is an acute viral infection. It starts suddenly and persists for a short period of time before resolving on its own, often without treatment. This type of infection can occur at anytime of the year but it tends to be more common in winter. Viral gastroenteritis caused by noroviruses is the most common type of viral gastroenteritis in the United Kingdom. However, noroviruses are present throughout the world. Although it is usually not serious, it tends to be more severe in certain vulnerable groups like babies, people with weakened immune systems and the elderly.

Causes and Spread

Winter vomiting bug is caused by noroviruses and there are about 25 different strains of this virus family that can infect humans. The condition is very contagious. Infected people are most contagious while ill and for a few days after they recover. However, a person is also contagious in the 12 to 48 hour incubation period and for 2 weeks or even longer after the symptoms resolve. The norovirus can be spread through several routes:

  • Contact with an infected person.
  • Contaminated food and water.
  • Inanimate objects (fomites) that are contaminated.

It is often spread through the fecal and vomit particles that may either be transferred directly from the infected person, through food and water that is contaminated or even by minute particles on surfaces such as door handles. Since the norovirus is easily passed between people, it is therefore understandable why outbreaks may occur within institutions like nursing homes, daycare centers, hospitals and schools. It can just as easily be passed among members of a household when one person is infected.

Signs and Symptoms

The incubation period for any infection is the time period from when a person become infected to the point when the symptoms of the infection commence. For the winter vomiting bug this is anywhere between 12 to 48 hours. After this period ends the signs and symptoms of the norovirus infection becomes evident. It includes:

  • Vomiting, usually with intense nausea.
  • Diarrhea, often explosive watery stool.
  • Abdominal cramps and stomach pain.
  • Headaches.
  • Fever.
  • General body aches.

The symptoms often arise suddenly and the vomiting and diarrhea are typically severe for the 2 to 3 days that it persists. The vomiting usually subsides first and abnormal bowel movements tend to persist for a longer period. There is copious loss of water and electrolytes as a result of the vomiting and diarrhea. If there is inadequate replenishment then dehydration may set in. Spotting the signs and symptoms of dehydration is important as it can be a potentially fatal complication if left untreated. Mouth dryness, thirst, dry skin, reduced urine output, excessive sleepiness and disorientation  are some of the signs of dehydration that needs to be identified early.

Treatment and Prevention

There is no specific treatment that is required for the viral infection. The main symptoms spontaneously resolve within 2 to 3 days but medication like acetaminophen can be used to treat the fever and pain. The focus should be on preventing dehydration and treating it once it has developed. This requires the use of oral rehydration solutions (ORS). However, if dehydration has developed and is severe, or if profuse vomiting impairs oral rehydration then hospitalization is necessary for intravenous (IV) administration of fluids and electrolytes. It is important to return to a diet of solid foods once the vomiting eases or stops entirely. Oral rehydration solution is not sufficient nutrition on its own.

Most people develop short-term immunity to the norovirus after an infection. This immunity only lasts for a few years and it is therefore not uncommon to suffer with a norovirus infection several times in life. The better option for prevention, rather than relying on immunity, is to take the necessary measures to minimize the chance of infection. This involves simple steps and habits such as:

  • Regularly wash hands especially before eating and after touching a person who is infected. An antiseptic soap is preferable but thoroughly washing with regular soap and water is also effective.
  • Do not share towels or any other personal items that may make contact with the mouth or nose. Even though a person may not seem like they have the infection or that they have recovered, they may still be contagious and the virus could be transmitted through these items.
  • Disinfect surfaces which an infected person has touched. This is only necessary for the symptomatic period when vomiting and diarrhea are present as vomitus and fecal particles can spread the virus.
  • Avoid leaving the house during the symptomatic period in particular. This will help to limit the spread of the infection to others. Furthermore the bed rest will assist with a faster recovery.
  • Seek medical treatment as soon as possible, especially if there are signs of dehydration that are not abating with oral rehydration. This can prevent more serious complications from arising.
  • Infected people should minimize contact with the elderly, babies or any person who has other health conditions as these individuals are prone to a more severe infection and complications which could become life-threatening.

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