Food Recall Resource

Norovirus Infection: What It Does to Your Body and How to Prevent It

From a self-limiting infection to causing potentially fatal complications, norovirus can be a killer in disguise. Here’s how you can prevent it.

On February 2018, norovirus spread like crazy during the PyeongChang Winter Olympics in South Korea. The Korean Centers for Disease Control and Prevention (KCDC) reported that the virus affected nearly a hundred people. These included security staff, members of the PyeongChang Olympics Organizing Committee, venue personnel, cafeteria workers, and athletes.

Well, Olympics are not only the breeding ground for this rapidly spreading viral infection. Healthcare facilities, restaurants, schools, and cruise ships are equally at the risk of a norovirus outbreak, according to the Centers for Disease Control and Prevention (CDC).

What is Norovirus?

Norovirus (also called the “Norwalk agent”) is a type of virus that can cause sudden episodes of severe vomiting and diarrhea. Some people call it the “winter vomiting bug”.

When the virus enters into the body, it causes inflammation of the stomach and intestines. This is called gastroenteritis or the stomach flu. Norovirus is notorious for causing gastroenteritis in millions of people across the globe. In fact, it is the leading cause of nonbacterial gastroenteritis globally.

While norovirus infection is generally mild that tends to go away on its own within a few days, some people may experience severe diarrhea and vomiting for a longer duration. The people at high risk of developing severe norovirus symptoms include – infants, older adults and those with weakened immune systems.

Norovirus Symptoms

People who have eaten contaminated food or have drunk contaminated water typically develop the symptoms within the next 24 to 48 hours. The duration from the entry of a microorganism into the system and appearance of the symptoms is called the incubation period. Therefore, the incubation period of norovirus is 24 to 48 hours.

In healthy adults, the symptoms last one to three days. Among young kids, elderly people, and hospitalized patients, it can last 4-6 days. However, in those with weakened immune systems, the symptoms can linger for a few weeks to years.

Vomiting is the first sign of the infection, which may be followed by:

  • Stomach cramps
  • Fever (in up to half of the cases)
  • Watery diarrhea
  • Headache
  • Chills
  • Muscle pain

On examination, your doctor may also notice increased heart rate and low blood pressure caused by the loss of fluids from the body.

Causes of Norovirus Infection

Norovirus is highly contagious, meaning it can readily spread from one person to another. As with other foodborne illness, the major methods of transmission are:

  • Eating virus-tainted food
  • Drinking contaminated water
  • Touching surfaces or objects that have been touched by an infected person
  • Close contact with the infected person

Norovirus Treatment: What are Your Options?

Unlike in bacterial infections of the stomach, antibiotics are not useful in treating viral infections. In addition, no specific treatment has proven benefits in treating the infection.

Interestingly, there have been reports of successful treatment of norovirus infection by an antiprotozoal medication – nitazoxanide (Brand name: Alinia). However, conclusive results are not available.

Treatments are supportive and aim at preventing dehydration and restoring normal fluid and electrolyte balance in the body. Most people obtain a complete recovery within a few days with supportive treatments.

Severe vomiting may prevent some people from drinking enough water. In such cases, the doctor may inject fluids through a vein.

Other treatments may include – medications to relieve nausea and vomiting, and headache and/or muscle pain.

Agents that decrease the frequency of bowel movements may be recommended in severe diarrhea. However, you should never use such medications if you have infectious diarrhea.

Norovirus Complications

In most cases, norovirus infection is mild and quite unlikely to cause fatal complications. Nonetheless, in immunocompromised patients, it may lead to death due to malnutrition, dehydration, and changes in the linings of the intestinal tract. The same may be true for young children.

It is therefore critically important to keep a close eye on the signs of dehydration, which include:

  • Excessive weakness
  • Dry mouth and throat
  • Dizziness
  • Severely decreased urine volume or frequency

Severely dehydrated children may have few or no tears while crying.

Norovirus Prevention

Proper hand washing and safe food handling are the two indispensable parts of the norovirus prevention strategy.

  • Make sure to wash your hands using a soap and water after using the bathroom and changing diapers.
  • Do not eat or drink contaminated food or water. If someone in your family has the infection, do not let him/her cook during and at least two days after the illness.
  • Eat fruits and vegetables that have been properly washed.
  • Cook oysters and other shellfish at a temperature higher than 140°F.
  • Disinfect contaminated objects or surfaces such as clothing or linens. Use gloves while disinfecting.
  • If you have contracted the virus, take a leave from your work. This is even more important if your work involves food handling. Kids with infection should not resume their school until two days have passed since the disappearance of symptoms.

Top 10 Interesting Facts about Norovirus

  1. Norovirus is the number one cause of diarrhea and vomiting associated with viral gastroenteritis (infectious diarrhea that causes inflamed stomach and intestines) affecting 19 to 21 million Americans each year.
  2. Each year, it causes 570 to 800 deaths in the US.
  3. It is responsible for more than half of all cases of foodborne illness globally.
  4. The annual economic burden of norovirus infection is approximately $2 billion.
  5. In the US, the duration from November to April is the most likely to have norovirus outbreaks. Nonetheless, you can contract the illness at any time of the year.
  6. According to one study in the Journal of Occupational and Environmental Hygiene, germ-carrying objects account for 25% to 82% of illnesses in a norovirus outbreak.
  7. Norovirus vaccine is currently in the early phase of development. As of now, there are no vaccines or specific antiviral drugs to prevent or fight the infection.
  8. Humans are the only species that carry this virus. However, it is emerging that some animal may also harbor the virus.
  9. Norovirus can survive extreme temperatures, from freezing to 140°F and most disinfectants.
  10. Due to the lack of long-term immunity and emerging new strains of the virus, you may contract the illness multiple times throughout your life.
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