In the United States, norovirus (or Norwalk virus) is the among the leading causes of illness and outbreaks from contaminated foods. Many of us know of this virus as the “cruise ship virus”. This is due to the fact that the virus flourishes in close, contained quarters. In fact, outbreaks on cruise ships only account for 1 percent of all reported cases. Norovirus can appear any time after consuming contaminated food or water, but most symptoms appear 12 to 48 hours later. Norovirus is highly contagious. The CDC estimates that each year in the United States norovirus causes 19 to 21 million illnesses, 56,000 to 71,000 hospitalizations, and 570 to 800 deaths. In fact, it is estimated that people can contract this virus up to five times in their lifetime.
What is Norovirus?
Norovirus is “any of a genus of small, round, single-stranded RNA viruses that includes a single species (Norwalk virus) with various strains causing gastroenteritis in people and animals.” Of more interest are what the virus can do to our bodies, and how this virus is spread.
Norovirus can be found in foods such as leafy greens, fresh fruits, and shellfish (such as oysters). It can also be present in contaminated water. Although the most publicized outbreaks of this virus are associated with cruise ships, noroviruscan occur in day care centers, nursing homes, and schools: anywhere where conditions are crowded and transmission is more likely. According to the CDC’s National Outbreak Reporting System, schools and daycare settings, health care facilities, private residences and other make up approximately 19 percent of reported outbreaks. Banquet and catering facilities comprise 17 percent. Restaurants 64 percent of the remaining outbreaks.
What are the Symptoms of Norovirus?
- Abdominal pain or cramps
- Watery or loose diarrhea
- Low-grade fever
- Muscle pain
Norovirus symptoms usually begin with vomiting and/or diarrhea, and alleviate within one to three days. But an infected person may still shed the virus in their feces for up to two weeks. Infants and young children, the elderly, and persons with immune-compromised diseases should be vigilant if they have contracted this virus as severe dehydration can occur, resulting in hospitalization. Warning signs of dehydration include fatigue, dry mouth, listlessness, dizziness, and decreased urine output. Infants and young children may cry with no tears and be very fussy or very sleepy. Always seek immediate medical attention if you have diarrhea that doesn’t go away after a few days, severe vomiting, bloody stools, and any of the aforementioned symptoms of dehydration.
How Does Someone Become Sick with Norovirus?
Norovirus is usually spread by the fecal–oral route, and typically through a sick food service worker. Some methods of transmission include:
- Eating contaminated food
- Drinking contaminated water
- Through person-to-person contact
- From contaminated surfaces
How is Norovirus Diagnosed and Treated?
Doctors can diagnose norovirus based upon your symptoms or a stool sample. Treatment involves rest and fluids to replenish those lost through vomiting and diarrhea. But if you’re unable to “hold anything down”, intravenous fluids are recommended. Also, you may need to take anti-diarrheal medication, but only with the approval of your health care provider, especially if you are over the age of 65.
If you have young children or infants at home, commercial oral hydration solutions such as Pedialyte are a good choice. On the other hand, drinks that contain a lot of sugar, such as fruit juices or fruit drinks can actually worsen diarrhea. Adults, however, can drink oral hydration solutions like Gatorade.
To alleviate the frequency of vomiting and diarrhea, consuming bland foods can help:
- Starches and cereals, such as potatoes, noodles, rice or crackers
- Broiled vegetables
Why is Norovirus So Prevalent with Restaurants?
One of the most significant causes of norovirus contamination originates from the food service industry. What is particularly disturbing about this fact is that food service workers often report to their jobs when they are sick, increasing the risk of contaminating the food that they handle. One in five food service workers have reported working while sick with vomiting and/or diarrhea, fearing the possibility of losing their jobs or leaving their coworkers short-staffed. Of the outbreaks associated with food service workers, ready-to-eat foods (those served without additional preparation), such as raw vegetables, salads, and baked goods account for 54% of norovirus infections from workers touch or handle these foods with their bare hands. Of even greater concern is that observation of these food service workers revealed that they washed their hands only one in four times that they should. To compound this problem, norovirus is very difficult to kill, and remains potentially infectious on foods at freezing temperatures and until heated above 140 degrees Fahrenheit. Additionally, the virus can remain on countertops and serving utensils for up to two weeks. Even hand sanitizers can be ineffective.
What are Public Health Agencies Doing?
At the federal government level, foodborne pathogens and their outbreaks are obvious causes for concern. Federal agencies are working with state and local agencies to encourage the adoption and effective implementation of all FDA Food Code provisions. Additional funding, however, is critical for the detection, response, investigation, and reporting of norovirus outbreaks. While not currently addressed to a great extent in recent reports, the addition of block chain technology may exponentially assist in determining the source of outbreaks so that appropriate recalls are issued more rapidly. With regard to the food service industry, manufacturers, vendors, and distributors of food products can insist on food safety laws and regulations, certify that kitchen managers thoroughly train food service workers in food safety practices, establish work policies that require workers to stay home when ill with gastrointestinal symptoms and for at least 48 hours after their symptoms resolve. As for the food workers, it should be a standard and almost reflex practice to wash hands often with soap and water for a minimum of 20 seconds, use utensils and disposable gloves when touching ready-to-eat foods with bare hands, clean and sanitize kitchen surfaces using sanitizers approved by the EPA for use against norovirus, washing all produce, and never serving undercooked (below 140 degrees Fahrenheit) shellfish.
Can Norovirus Be Prevented?
Norovirus is highly contagious. It only takes an extremely small amount to become sick. In fact, the amount of virus particles on the head of a pin would be enough to sicken about 1,000 people. To help prevent the spread of this potent virus, you can:
- 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 until symptoms are gone.
- Avoid traveling until signs and symptoms have ceased.