Its transmission methods are multiple – fecal/oral route, person-to-person, touching contaminated objects, aerosolization!
It doesn’t have a lipid envelope so alcohol and many detergents don’t kill it.
It can live for 12 hours on hard surfaces and up to 12 days on fabrics. It can survive for months, even years in contaminated still water.
It spreads so rapidly that one outbreak at a scouting event in the Netherlands showed a phenomenal rate of transmission: each infected person quickly infected an average of 14 others before increased hygiene stopped its spread.1
Norovirus, derived from the Norwalk virus in the Caliciviridae family, affects 21 million Americans each year, causing 70,000 hospitalizations and 800 deaths.
It accounts for 90% of non-bacterial outbreaks of gastroenteritis around the world, according to the CDC.
With this virulence and transmission rate, what can you do to prevent its spread?
Knowing the Enemy
To combat norovirus-the most common cause of viral gastroentereritis-it’s important to know its symptoms and understand the implications of an outbreak.
Nausea, low-grade fever, forceful vomiting, watery diarrhea, abdominal pain and in some instances loss of taste are hallmarks of norovirus. It can also cause lethargy, weakness, muscle aches and headaches.
Norovirus, which includes Norwalk, Hawaii, Snow Mountain, Mexico, Desert Shield, Southampton, Wilkinson and Lordsdale viruses, can spread quickly from person to person in closed environments like long-term care facilities, day care centers, schools, hotels and cruise ships.
People get infected from contaminated liquids or foods, such as raw shellfish, leafy vegetables and fruits.
For example, when a food handler has the virus and does not wash his or her hands thoroughly after using the bathroom.
It is also transmitted by touching a contaminated surface or by direct contact with a person who has the virus.
Contagion begins the moment the person begins to feel sick to about 3 days after they recover, according to the CDC.
“Aerosolization transmission factors in when a patient vomits,” explained Carol McLay, DrPH, MPH, RN, CIC, chair of APIC’s Communications Committee and an infection prevention consultant out of Lexington, KY.
“There’s a great deal of force behind vomiting in norovirus. I recommend the toilet lid be closed when diarrhea or vomit is flushed down to prevent aerosolization,” she said.
Preventing the Spread
As previously noted, norovirus does not have an envelope, so many detergents and antiseptics won’t inactivate it.
“Alcohol-based hand cleaners are not effective against norovirus,” McLay confirmed. “Thorough hand-washing with soap and hot water is essential. Disinfection of surfaces in the home should include a bleach solution of 5-25 tablespoons per gallon of water; whoever cleans should always wear gloves.
“In healthcare settings, use EPA-approved disinfectants,” she continued. “Because the virus survives a long time on surfaces, it’s important the disinfectant remain on any surface for the recommended period of time.”
If an outbreak occurs, McLay said cleaning should be increased to twice a day on a unit. “High touch surfaces should be disinfected 3 times daily. Every surface should be cleaned from call bells, trays, beds, doorknobs; everything in the bathroom.”
If norovirus is suspected or confirmed, McLay recommends standard precautions and contact isolation with gown and gloves. “Staff should wear gowns and gloves when entering the room and a facemask if splashes are anticipated,” she said. “If the patient is vomiting, I would certainly wear a full face shield as well.”
In the past, the best way to control norovirus in a facility was by isolation – closing down a unit and then thoroughly cleaning it before reopening. However, new strategies recommend moving symptomatic patients to single rooms or bays that can be closed off. If more than two bays are affected, then the entire unit would be closed. With this new strategy only 54% of outbreaks caused an entire unit to be closed, compared to 90% when standard outbreak control measures were used.2
McLay recommends several actions to prevent or to stem an outbreak, including:
• “Communication: If a problem arises, contact your infection preventionist. It’s a good idea to contact the local health department which has a lot of resources your facility may not have.
• Testing: Send stool specimens to a lab promptly for confirmation.
• Enforce Contact Isolation: Isolate symptomatic patients from asymptomatic patients. If you don’t have private rooms, start cohorting patients with suspected norovirus in the same room. You may want to designate whole sections of your facility, separated from all other units, for patients with norovirus.
• Take Care of Staff: If some staff have recovered from recent norovirus infection, have them look after the symptomatic patients. The virus conveys a short-term immunity of perhaps 6 months. However, be aware there are several viruses in the norovirus group and a person can contract one type after having had another type.
• Suspend Activities: In a long-term care facility it is a good idea to suspend all group activities to minimize transmission.
• Emphasize Hand Hygiene: This rule applies to staff, visitors and patients.
• Limit visitors if deemed necessary.
• PPE: Ensure there is sufficient personal protective equipment in the facility during the outbreak.
• Defer admissions until the outbreak is over.
• Step up Cleaning: Clean the units at least twice a day. Patient rooms and all high-touch areas should be cleaned 3 times a day. This affects the number of environmental services staff you’ll need.
• Educate Staff: Make sure staff who are ill go home immediately. Recommend they stay home until symptoms have resolved for at least 48 hours. Be aware absences due to illness can be as long as five days.
• Limit Interaction: Exclude any nonessential staff from the affected units.
• Be Proactive: In winter, there is a high index of suspicion that it’s norovirus if a facility has patients with gastrointestinal distress. If other facilities in the area have an outbreak, it’s just a matter of time before your facility will be affected. Put protective measures in place to prevent the spread. To prevent spread to your facility communicate, stress fastidious hand hygiene and limit visitors.”
As McLay points out: “It only take 18 particles to cause a norovirus infection and when a person is at peak shedding of the virus there are more than 5 billion infectious doses in each gram of feces. Take every case seriously and act quickly.”
References for this article can be accessed here.
Gail O. Guterl is a freelance writer.