Updated Norovirus Outbreak Management and Disease Prevention GuidelinesRegister Today!
- by brian Mar 4, '11cdc stresses hand washing to prevent norovirus infections
the cdc, in updated guidelines, underscored that hand hygiene is the key to prevent norovirus infections, noting that use of soap and water is a more proven strategy than the use of alcohol-based hand sanitizers. infected patients can be isolated under the care of a nursing staff, but asymptomatic people should not be taken to infection-free units until two days after exposure to the virus, the agency recommended.
noroviruses are the most common cause of epidemic gastroenteritis, responsible for at least 50% of all gastroenteritis outbreaks worldwide, and a major cause of foodborne illness. in the united states, approximately 21 million illnesses attributable to norovirus are estimated to occur annually. since 2001, when the most recent norovirus recommendations were published (cdc. "norwalk-like viruses." public health consequences and outbreak management. mmwr 2001;50[no. rr-9]), substantial advances have been made in norovirus epidemiology, immunology, diagnostic methods, and infection control. as molecular diagnostic techniques have improved in performance and become more widely available, detection and reporting of norovirus outbreaks have increased. although the inability to culture human noroviruses in vitro has hampered progress, assessment of the performance of disinfectants has been facilitated by the discovery of new, cultivable surrogates for human noroviruses. in addition, the periodic emergence of epidemic strains (from genogroup ii type 4, gii.4) and outbreaks in specific populations (e.g., the elderly in nursing homes) have been characterized. this report reviews these recent advances and provides guidelines for outbreak management and disease prevention. these recommendations are intended for use by public health professionals investigating outbreaks of acute gastroenteritis, including state and local health authorities, as well as academic and research institutions.
noroviruses cause acute gastroenteritis in persons of all ages. the illness typically begins after an incubation period of 12--48 hours and is characterized by acute onset, nonbloody diarrhea, vomiting, nausea, and abdominal cramps. some persons might experience only vomiting or diarrhea. low-grade fever and body aches also might be associated with infection, and thus the term "stomach flu" often is used to describe the illness, although there is no biologic association with influenza. although symptoms might be severe, they typically resolve without treatment after 1--3 days in otherwise healthy persons. however, more prolonged courses of illness lasting 4--6 days can occur, particularly among young children, elderly persons, and hospitalized patients (17,18). approximately 10% of persons with norovirus gastroenteritis seek medical attention, which might include hospitalization and treatment for dehydration with oral or intravenous fluid therapy (7,19,20). norovirus-associated deaths have been reported among elderly persons and in the context of outbreaks in long-term--care facilities (21,22). necrotizing enterocolitis in neonates, chronic diarrhea in immunosuppressed patients, and postinfectious irritable bowel syndrome also have been reported in association with norovirus infection (23--25); however, more data from analytic studies are needed to confirm a causal link with these conditions.
norovirus is shed primarily in the stool but also can be found in the vomitus of infected persons, although it is unclear if detection of virus alone indicates a risk for transmission. the virus can be detected in stool for an average of 4 weeks following infection, although peak viral shedding occurs 2--5 days after infection, with a viral load of approximately 100 billion viral copies per gram of feces (26). however, given the lack of a cell culture system or small animal model for human norovirus, whether these viruses represent infectious virus is unknown, and therefore the time after illness at which an infected person is no longer contagious also is unknown. furthermore, up to 30% of norovirus infections are asymptomatic, and asymptomatic persons can shed virus, albeit at lower titers than symptomatic persons (26--28). the role of asymptomatic infection in transmission and outbreaks of norovirus remains unclear.
long-term care and other health-care facilities
health-care facilities including nursing homes and hospitals are the most commonly reported settings of norovirus outbreaks in the united states and other industrialized countries (59,60,63--65). virus can be introduced from the community into health-care facilities by staff, visitors, and patients who might either be incubating or infected with norovirus upon admission or by contaminated food products. outbreaks in these settings can be prolonged, sometimes lasting months (66). illness can be more severe in hospitalized patients than for otherwise healthy persons (18), and associated deaths have been reported (21,22). strict control measures (including isolation or cohorting of symptomatic patients, exclusion of affected staff, and restricting new admissions into affected units) are disruptive and costly but might be required to curtail outbreaks (9,67,68).
link to the full cdc guidelines:
the attached file is the full updated guidelines in pdf format for easy printing.Last edit by brian on Mar 4, '11
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- Mar 5, '11 by tewdlesPretty sure at least two of my peers have been out w/ this in recent weeks...
- Mar 5, '11 by netglowGot this in school from a hospital that had an outbreak. Got it bad. Woke up in the middle of the night having dreamed that I had to leave the group of people I was with in my dream, because I was very ill. I awoke with just enough time to turn my head and barf while supine. I almost aspirated. Hours of continuous misery of vomiting/diarrhea often at the same time put me in the ER for a few bags.
I am a (normally) healthy person. Noro can be very bad.
- Got it in a nursing home a few years ago despite using gloves and taking precautions. Onset was quite sudden, and like the last poster, I was sleeping and woke up with all the horrible symptoms. There were six rooms in that nursing home in one hallway where the infections first occurred, but soon even the administative staff came down with it. It was a major outbreak in that facility.
They don't say anything in this article about the possibility air borne transmission but I do remember reading once about diners in a restaurant being infected at tables nearby where someone had been ill when they were present. Wish I could find that link. Given the violence of the projectile vomiting with these cases, I would not be surprised to find that some viral particles were aerosolized. It's an interesting thought...
Certainly, hand washing is the best way to help prevent it, but also trying to keep these patients in just one area, and with the same staff to help avoid infecting other units. Most nursing homes will try to keep the patients in their rooms, disinfect door knobs and sink faucets (in older facilities that have them) frequently. I NEVER used the ice machines in any of those facilities either.
- Here is a link that mentions airborne transmission. I really do believe that this happens. It has to.
Wearing masks is important but not usually done. I made my night staff do this last year, and none of them got infected on my shift from whatever was causing the outbreak.
Quote from www.publichealthmdc.comControl of transmission at the ward level
• Unfortunately, by the time the outbreak has been recognized on a ward, it is likely the majority of susceptible patients and staff on duty may have been exposed to the infected agent, particularly if vomiting is a widespread symptom.
• Gloves, masks and gowns should be worn whenever contact with an infected patient or contaminated environment is anticipated.
• Affected wards or floors should be closed to new admissions and visitors to prevent the introduction of other susceptible individuals.
• "Airborne" transmission may be a significant contributor to the number of cases since projectile vomiting could potentially create infectious aerosols. Air currents generated by open windows or air conditioning could disperse aerosols widely. Air currents should be minimized.
• Affected wards should remain closed until a 48-hour period has passed with no new cases among patients or staff.
• Non-essential staff should be excluded from affected clinical areas.
Quote from virology-online.comDiarrhoeal viruses are mainly spread by the faecal-oral route, either through infected foods such as shellfish or through an infected food handler. However, other modes of transmission are thought to be possible, in particular through aerosol sprays set up by vomitus. Food could be contaminated by this means or the viruses could be inhaled by other persons. noroviruses have in particular been associated with airborne transmission.
The first aspect of control must be to interrupt person to person transmission. This may be very difficult in view of the information emerging about airborne transmission. Personal hygiene for both staff and patients should be emphasized, particularly hand washing. Prompt removal of vomitus and diarrhoea is important in order to reduce the chance of environmental contamination. The area should be disinfected by chlorox after cleaning. Affected persons should be isolated or cohorted together. This may be difficult in such a large outbreak. Any staff taken ill should refrain from coming to work. Transfer of staff from ward to ward should be avoided since this may spread infection to other wards. Since noroviruses may be spread through aerosols, it may be prudent to use respiratory precautions such as the use of facemasks for staff and visitors. If the outbreak cannot be controlled, then it may prove to be necessary to close down affected wards, services, or even the whole hospital.
- Mar 6, '11 by GadgetRN71I just had this last week- OMG, I thought I was dying. Hit very suddenly. Interesting fact that alcohol based sanitizers don't do much, hooray for good old fashioned hand washing.
- Mar 7, '11 by indigo girlQuote from GadgetRN71I just had this last week- OMG, I thought I was dying. Hit very suddenly. Interesting fact that alcohol based sanitizers don't do much, hooray for good old fashioned hand washing.
oh, you are so right about that! You do think that you are going to die or wish you were! Yes, to soap and water!
- Mar 7, '11 by April, RNThere is an outbreak in my area. My family is just getting over it. Lots of co-workers have had it. Schools, hospitals, kids' birthday parties... seems like we can't get away from vomiting and diarrhea no matter where we go lately!