Presentation on theme: "Prepared by Erva-Jean Stevens"— Presentation transcript:
1Prepared by Erva-Jean Stevens CONTROL OF NOROVIRUSPrepared by Erva-Jean Stevens(PhD Candidate)Walden UniversityEnvironmental HealthOctober, 2010Hello everyone. My name is Erva Jean Stevens and I am currently enrolled in the PhD in Public Health Programme at Walden University. The topic of interest this morning is Norovirus control specific to hotels. This presentation is being made to the 3rd year students at the University of Technology, Jamaica who are enrolled in the Public Health Inspection Program.
2Outline Objectives What is Norovirus Transmission of norovirus Signs and symptomsCharacteristics of norovirusCase study- presentation of cases- preliminary investigationsThe presentation involves introduction and objectives, we will then look at the transmission, signs and symptoms and characteristics of norovirus. We will then look at a case study for an outbreak that occurred in a hotel in Jamaica in 1995.
3Outline cont’d -laboratory findings - management and control - challenges- outcomeControl – prevention of transmissionBarriers to effective controlControlReferencesThe control with specification to hotels and barriers to effective control will also be explained and of course the source of the information.
4Objectives of presentation Explain the transmission of norovirusPresent a real case scenarioOutline the management and control of norovirusPresent the challenges faced in the control of norovirusPresent prevention strategiesThis presentation aims at explaining the epidemiology of the norovirus. A real scenario will be presented and participants will be able to give their views on the management of the case presented in the scenario. The presentation also aims at sharing challenges faced in controlling the virus, prevention strategies and overall management.
5What is norovirus?Norovirus is a single stranded non enveloped RNA virus belonging to the family CaliciviridaeNorovirus, previously called Norwalk-like virus from a gastroenteritis outbreak in Norwalk, Ohio in 1968Norovirus is reported as the single most common cause of gastroenteritis in the western world.CDC (2010). Technical fact sheet on norovirus.What is norovirus? Norovirus is a single stranded non enveloped RNA virus belonging to the family Calicividae. This organism was previously known as the Norwalk-like virus after a gastroenteritis outbreak in Norwalk, Ohio in The virus is reportedly the single most common cause of gastroenteritis in the Western world. The single most common cause of gastroenteritis in the western world; this is cause enough for the epidemiology of the disease to be thoroughly explored and understood so that effective management can be instituted (CDC, 2010).
6What is norovirus (contd) Over 21 million cases of norovirus infections each yearAccounts for more than 50% of total reported food borne illnessesAmong 232 outbreaks reported57% transmitted through food16% transmitted through person to person contact3% waterborne23% undeterminedCDC (2010) reports that there are over 21 million cases of norovirus infections each year which accounts for more than half of the total reported food borne illnesses. Between 1997 and 2000 a total of 232 such outbreaks were reported to CDC of which 57% were transmitted through food, 16% were transmitted through person to person contact, 3% related to contaminated water and in 23% of the cases the source was not determined. So we have named the main ways in which this virus is transmitted. We can now look at the specifics in this transmission pattern.
7Transmission of Norovirus Fecal oral route- Contaminated food- Person to person- Water- Environment to personDroplets from vomitFecal-Oral Route is the primary pathway by which norovirus is transmitted from one individual to the next. At the risk of being a little graphic here is what happens. An infected person passes feces containing the organism. A small amount of the feces (because it only takes a small amount, this may not even be visible) is left on the person’s hands after wiping and still after washing the hands. The individual may work at a hotel or may be a guest at the hotel for example. The contaminated hands touch the toilet door on the way out or the contaminated hands may prepare a cold salad or handle the room keys and some of the norovirus may be deposited on the surfaces touched. An unsuspecting healthy person touches the contaminated surfaces then puts hand in mouth or eats with dirty hand or eats the contaminated food and the virus is now in the stomach of this person. In short the newly infected person has just consumed another person’s feces. We can therefore conclude at thiis early stage oin the presentaion that the hands play a significant role in the transmission, spread and sustainability of norovirus outbreaks.Airborne Inhalation of microscopic droplets to a lesser extent can also be considered a pathway.Person-to-Person contact is an important means of sustaining & spreading an outbreak as you will realize later in the presentationEnvironment-to-Person spread also facilitates the continuity of the of outbreaks.Contaminated fomites are the most likely factor responsible for sustaining a succession of outbreaks
8Signs and Symptoms Diarrhoea Vomiting Fever Abdominal cramps Up to 30% may be asymptomaticDuration – 1-2 daysHow does an individual know when he or she is affected by norovirus or how do the public health official know? The signs and symtoms of this related illness are diarrhoea, vomiting, fever and abdominal cramps. The thing that immediately jumps out at you about these signs and symptoms is that they are the same or similar symptoms that are related to most food borne illnesses. It is also important to note that up to 30% of affected persons may be asymptomatic. So how do we know when the culprit for the illness is this organism?
9Characteristics of Norovirus Seasonal virusHighly infectious ( dose of viral particles)Low virulenceResistant to routine disinfection measuresShedding begins with onset of symptoms and continue for 2 or more weeks after recoveryThis question takes us to the next slide which outlines the main characteristics of norovirus.In the management of norovirus it is essential that the characteristics be known and adequately understood. First of all the virus is seasonal. Documentation of outbreaks have shown where the most active periods are the very cold months and the very hot months. In Jamaica related outbreaks have occurred in the months of December – March. Norovirus is also highly infectious. Earlier in the presentation the fecal-oral pathway was explained and mention was made of the fact that only a very small amount of feces containing the virus was needed to have an health effect. According to CDC (2009), As little as 10 dose of viral particles can result in illness. The organism also has a low virulence and this combined with the shedding in the feces at levels up to 10,000,000 viral particles per gram of feces result in the virus being highly infectious. The resistance to routine disinfection measures is also a key factor in the control as it has implications for the type of chemicals used during cleaning, the method employed and also the frequency of cleaning.When an individual becomes infected shedding begins with the onset of symptoms and continue for 2 or more weeks after recovery. This again will impact on control measures to curtail an outbreak..One projectile vomiting incident can potentially contaminate the environment with 30,000,000 viral particles.Infectious dose of NoV is estimated from viral particles.
10Disease Process Timeline Clinical illnessInfectionIncubation PeriodAsymptomaticSymptomaticEXCRETION OF AGENTThe chart you are looking at outlines the disease process timeline. The days when the excretion of the agent is highest is depicted as days 3 to 4 after exposure or approximately 1 day after the onset of symptoms. The asymptomatic period is also shown as 7 days onwards after exposure.In the absence of laboratory result several factors can be used to identify a norovirus outbreak. These include the fact that it affects all age group, high attack rate and high frequency of vomiting, short duration and incubation period (Lopman et al, 2003).12345678910111213TIME IN DAYSExposureOnset of SymptomsEnd of Symptoms10
11Case StudyIt is one thing to know the theory in disease control but if anyone in this room has ever suffered the pains and discomfort of a foodborne illness or from norovirus in particular then we know that the practical may be more interesting. We are now going to examine a real case study from an outbreak that was experienced by guests, staff and health workers in one parish and attracted national attention.The dates in the report and name of the hotel have been changed to prevent identification of the entity. Any resemblance to the location of any hotel or the similarities in the sequence of events are purely coincidental.
12Case studyFebruary 6, 2005 – Hotel X notifies the health department of the following:- endemic level for GE exceeded- gift shop reported large numbers of guests purchasing Imodium- food history revealed no clear association for person, place and timeOn February 6, 2005 the local health department received a call from the nurse at Hotel X. The nurse was concerned that the endemic level for gastroenteritis had been exceeded. Hotels that offer all inclusive services in Jamaica are required to have a nurses station, named doctors on call and endemic levels for gastroenteritis are calculated based on the number of rooms, number of guests at peek occupancy, history of outbreaks and types of services provided. The endemic level for this particular establishment was 3 guests and 3 staff. Once these figures were exceeded the hotel is mandated to report to the local health department which in turn should respond by initiating an investigation within 24 hours. The nurse also expressed concern that the stock pile of Imodium at the gift shop had been sold out within 3 days. I need to also inform you that when guests report diarrhoea at these hotels it is mandatory that a case history form be completed to include a food history. The nurse had collected the case history and had examined the data for an association between the time or place that the affected persons had ate and also the type of food consumed. She reported that no association was detected.
13Results-preliminary investigation Case definition: Guests or staff who ate at least one meal at Hotel X between February 14 and 21, 2005 and had diarrhea with or without other symptoms14 cases identifiedSigns and symptoms included diarrhea, fever, vomiting, nausea, dehydrationNo significant association between cases and food consumedAttack rate for Block X was the highest (32%)Preliminary investigations were conducted to verify the outbreak. Consequently the disease outbreak investigation team was mobilized and a more comprehensive investigation was conducted. Individuals, whether guests or staff who had eaten at least one meal at Hotel X within the implicated period and had experienced diarrhoea with or without other symptoms were counted as cases. This case definition resulted in the identification of 14 cases. Signs and symptoms included diarrhoea, fever, vomiting, nausea and dehydration. Case history forms were completed to include food history. The data was assessed to determine person, place and time association. The attack rates were calculated and the block with the highest attack rate marked for further investigation.
14Initial action takenComplete assessment done of all food preparation areasReport with recommendation issued to hotelComposite egg samples sent to the labStool specimen sent to the labHistory collected for controlsThe focus was initially on food preparation areas as the initial hypothesis was that the outbreak was due to Salmonella organism. This resulted in a detailed environmental assessment of all food preparation and service areas. The major findings included:Ware washing machine not maintaining adequate temperature for washing and sanitizing of utensilsSeveral colds storage units not maintaining adequate temperaturesA detailed report was prepared and submitted to the property.The hotel was told to collect history for controls in addition to guests.
15Results – overall investigation Case definition expanded35 guests and 14 staff were affectedEpi curve indicated that guests were sick firstIndex case identified with guest room that was previously implicated in an outbreakMany repeat rooms were identifiedInfection spread to the community (1 hospitals and 2 schools)8 persons in the community were affectedDuring the investigation it was noted that the cases were being missed due to the definition so this was extended to include GI cases in general. 35 guests and 14 staff were affected. The epi curve indicated that guests reported sick approximately 1 week before staff commenced reporting. The index case was located on the block with the highest attack rate and was traced to a room that was implicated in an outbreak approximately 2 weeks prior. Many repeat rooms were identified and it was noted that the cleaning protocols were not being adhered to. The rooms were shown to be the primary source of transmission, proven by environmental swabs. The infection was eventually taken to the communitiy, schools and hospital by staff who were sick.
16This slide illustrates the frequency of signs and symptoms experienced by cases
17Overall Action/Outcome Intensified investigationCase definition changed to incorporate gastro intestinal casesGuests quarantinedSick staff sent homeEnvironmental samples sent to labSwimming pools drainedHOTEL ORDERED CLOSEDAs the investigation intensified the case definition was expanded to incorporate persons who had GI symptoms but no diarrhea. Attempts were made to have sick guests confined to their rooms but this proved difficult. Sick staff were sent home and instruucted to remain home for up to 1 week after exhibition of symptoms. Environmental swabs were taken from rooms (door knobs, faucets, etc.) The results were positive for norovirus. The swimming pools were eventually closed as the frequency of fecal accidents in them accelerated. The national authorities were requested to step in and the hotel was ordered closed.
18Challenges for health team No prior history of norovirus hence investigation was not focused on this pathogenDelays in laboratory analyses of the specimen as norovirus testing is only available at the central lab and the testing kits were not readily availableReluctance of hotel guests on holidays to adhere to quarantine proceduresAs you would have imagined the investigation and overall management of the norovirus outbreak was not without challenges. There were challenges on both the side of the health team and also the side of the hotel management and staff. In 2005 the health team had never been exposed to a norovirus outbreak. During outbreaks this pathogen is not normally tested for at the national public health laboratory. Another challenge faced by the team is that the testing kits were not readily available at the lab and had to be sourced overseas. The outbreak was exacerbated by the reluctance of sick guests to adhere to the quarantine procedures outlined by the health department. The hotel management was issued with a written guideline which included procedures for the guests and staff to adhere to in order to curtail the spread. On one occasion a sick guest who was asked to remain in her room had a fecal accident at one of the bars and immediately jumped into the swimming pool. Shortly after other guests were using the pool for swimming and frolicking.
19Challenges for the hotel managerial team Delay in decision by management to:isolate staff who were showing symtomsadhere to cleaning and disinfecting protocols for norovirus in guest rooms and public areasclose swimming pools as requested by the health teamThe hotel managerial team faced challenges in various areas. Their was delay in decision making process to implement recommendations made by the health department. This may have been due to a tousle between economics, pride and politics as evidenced by the outcome of the many meetings held. Staff members who were sick were not kept off the job for the prescribed time, cleaning and disinfecting protocols were not always followed. The issue with accidents in swimming pools was not addressed which increased the risk of transmission through these pools. The health department had actually issued a notice for all swimming pools to be drained.
20Challenges (Cont’d)Close infected rooms were not always closed for 72hrs and were rented as soon as sick guests checked out.Specific teams were not assigned to affected roomsPublic accidents were not addressed according to guidelines.Infected rooms were not always closed for the required 72 hours and general cleaning procedures were not always followed.
21Outcome The following outcomes resulted Mean duration of illness was 2 daysControl measures delayed possibly resulting in spread to the communityTraining of hotel staffPublic education in schoolsOngoing surveillance for norovirusThe mean duration of the illness was 2 days. The control measures were delayed and resulted in spread to the community. All staff members were trained by the health team in norovirus control. Health education was also done at selected schools. There was ongoing surveillance for norovirus.
22ControlWe have looked at the epidemiology of norovirus. We have also looked at a case study which I hope shed some more light on the intricacies of norovirus management. We are now moving into the specifics of norovirus control and management.
23Control norovirus- prevent transmission Good worker hygieneHand washingProhibiting bare hand contact withready-to-eat food itemsRemoving sick food workersEnvironmental cleaning and sanitationManagement attentionCDC (2010). Technical fact sheet on norovirus. Qccessed at:We have examined how norovirus is spread; with the main pathway being fecal-oral. It goes without saying then that the primary control strategy would be to prevent transmission. The following interventions are critical; good worker hygiene, hand washing, prohibiting bare hand contact with ready-to-eat food items, removing food sick food workers from from food areas, environmental cleaning and sanitation and of course management attention. We are now going to talk about each strategy in more details.J. Barker (et al., 2004, J.Hosp.Inf., 58,42-49) used a reverse transcription polymerase chain reaction assay to study the transfer of Norovirus from contaminated faecal material, using fingers and cloths as contact media to other environmental surfaces. Barker found that a when a cloth soaked only in a detergent solution, without a disinfectant, was used to clean-up a Norovirus contaminated area, the cloth actually helped in spreading Norovirus to other environmental surfaces. For this reason, cloths used to clean-up an area contaminated by Norovirus should be disposed, or treated as infectious material, and the initial cleaning should be immediately followed by thorough disinfection of the area.
24Hand washing The first line of defense in the control of norovirus One of the most under-utilized defense strategyHand sanitizers are not substitute for hand washing as alcohol based cleansers are impacted by soil, moisture, is neutralized by protein, and has limited effect on food borne virusesWe are going to incoperate good worker hygiene with hand washing. Throughout the world poor personal hygiene is regarded as the 3rd most common food preparation practice that contributes to food borne diseases and contaminated hands may be the most important means by which enteric bacteria and viruses are transmitted (CDC, 2005). Hand washing is the first line of defense against norovirus and is also the most under-utilized defense strategy. It is important to note that hand sanitizers should not be used as substitute for hand washing as alcohol based cleansers are impacted by soil, moisture, is neutralized by protein and has limited effect on food borne viruses.
25Handwashing Cont’d: Handwash Time: 20 Second Scrub Soap: surfactant effect in removing grease, soil, and debris from the hands.Water Temp: Soap efficacy is tested at ASTM Standards = 40°C +/- 2 degrees ~ (100°F - 107°F)Minimum water temp: 100°FIn a study conducted by Stephens (2008) proper hand washing technique was practiced by less than 40% of the study population. This study was conducted among restaurant workers in the parish of St. Mary, Jamaica. Malhotral, Lal, Prakash, Daga and Kishore (2006) studied the hand hygiene and entero parasite infestation among food handlers working in a medical college in North India. Enteric organisms were isolated from nail clipping specimen of seventy three percent (73%) of study subjects. Hand washing practices were observed to be poor with low use of soap. Findings highlighted the importance of educating food handlers about the importance of maintaining hand hygiene with focus on improving their hand washing practices.Research has shown a minimum second scrub is necessary to remove transient microbes from the hands, and when an antimicrobial soap is used, a minimum of 15 seconds is required. 20 seconds is recommended by CDC. A minimum water temperature of 100 Degree F is also recommended.25
26HANDWASHING: Cont’d Every Stage of hand washing is Important Scrubbing w/ soap = 1 log virus reductionRinsing hands under strong velocity & volume of running water - increased effect in removing transient virusesDrying hands = 1 log virus reductionAll aspects of proper hand washing are important in reducing microbial transients on the hands. However, friction and water have been found to play the most important role. This is why the amount of time spent scrubbing the hands is critical in proper handwashing. It takes more than just the use of soap and running water to remove the transient pathogens that may be present. It is the abrasive action obtained by vigorously rubbing the surfaces being cleaned that loosens the transient microorganisms on the hands. Rinsing the hands under strong strong velocity of water and the drying of hands also reduce microbial load.The additional literature research since the NACMCF meeting indicates that, depending on the microbial contamination level of the hands, handwashing with plain soap and water, as specified in the Code may not be enough to prevent the transmission of viral and protozoan fecal-oral route pathogens via hand contact of ready-to-eat foods2, 3, 4, 12, 16, 34, 35, 39, 58, 61, 62 .Handwashing as specified in the Food Code is also ineffective in preventing transmission of infection when food workers’ hands have a heavy transient bacterial contamination. High levels of microbial contamination of the hands can occur with direct contact with infected bodily fluids12, 18, 19, 21, 22, 34, 35, 38, 54, 72, 74.The handwashing technique as recommended in the Food Code will only result in a 2-log (one hundred fold) reduction in microorganisms on the hands. This 2-log reduction is insufficient with individuals infected with enteric viruses, which are shed in the feces as high as 1010 viron particles per gram of feces, and enteric protozoa which are shed in the feces as high as 108 oocysts per gram of feces.26
27No Bare Hand ContactReview food service practices to ensure no-bare hand contact with ready-to-eat foods including fruits, breads, and garnishesUse gloves, tongs, tissue, utensilsRemember that employees can shed bacteria and viruses even when not symptomaticWith the level of concern and the evidence from studies done it goes without saying that bare hand contact with ready-to-eat foods should be discouraged. This is even more critical during a norovirus outbreak. It is also of equal importance that the gloves, tongs, or utensils used are clean and free of harmful microorganisms.
28Remove sick workers Based on 4 Levels of Risk Based on infective periodBalances employee’s needs with risk to the publicProvides guidance on safely allowing infected employees to return to dutiesFour levels of illness or potential illness have been identified with the first level being the highest potential risk to public health and the fourth level being the lowest. The first level relates to employees who have specific symptoms (e.g. vomiting, diarrhea, jaundice) while in the workplace. These symptoms are known to be associated commonly with the agents most likely to be transmitted from infected food workers through contamination of food. The second level relates to employees who have been diagnosed with the specific agents that are of concern, but who are not exhibiting symptoms of disease because their symptoms have resolved. The third level relates to employees who are diagnosed with the specific agents, but never developed any gastrointestinal symptoms to begin with. The fourth level relates to those individuals who are clinically well but who may have been exposed to a listed pathogen and are within the normal incubation period of disease.Guidelines must be given pertaining to the time employees return to work. This period will vary based on the pathogen. It is critical to note that norovirus can still be shed for several days after symptoms disappear. In the case study that was presented the health department had stipulated a 1 week period away from work after symptoms disappeared.28
29Environmental cleaning & disinfecting Reducing airborne transmissionTreat contaminated material as infectious wasteCleaning Staff should use barriers, such as disposable face masks, gloves, shoes covering and aprons.Dispose of materials used to clean-up vomiting incident, and thoroughly disinfect the area (eg. Mop heads and wipe cloths)It is apparent from earlier in the presentation that environment to person contact is also a critical way in which norovirus is transmitted. It is therefore very important that cleaning and disinfection protocols for this particular virus are adhered to. Based on the nature of norovirus outbreaks, the conditions for spread and the characteristics of the pathogen routine cleaners and cleaning procedures are not effective and as such prescribed procedures for reducing airborne transmission and treat contaminated material as infectious waste. In implementing the plan management must exercise caution to ensure that cleaning crew and material do not serve as vehicle for continuous spread. One recommendation is that a specific cleaning crew be used to clean affected areas. Barriers such as disposable masks, gloves, shoes covering and overcoats. Soiled linen and other contaminated material such as wipe cloths and mop heads should be disposed of in a manner that will not pose a further problem.
30Norovirus disinfection Norovirus survives 0°C to 60°CAcceptable food heat treatment– Ultra High Pasteurization56°C for 60 min., 70°C for 5 min., or 100°C for 1 min. for complete inactivation of the virus or70°C for 3 min. for 6.5 log10 reductionCruise Ship Industry uses chemical disinfection of carpets/ followed by steam cleaning: 70°C for 5 minutesIn cleaning and disinfecting we must remember that norovirus survives 0°C to 60°C. Ultra high pasteurization is adequate to destroy the virus. The cruise ship industry employ chemical disinfection of carpets followed by steam cleaning at 70°C for 5 minutes.
31Other disinfectants Glutaraldehyde 0.5% Iodine 0.8% Hypochlorite—Household bleach—1000 ppmOther disinfectants include Glutaraldehyde 0.5%, iodine 0.8%, Household bleach at 1000 ppm.
32Management supervision Review guidelinesEnsure adherence to cleaning protocolsEnsure continued training of staffEnsure adherence to quarantine guidelinesManagement’s commitment is key in reducing the spread of norovirus on cruise ships, hotels, schools, nursing homes and any other institutions. Management needs to be familiar with the relevant guidelines in norovirus control.
33Barriers to effective control Economic cost to the establishmentSalary loss to staffDifficulty in isolating persons because of their movements in and out of the institutionBarriers to effective control include economic cost to the establishment, reputation of the establishment, salary loss to staff and as noted earlier the difficulty faced with isolating staff.
34Conclusion Norovirus causes significant morbidity and economic loss. Attention to the different protocols for control can reduce the spreadEarly recognition and intervention will limit spreadA team approach is necessary for controlIn concluding, let us look at what we have learned. We know that norovirus is responsible for a significant number of foodborne illnesses reported each year and causes morbidity and economic loss. We also know that when attention is paid to the different protocols for control the spread can be reduced and early recognition and implementation of intervention strategies will limit the spread of the virus. It is also critical to note that a team approach is necessary for rapid and effective control.
35ReferencesCDC. (2010). Technical fact sheet on norovirus. Accessed 20/10/2010 at:Kaplan JE, Feldman R, Campbell DS, Lookabaugh C, Gary GW. The frequency of a Norwalk-like pattern of illness in outbreaks of acute gastroenteritis. Am J Public Health 1982;72:1329–32.Lillquist D., McCabe M.L., Church K.H., (2005). “A comparison of traditional hand washing training with active hand washing training in the food handler industry”. Journal of Environmental Health 67(6),The following references were utilized to prepare this presentation.
36References Cont’dLopman BA, Adak GK, Reacher MH, Brown DWG. Two epidemiologic patterns of Norovirus outbreaks: surveillance in England and Wales, Emerg Infect (2003). Available from: URL:Ministry of Health (2008). Foodborne outbreak investigations – the norovirus experience. MOHStephens, R. (2007). Hand washing compliance in restaurants, St. Mary, Jamaica. (Unpublished)This slide contains references for further reading.
37Further readingCDC. Norovirus Outbreaks on Three College Campuses --- California, Michigan, and Wisconsin, MMR Weekly. Access at:
38THANK YOU Questions?Thank you for your attention and I trust that when you enter the working world you will benefit from the lessons learned in this presentation. Have a great day.
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