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Norovirus: The Modern Scourge of Food and Family Ewen C. D. Todd Ewen Todd Consulting Okemos, Michigan Discussant.

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Presentation on theme: "Norovirus: The Modern Scourge of Food and Family Ewen C. D. Todd Ewen Todd Consulting Okemos, Michigan Discussant."— Presentation transcript:

1 Norovirus: The Modern Scourge of Food and Family Ewen C. D. Todd Ewen Todd Consulting Okemos, Michigan Discussant

2 CDC and FDA Information on NoV US: 20 million cases of gastrointestinal illness are caused by noroviruses (NoV) each year US: 5.5 million NoV cases (3-8 million range) foodborne Widespread throughout the world but not reported often in developing countries Thorough hand-washing with hot water and soap and immediate sanitizing of contaminated surfaces and clothing is recommended to prevent the spread of the virus If symptoms last longer than 48 hours, people should seek medical care; deaths rare, mainly in the elderly Foodborne outbreaks, typically much handled RTE foods: various salads, sandwiches, bakery products, cake icing, raspberries, oysters. FDA Food Code does not permit alcohol spray or gel use without handwashing

3 Outbreaks Follow Outbreaks Madison, WI, with five food-related outbreaks since last November – church social event; pub; high school; conference center; art show – Health Department: likely by food workers or people attending the various events North Carolina: Longterm care facility in Carteret County, >20 patients ill and several hospitalized over the last few days with symptoms of norovirus following a similar outbreak in Pitt County last week New Jersey: 40 Rider University students hospitalized connected to an ongoing Princeton outbreak – Poor hand hygiene likely a major factor in spread Not uncommon for cruise ships to have 2-3 repeated cruises with infections even after clean up, e.g., Celebrity Mercury on 3 consecutive cruises in 2010

4 Poor Hand Hygiene a Major Factor in NoV Spread Although 83.0% of students at University of Guelph indicated that they practiced correct hand hygiene during a NoV outbreak, but observed compliance with prescribed hand hygiene recommendations occurred only 17.4% of the time.

5 Vomitus a Key Factor in NoV Spread San Francisco: 300 staff and students at a high school ill from vomitus on a door handle – "A student vomited on central doors, on the rods that open these big doors. Then the bell rang and a lot of students went through that door.“ – a bleach-based solution was used to clean up Washington: 229 cheerleading, dance and drill team were sickened at a state competition – facilities were sanitized ahead of the event but janitors had to clean up vomit in a restroom and on an adjacent walkway which would be enough to start the transmission process Vomitus can also be aerosolized to travel some distance

6 Environmental Contamination Bacteria and viruses are transmitted by droplets generated when talking, sneezing, coughing or vomiting Shaking a contaminated piece of cloth or vacuuming a soiled carpet may disturb airborne particles that have settled there and be ingested Aerosol transmission of norovirus has been well documented – Patrons and staff in food service settings have become ill when a “public vomiting” event has occurred in another area of the establishment

7 Guidelines for Environmental Cleaning and Disinfection of Norovirus Guidelines_for_environmental_cleaning_1236234_7(1).pdf Wear gloves, mask; wipe up vomitus, soak with bleach, bag and discard Do not vacuum Wash hands carefully with soap and water, especially after using the toilet and changing diapers and always before eating or preparing food Alcohol-based hand sanitizers (containing at least 62% ethanol) may be a helpful addition to hand washing, but they are not a substitute for washing with soap and water

8 NoV Outbreaks on Cruise Ships in 2012 Princess Cruises Ruby Princess Crown Princess 02/04- 02/09 Norovirus Celebrity CruisesCelebrity Silhouette01/29-02/10Unknown Celebrity CruisesCelebrity Constellation01/28-02/11Unknown Princess CruisesCrown Princess01/28-02/04Norovirus P & O CruisesAurora01/04-01/26

9 Five Cruise Ships in Nassau, January 29, 2012

10 Washy-washy - Avoiding NoV on Cruise Ships (not)

11 The Role of Food and Food Workers Indiana: >100 infected with norovirus January had eaten at a local Subway franchise in 2012 – "A customer could have left it on a door knob. Or an employee could have caused it by poor hand washing.“ Six norovirus outbreaks (1,143 cases) in institutions or commercial catering settings, June to Sept. 2005 in Denmark, linked to frozen raspberries imported from Poland Sick cook at a Lansing, Michigan, restaurant sickened 500 in a weekend in 2006; two other NoV outbreaks occurred in the same month

12 The Role of Food and Food Workers Cake frosting contaminated with norovirus caused 3,000 cases in 1982 in Minnesota, over 1,000 cases in Georgia in 2000, and 2,700 cases in 2002 in Massachusetts; these outbreaks resulted from infected workers who contaminated icing during preparation through hand contact with fecal matter – Long nails or artificial nails can trap fecal matter and are not easy to clean Asymptomatic infections are common and may play an important role in outbreaks caused by food workers Also, infected persons can continue to excrete the virus for weeks after they have recovered WHO study: alcohol-based product may work against NoV: 80% (vol/vol) ethanol, 1.45% (vol/vol) glycerol, and 0.125% (vol/vol) hydrogen peroxide

13 Causative Pathogens Involving Food Workers (Greig et al., 2007; Todd et al., 2008-2010) 1927 to first quarter of 2006: 816 outbreak reports with 80,682 cases Pathogens: – norovirus/Norwalk-like virus (probable norovirus) (338) – Salmonella enterica (151) – hepatitis A virus (84) – Staphylococcus aureus (53) – Shigella spp (33) – Streptococcus pyogenes Group A (17) – Parasites Cyclospora, Giardia, and Cryptosporidium (23)

14 Infections from Soiled Laundry Scots husband and wife, both 83, died only days apart in 2010 – Mrs. McEwen fell ill with norovirus while a patient in Queen Margaret Hospital, Dunfermline, and her husband became infected after taking his wife's laundry home to wash, unaware of potentially fatal risk from germs clinging to the clothing In such hospitals soiled garments which belong to patients are placed in special sealed bags to give to relatives to wash at home along with handling instructions – Professor Hugh Pennington in his call for a review of hygiene practices states: ''We are getting to grips with MRSA and C. diff but norovirus is a problem we are no getting to grips with yet,'' he said – “We should not expect relatives to take home the washing of patients any longer; norovirus is a serious matter in hospitals and is more infectious that either MRSA or C. diff.''

15 Laundering Effect on Viruses Gerba and Kennedy (2007) examined the effectiveness of home laundering of cotton cloths to eliminate enteric viruses that can have peak concentrations in feces of 10 10 -10 11 particles/g – Washing cotton with detergent alone led to virus reductions of only 92 to 99% – Viruses are readily transferred from contaminated cloths to uncontaminated clothes The most important factors for the reduction of virus in laundry were passage through the drying cycle and the addition of sodium hypochlorite – Hypochlorite reduced the number of infectious virus particles on the cotton after washing and drying by at least 99.99%

16 Laundering of Clothing Laundering process relies on disinfection through washing, physical removal, dilution, and the effects of soap and/or sanitizer, and temperatures achieved during washing, rinsing and drying However, aerosols from contaminated clothing may occur if the agitation speed in laundry operations is set too high Hot water and dryer temperatures increase the overall sanitary quality of laundered fabrics Detergents and alkaline compounds are best added at the second-last step in the wash cycle before the final rinse Washing soiled fabrics routinely produced fabric containing less than 1 cfu/cm 2 (6.5 cfu/sq. in)

17 California Department of Public Health Guidelines for Norovirus Put linens soiled with vomit or fecal matter in a plastic bag before sending them to the laundry Encourage staff working in the laundry to wear gloves, a mask, and a disposable gown (or to change their clothes) when physical contact with soiled linens is necessary Wash soiled clothing in hot water using any commercial laundry detergent and disinfectant Dry clothes in a dryer; use chlorine-containing (hypochlorite) solutions in a 1:100 (500 ppm) to 1:10 (5,000 ppm) dilution Clean carpets and soft furnishings with hot water and detergent, or steam clean; do not dry vacuum

18 QRA NoV Restaurant (Mokhtari and Jaykus, 2009) Solid lines represent transmission (change of contamination status from non- contaminated to contaminated), while dashed lines represent influences on these transmissions. τij represents transfer rate between sources i and j, where i and j are selected among food products (F), gloves (G), hands (H), and food contact surfaces (S).

19 QRA NoV Restaurant (Mokhtari and Jaykus, 2009) Illustrative example of random assignment of contact events to food preparation events. Contact events include: (a) between hands (gloves) and food products; (b) between hands (gloves) and surface; and (c) between surface and food products. Numbers of contacts are na, nb, and nc for the contact events a, b, and c, respectively.

20 QRA NoV Restaurant (Mokhtari and Jaykus, 2009) Assumed that each food preparation event requires three minutes. Moreover, each employee may prepare at least one and up to 100 servings of food during a working shift (e.g., an eight hour period). The starting time for each food preparation event was randomly selected within this period. The frequency and sequence of contacts for each of the events a, b, or c were randomly assigned to food preparation events (Figure). For example, if four contacts between hands (gloves) and food products (a), three contacts between hands (gloves) and surfaces (b), and two contacts between food products and surfaces (c)were assumed to happen in one food preparation event, a random order of {a, c, b, a, b, b, a, c, a} for the sequence in which these events might happen was assigned to one food preparation event.

21 Questions That May Impact Management Decisions Is the reason for sequential outbreaks because NoV infections are widespread in the community, or clean up of facilities (e.g., ship, restaurant) is ineffective, or there is a remaining human source (e.g., ship crew, food workers) to reinfect patrons? Are the any breakthroughs for alcohol based compounds for destroying NoV and other non-enveloped viruses? NoVs are a bigger problem for the food industry than in the health care industry where alcohol-based compounds are exclusively used Are there uniform standards and policies for disinfecting soiled laundry and carpets, upholstery, equipment that might contain NoVs? How do improve handwashing compliance and efficiency in food and health care facilities? Can we get sick leave policies to be implemented in foodservice? What more data do we need to carry out a quantitative or qualitative risk assessments?

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