CONTROL OF NOROVIRUSCONTROL OF NOROVIRUS

Prepared by Erva-Jean Stevens (PhD Candidate)

Walden UniversityEnvironmental Health

October, 2010

Prepared by Erva-Jean Stevens (PhD Candidate)

Walden UniversityEnvironmental Health

October, 2010

OutlineOutline

• Objectives• What is Norovirus• Transmission of norovirus• Signs and symptoms• Characteristics of norovirus• Case study - presentation of cases - preliminary investigations

• Objectives• What is Norovirus• Transmission of norovirus• Signs and symptoms• Characteristics of norovirus• Case study - presentation of cases - preliminary investigations

Outline cont’dOutline cont’d

-laboratory findings - management and control - challenges - outcome• Control – prevention of transmission• Barriers to effective control• Control • References

-laboratory findings - management and control - challenges - outcome• Control – prevention of transmission• Barriers to effective control• Control • References

Objectives of presentationObjectives of presentation

• Explain the transmission of norovirus

• Present a real case scenario

• Outline the management and control of norovirus

• Present the challenges faced in the control of norovirus

• Present prevention strategies

• Explain the transmission of norovirus

• Present a real case scenario

• Outline the management and control of norovirus

• Present the challenges faced in the control of norovirus

• Present prevention strategies

What is norovirus?What is norovirus?

• Norovirus is a single stranded non enveloped RNA virus belonging to the family Caliciviridae

• Norovirus, previously called Norwalk-like virus from a gastroenteritis outbreak in Norwalk, Ohio in 1968

• Norovirus is reported as the single most common cause of gastroenteritis in the western world.

CDC (2010). Technical fact sheet on norovirus. http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

• Norovirus is a single stranded non enveloped RNA virus belonging to the family Caliciviridae

• Norovirus, previously called Norwalk-like virus from a gastroenteritis outbreak in Norwalk, Ohio in 1968

• Norovirus is reported as the single most common cause of gastroenteritis in the western world.

CDC (2010). Technical fact sheet on norovirus. http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

What is norovirus (contd)What is norovirus (contd)

• Over 21 million cases of norovirus infections each year

• Accounts for more than 50% of total reported food borne illnesses

• Among 232 outbreaks reported 1997-2000- 57% transmitted through food- 16% transmitted through person to person contact- 3% waterborne- 23% undetermined

• Over 21 million cases of norovirus infections each year

• Accounts for more than 50% of total reported food borne illnesses

• Among 232 outbreaks reported 1997-2000- 57% transmitted through food- 16% transmitted through person to person contact- 3% waterborne- 23% undetermined

Transmission of NorovirusTransmission of Norovirus

• Fecal oral route

- Contaminated food

- Person to person

- Water

- Environment to person

• Droplets from vomit

• Fecal oral route

- Contaminated food

- Person to person

- Water

- Environment to person

• Droplets from vomit

Signs and SymptomsSigns and Symptoms

• Diarrhoea• Vomiting• Fever• Abdominal cramps• Up to 30% may be asymptomatic

• Duration – 1-2 days

• Diarrhoea• Vomiting• Fever• Abdominal cramps• Up to 30% may be asymptomatic

• Duration – 1-2 days

Characteristics of NorovirusCharacteristics of Norovirus

• Seasonal virus

• Highly infectious (10-100 dose of viral particles)

• Low virulence

• Resistant to routine disinfection measures

• Shedding begins with onset of symptoms and continue for 2 or more weeks after recovery

• Seasonal virus

• Highly infectious (10-100 dose of viral particles)

• Low virulence

• Resistant to routine disinfection measures

• Shedding begins with onset of symptoms and continue for 2 or more weeks after recovery

0 1 2 3 4 5 6 7 8 9 10 11 12 13TIME IN DAYSE

XC

RE

TIO

N O

F A

GE

NT

Clinical illness

Infection

Disease Process Timeline

Incubation Period

AsymptomaticSymptomatic

Exposure Onset of Symptoms End of Symptoms

Case StudyCase Study

Case studyCase study

• February 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 time

• February 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 time

Results-preliminary investigationResults-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 symptoms

• 14 cases identified• Signs and symptoms included diarrhea, fever,

vomiting, nausea, dehydration• No significant association between cases and

food consumed• Attack rate for Block X was the highest (32%)

• 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 symptoms

• 14 cases identified• Signs and symptoms included diarrhea, fever,

vomiting, nausea, dehydration• No significant association between cases and

food consumed• Attack rate for Block X was the highest (32%)

Initial action takenInitial action taken

• Complete assessment done of all food preparation areas

• Report with recommendation issued to hotel

• Composite egg samples sent to the lab

• Stool specimen sent to the lab

• History collected for controls

• Complete assessment done of all food preparation areas

• Report with recommendation issued to hotel

• Composite egg samples sent to the lab

• Stool specimen sent to the lab

• History collected for controls

Results – overall investigationResults – overall investigation• Case definition expanded

• 35 guests and 14 staff were affected

• Epi curve indicated that guests were sick first

• Index case identified with guest room that was previously implicated in an outbreak

• Many repeat rooms were identified

• Infection spread to the community (1 hospitals and 2 schools)

• 8 persons in the community were affected

• Case definition expanded

• 35 guests and 14 staff were affected

• Epi curve indicated that guests were sick first

• Index case identified with guest room that was previously implicated in an outbreak

• Many repeat rooms were identified

• Infection spread to the community (1 hospitals and 2 schools)

• 8 persons in the community were affected

Signs and symptoms experienced by cases

05

10152025303540

signs and symptoms

# ca

ses

cases

Overall Action/OutcomeOverall Action/Outcome

• Intensified investigation

• Case definition changed to incorporate gastro intestinal cases

• Guests quarantined

• Sick staff sent home

• Environmental samples sent to lab

• Swimming pools drained

• HOTEL ORDERED CLOSED

• Intensified investigation

• Case definition changed to incorporate gastro intestinal cases

• Guests quarantined

• Sick staff sent home

• Environmental samples sent to lab

• Swimming pools drained

• HOTEL ORDERED CLOSED

Challenges for health teamChallenges for health team

• No prior history of norovirus hence investigation was not focused on this pathogen

• Delays in laboratory analyses of the specimen as norovirus testing is only available at the central lab and the testing kits were not readily available

• Reluctance of hotel guests on holidays to adhere to quarantine procedures

• No prior history of norovirus hence investigation was not focused on this pathogen

• Delays in laboratory analyses of the specimen as norovirus testing is only available at the central lab and the testing kits were not readily available

• Reluctance of hotel guests on holidays to adhere to quarantine procedures

Challenges for the hotel managerial team

Challenges for the hotel managerial team

• Delay in decision by management to:

- isolate staff who were showing symtoms

- adhere to cleaning and disinfecting protocols for norovirus in guest rooms and public areas

- close swimming pools as requested by the health team

• Delay in decision by management to:

- isolate staff who were showing symtoms

- adhere to cleaning and disinfecting protocols for norovirus in guest rooms and public areas

- close swimming pools as requested by the health team

Challenges (Cont’d)Challenges (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 rooms

• Public accidents were not addressed according to guidelines.

• 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 rooms

• Public accidents were not addressed according to guidelines.

OutcomeOutcome

• The following outcomes resulted

- Mean duration of illness was 2 days

- Control measures delayed possibly resulting in spread to the community

- Training of hotel staff

- Public education in schools

- Ongoing surveillance for norovirus

• The following outcomes resulted

- Mean duration of illness was 2 days

- Control measures delayed possibly resulting in spread to the community

- Training of hotel staff

- Public education in schools

- Ongoing surveillance for norovirus

ControlControl

Control norovirus- prevent transmission

Control norovirus- prevent transmission

• Good worker hygiene• Hand washing • Prohibiting bare hand contact with ready-to-eat food items • Removing sick food workers• Environmental cleaning and sanitation• Management attention

CDC (2010). Technical fact sheet on norovirus. Qccessed at:http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

• Good worker hygiene• Hand washing • Prohibiting bare hand contact with ready-to-eat food items • Removing sick food workers• Environmental cleaning and sanitation• Management attention

CDC (2010). Technical fact sheet on norovirus. Qccessed at:http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

Hand washingHand washing

• The first line of defense in the control of norovirus

• One of the most under-utilized defense strategy

• Hand 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 viruses

• The first line of defense in the control of norovirus

• One of the most under-utilized defense strategy

• Hand 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 viruses

Handwashing Cont’d:Handwashing 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°F

• 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°F

HANDWASHING: Cont’d

HANDWASHING: Cont’d

• Every Stage of hand washing is Important

• Scrubbing w/ soap = 1 log virus reduction

• Rinsing hands under strong velocity & volume of running water - increased effect in removing transient viruses

• Drying hands = 1 log virus reduction

• Every Stage of hand washing is Important

• Scrubbing w/ soap = 1 log virus reduction

• Rinsing hands under strong velocity & volume of running water - increased effect in removing transient viruses

• Drying hands = 1 log virus reduction

No Bare Hand Contact No Bare Hand Contact

• Review food service practices to ensure no-bare hand contact with ready-to-eat foods including fruits, breads, and garnishes

• Use gloves, tongs, tissue, utensils

• Remember that employees can shed bacteria and viruses even when not symptomatic

• Review food service practices to ensure no-bare hand contact with ready-to-eat foods including fruits, breads, and garnishes

• Use gloves, tongs, tissue, utensils

• Remember that employees can shed bacteria and viruses even when not symptomatic

Remove sick workersRemove sick workers

• Based on 4 Levels of Risk

• Based on infective period

• Balances employee’s needs with risk to the public

• Provides guidance on safely allowing infected employees to return to duties

• Based on 4 Levels of Risk

• Based on infective period

• Balances employee’s needs with risk to the public

• Provides guidance on safely allowing infected employees to return to duties

Environmental cleaning & disinfecting

Environmental cleaning & disinfecting

• Reducing airborne transmission• Treat contaminated material as infectious

waste• Cleaning 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)

• Reducing airborne transmission• Treat contaminated material as infectious

waste• Cleaning 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)

Norovirus disinfectionNorovirus disinfection

• Norovirus survives 0°C to 60°C

• Acceptable food heat treatment– Ultra High Pasteurization– 56°C for 60 min., 70°C for 5 min., or 100°C for

1 min. for complete inactivation of the virus or – 70°C for 3 min. for 6.5 log10 reduction

• Cruise Ship Industry uses chemical disinfection of carpets/ followed by steam cleaning: 70°C for 5 minutes

• Norovirus survives 0°C to 60°C

• Acceptable food heat treatment– Ultra High Pasteurization– 56°C for 60 min., 70°C for 5 min., or 100°C for

1 min. for complete inactivation of the virus or – 70°C for 3 min. for 6.5 log10 reduction

• Cruise Ship Industry uses chemical disinfection of carpets/ followed by steam cleaning: 70°C for 5 minutes

Other disinfectantsOther disinfectants

• Glutaraldehyde 0.5% Iodine 0.8%

• Hypochlorite—Household bleach—1000 ppm

• Glutaraldehyde 0.5% Iodine 0.8%

• Hypochlorite—Household bleach—1000 ppm

Management supervisionManagement supervision

• Review guidelines

• Ensure adherence to cleaning protocols

• Ensure continued training of staff

• Ensure adherence to quarantine guidelines

• Review guidelines

• Ensure adherence to cleaning protocols

• Ensure continued training of staff

• Ensure adherence to quarantine guidelines

Barriers to effective controlBarriers to effective control

• Economic cost to the establishment

• Salary loss to staff

• Difficulty in isolating persons because of their movements in and out of the institution

• Economic cost to the establishment

• Salary loss to staff

• Difficulty in isolating persons because of their movements in and out of the institution

ConclusionConclusion

• Norovirus causes significant morbidity and economic loss.

• Attention to the different protocols for control can reduce the spread

• Early recognition and intervention will limit spread

• A team approach is necessary for control

• Norovirus causes significant morbidity and economic loss.

• Attention to the different protocols for control can reduce the spread

• Early recognition and intervention will limit spread

• A team approach is necessary for control

ReferencesReferences

• CDC. (2010). Technical fact sheet on norovirus. Accessed 20/10/2010 at: http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

• 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), 13-16.

• CDC. (2010). Technical fact sheet on norovirus. Accessed 20/10/2010 at: http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-factsheet.htm

• 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), 13-16.

References Cont’dReferences Cont’d

• Lopman BA, Adak GK, Reacher MH, Brown DWG. Two epidemiologic patterns of Norovirus outbreaks: surveillance in England and Wales, 1992-2000. Emerg Infect (2003). Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no1/020175.htm

• Ministry of Health (2008). Foodborne outbreak investigations – the norovirus experience. MOH

• Stephens, R. (2007). Hand washing compliance in restaurants, St. Mary, Jamaica. (Unpublished)

• Lopman BA, Adak GK, Reacher MH, Brown DWG. Two epidemiologic patterns of Norovirus outbreaks: surveillance in England and Wales, 1992-2000. Emerg Infect (2003). Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no1/020175.htm

• Ministry of Health (2008). Foodborne outbreak investigations – the norovirus experience. MOH

• Stephens, R. (2007). Hand washing compliance in restaurants, St. Mary, Jamaica. (Unpublished)

Further readingFurther reading

• CDC. Norovirus Outbreaks on Three College Campuses --- California, Michigan, and Wisconsin, 2008. MMR Weekly. Access at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5839a2.htm

• CDC. Norovirus Outbreaks on Three College Campuses --- California, Michigan, and Wisconsin, 2008. MMR Weekly. Access at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5839a2.htm

THANK YOU

Questions?

THANK YOU

Questions?

04/21/23 Free Template from www.brainybetty.com

39