Welcome Address Clodagh Fitzgerald Chair, NHP 20 th February 2013
Norovirus and the Leisure Industry Dr Paul McKeown Health Protection Surveillance Centre 2
Outline • Background • The Virus • Prevention & Control 3
4
Prejudices & Preconceptions • Not worthy of attention • Minor illness • How many people has it killed this year? • Difficult to diagnose • Clean it up quickly and things will be fine • Sawdust and Jeyes Fluid = All Things to All Men • Vomit isn't infectious not like diarrhoea • “Actually I’m trying to run a hospital/hotel here, in case you hadn't noticed…”
Background and Discovery • 1929 Dr. John Zahorsky – “winter vomiting disease” • Bacterial gastroenteritis agents readily identified – bacteria are larger – can be readily filtered • Before viruses could be identified or visualised – huge burden of “viral gastroenteritis” • Noroviruses cannot be cultured (grown) made identification even harder • Norwalk OH – October 1968 – Elementary school – 50% (116/232) pupils and staff – 32% secondary attack rate • “Norwalk” virus 6
Virology - Caliciviridae RNA virus – genetically flexible 38nm diameter GGII Norovirus GGI Sapovirus 7
Microbial Dimensions 8
0.1mm 9
0.025mm 10
A Salmonella Bacterium 11
200 nm* Each Salmonella bacterium is 1000nm or 1/1000mm long *1 millimetre = 1 000 000 nanometers 12
Each Norovirus is about 35nm in diameter 10,000 Noroviruses would stretch across the waist of the dot on the letter “i” of standard news print 13
More Meaningful Context… The tip of the Dublin Spire is 6 inches in across – Were the Dublin Spire a hypodermic needle, a Norovirus particle would, relatively speaking, be the same size as a POINT of a pin 14
Background • Leading causes of gastroenteritis • Causes particular problems where people congregate (hospitals, nursing and residential homes, childcare facilities, schools, hotels, cruise ships and places of employment) • Rapid spread both faeces (bowel motions) and vomitus • Greater congregation in winter → ↑ proximity → ↑ dissemination → ↑ risk of outbreaks • Such outbreaks massive disruption to → : – disruption to care – disruption to business continuity, – substantial economic loss, and, – mortality in vulnerable patient populations (occasionally). 15
Molecular Identification • 1995-6: first identification of global epidemic – GII.4 strain • The latest is the Sydney strain • Shift and drift • Readily genetically mutable, → short term/partial immunity • Able to reinfect in a very short time period (<3/12) • Certain individuals with a particular genetic profile have innate resistance (probably accounts for apparently discriminatory nature of human infection during outbreaks) NVRL 16
Epidemiology • 50% of all global GE outbreaks • ≈ 23 million cases pa in US • Antibodies by age 3-4; >50% prevalence by 50 years • 20% adult GP attendances for acute GE have evidence of NoV • 5-10% of children with acute GE have NoV • >10 6 particles/g or ml of vomitus or faeces • Tiny inoculum (1-10 particles) 17
How common is Norovirus? • Seasonal variations – low in summer, higher in winter • Hard to accurately gauge • One percent of the population affected during low activity years • This rises to 3-5% during upsurge seasons • Typical NoV season lasts ∼ 14-20 weeks so: – Low activity season (1%) ∼ 2,000 cases/wk (or 40,000 per season) – Upsurge season (3-5%) ∼ 6,600 and 11,000 cases/wk (132,000-220,000) • Recent work in the Netherlands indicates (using their estimates) that Ireland could have 170,000 cases per year (120,000-240,000) 18
Norovirus Seasonality - Netherlands 120 II4 Aantal gemelde outbreaks 100 non II4 80 60 40 20 0 0 1 2 3 4 5 6 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 Source : Koopmans M, van Pelt W 19
Norovirus Seasonality – Ireland* *Notifications (Blue) Outbreaks (Red) 20
Clinical Features • Incubation period*: 24-48 hours (range 18-72 hours) • Onset: Gradual or abrupt – often “ public vomiting ” – aerosol formation • Gastrointestinal symptoms: – Nausea ∼ 80% – Vomiting ∼ 70% – Abdominal cramps ∼ 30% – Non-bloody diarrhoea (4-8 stools per day) ∼ 70% – May be Vomiting and/or diarrhoea • Systemic symptoms: – Muscle aches ∼ 25% – Headache ∼ 25% – Malaise (generally feeling seedy) – Fever in ∼ 40% (38.0-39 0 C ) • Duration: 12-72 hours *The period between taking the virus into the body and developing symptoms 21
Diagnosis • Outbreak criteria (Kaplan) – very characteristic picture – Bacterial infection excluded – Vomiting >50% of cases – Mean incubation period: 24-48 hours – Mean duration of illness: 12-60 hours • Laboratory – Electron microscopy (SRSV) – PCR - polymerase chain reaction – amplifies DNA (and RNA) – ELISA – uses antibodies to detect a pathogen 22
Surveillance • Departments of Public Health → HPSC • Notifications and outbreaks reported • Not all cases reported • Sufficient to gauge trends and determine overall level of activity • Alerts are sent out when levels high 23
National Reporting Week 5 (Jan 28 – Feb 3) 24
Number of Norovirus/suspected norovirus outbreaks and resultant numbers ill for Weeks 40 - 51 2012 Number Number Number Outbreak location outbreaks Number ill hospitalised deceased Comm. Hosp/ Long-stay unit 28 656 20 1 Residential institution 21 318 6 0 Hospital 20 533 284 0 Hotel 4 106 0 0 Childcare Setting 1 25 0 0 Restaurant / Cafe 1 4 1 0 School 1 17 0 0 Other 1 19 2 Total 77 1678 313 1 25
So, why is Norovirus so easily spread? • • Hardy Asymptomatic infection common • • Temperature stable ( survives Survives weeks in the >60 0 C – 25% survive >75 0 C) environment • • Small infectious dose Multiple transmission routes (persons-to-person, food, water, • Genetically mutable aerosol) • Limited immunity • Resistant to most disinfectants • High 2 0 infection rate (>40%) (requires household bleach at a • Prolonged shedding (for several concentration of 1:1000) days) • Large human reservoir with high numbers of susceptibles 26
Where are noroviruses found during Hospital outbreaks? Norwich 2011 • Soap dispensers • Patients lockers • Computer keyboards In other words – • Computer mice those areas that are • Telephones most frequently • Door handles touched by hands • Light switches • Hand/grab rails 27
Guidance • HPSC has Norovirus resources on its website • Available at http://www.hpsc.ie/hpsc/A-Z/Gastroenteric/Norovirus/Publications/ • Key document - Guidance on the Management of Outbreaks of Noroviral Infection in Tourist and Leisure Industry Settings • Available at http://www.hpsc.ie/hpsc/A-Z/Gastroenteric/Norovirus/Publications/File,2 28
General Control Measures • Clean up vomit - widely → aerosolisation • Decontaminate • Cleaning toilet areas • Washing hands • Exclude for 48H • Food handlers should NEVER clean up soiling 29
Control in Hotel Setting • Guidance on the Management of Outbreaks of Noroviral Infection in Tourist and Leisure Industry Settings at www.hpsc.ie • NoV cannot be prevented - but it can be controlled • Duty-of-care issues • Hotels are vulnerable to norovirus outbreaks – Vulnerable individuals (e.g. elderly, young children) – Communal food sources – Communal areas – Mobility of staff – Economic consequences • Key is Preparedness 30
Preparedness in Hotel Setting Development of Policy and Protocols • Cleaning and • Isolation of sick guests decontamination • Exclusion of staff • Handwashing • Accommodating guests • Hotel Response Team who arrive ill to the hotel (even for small hotels) • Communication/reporting • Vulnerable areas to local Medical Officer of (kitchens, food Health preparation/storage • Sickness log areas, communal areas, • Encouraging reporting of guests’ rooms) sickness by guests • Surfaces touched by hand 31
Preparedness in Hotel Setting Training • Proper training of staff will do more to limit the impact of norovirus in a hotel than ANY OTHER MEASURE • Management should provide training for staff on outbreak identification and control • A specially selected, dedicated ‘Hotel Response team’ should be identified and trained 32
Preparedness in Hotel Setting Communication • A Hotel policy on communication in the event of an outbreak should be devised covering – Guests in residence – Intending guests – Local GPs – Local MOH – Local EHOs – Other businesses (e.g. coach operators/laundry companies) 33
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