Emilio DeBess DVM, MPH Epidemiologist Acute and Communicable Disease Prevention

Transcription

1 Emilio DeBess DVM, MPH Epidemiologist Acute and Communicable Disease Prevention

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3 The Historical Norovirus Caliciviruses: Norovirus & Sapovirus Norovirus Outbreaks in Oregon Long Term Care Facilities Questions? 3

4 Norovirus is a genus of genetically diverse single-stranded RNA, nonenveloped viruses in the Caliciviridae family. The known viruses in the genus are all considered to be the variant strains of a single species called Norwalk virus. 4

5 The viruses are transmitted by fecally contaminated food or water; by personto-person contact; and via aerosolization of the virus and subsequent contamination of surfaces. Noroviruses are the most common cause of viral gastroenteritis in humans, and affect people of all ages. 5

6 Norwalk, Ohio: the Outbreak 6

7 Bronson-Norwalk Township School Halloween

8 In October 1968, an outbreak of acute gastroenteritis among students and teachers in an elementary school in Norwalk, Ohio was investigated by the Centers for Disease Control and Prevention. 8

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10 During a two-day period, 50% of the students and teachers (116 of 232) developed a gastrointestinal illness with a secondary attack rate of 32% among contacts of primary cases. Vomiting in 90% of cases and diarrhea in 38% of affected individuals, and the duration of illness was typically 12 to 24 h. Lab tests did not reveal an etiological agent. 10

11 : The Laboratory of Infectious Diseases (LID) at the National Institutes of Health (NIH) embarks on an intense search for a non-bacterial (viral) etiological agent of acute gastroenteritis. 11

12 June 1972: The 27-nm virus-like particle is discovered by the use of immune electron microscopy, from an infectious stool filtrate derived from an outbreak of gastroenteritis in an elementary school in Norwalk, Ohio. It is described as a small round-structured virus (SRSV). 12

13 1975: CDC creates the Vessel Sanitation Program (VSP) to minimize the risk for gastrointestinal disease among passengers and crew aboard ships by assisting the cruise ship industry in developing and implementing comprehensive environmental health programs. Today, the VSP is an important organization in the surveillance and prevention of norovirus outbreaks. 13

14 October 1977: Sapporo virus is first detected during a gastroenteritis outbreak in a home for infants in Sapporo, Japan. It is distinguished by its typical surface morphology. 14

15 1990: The norovirus genome is finally cloned and sequenced, allowing its classification in the Caliciviridae family. 15

16 1992: Sapoviruses are officially identified as genetically distinct from noroviruses. This is accomplished through the cloning and initial genetic characterization of a genome of human calicivirus with classical morphology and comparison with the cloned genome of Sapporo/82/Japan. 16

17 : 95/96-US strain of Norwalk-like viruses cause 60 outbreaks in geographically distant locations within the US and are identified in an additional 7 countries on 5 continents during the same period. 17

18 November 2003: Spanish authorities close the border with the British colony of Gibraltar before the arrival of a virus-stricken cruise ship carrying some 2,000 passengers. More than 400 passengers on the ship fell ill with a norovirus after the ship left Southampton, England, for a Mediterranean voyage on Oct

19 Virus has been known since 1968 Picturesque names Small round structured virus Winter vomiting disease Norwalk virus Epidemiology has changed dramatically since 2002 Wrecks havoc in long term care facilities 19

20 non-enveloped SS-RNA viruses Caliciviruses Vesivirus Norovirus Lagovirus Sapovirus Group 1 Norwalk Desert Shield more Group 2 Farmington Hills Hunter Minerva New Orleans Sydney** Other Group 1 Houston Manchester more Group 2 Cruise Ship London Bristol more Group 3 poultry Group 4 Osaka Angelholm more

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22 Why are we suddenly having so many gastro outbreaks? Norovirus strain replacement GII.4 Sydney

23 waterborne outbreaks: Arizona, Lawson et al., 1988 foodborne outbreaks: Louisiana, Kohn et al., 1995 military outbreaks: Iraq, Bailey et al., 2005 maritime outbreaks naval: Persian Gulf, Sharpe et al., 1995 cruise ships: United States, Widdowson et al., 2004 long term care facility outbreaks Oregon,

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25 Characteristics of caliciviruses: Very low infectious dose Stable in the environment High percentage of vomitters leads to widespread environmental contamination Easy transmission from person-to-person

26 Caliciviruses: Norovirus & Sapovirus 26

27 Classic profile of signs and symptoms Signs (residents and staff, 03-12) Diarrhea 86% Vomiting 72% pathognomonic Fever 16% Symptoms (staff only, 2003 data only) Cramps 67% Nausea 78% Myalgia 42% Fatigue 80%

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30 Norovirus a chronic problem in nursing homes, longterm care facilities in Oregon. 30

31 Acute gastroenteritis (AGE): acute-onset vomiting, diarrhea, or both without another apparent cause. AGE outbreaks in LTCFs and hospitals: General definition: an "unusual" number of patients, residents or employees with AGE clustered by time and place Working definition: two or more patients, residents or employees in the same LTCF or on the same hospital unit with AGE onset dates within 96 hours of each other (two incubation periods of most gastroenteritis agents) of each other Lab-confirmed AGE outbreak: 2+ stool samples that test positive for the same pathogen "Unexplained" AGE outbreak: 4+ stool samples that test negative for any pathogen (all unexplained AGE outbreaks will now be tested for sapovirus, a Calicivirus similar to norovirus) 31

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35 200 Farmington Hills strain emerges 2002 Sakai & Minerva strains emerge 2006 New Orleans strain emerges 2009 Sydney strain emerges All noro outbreaks LTCF noro outbreaks

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37 August, 2012 September, 2012 October, 2012 November, 2012 December, 2012 January, 2013 February, 2013 March, 2013 April, 2013 May, 2013 long term care retirement school restaurant/deli other 37

38 August, 2012 September, 2012 October, 2012 November, 2012 December, 2012 January, 2013 February, 2013 March, 2013 April, 2013 May, 2013 GI GII.6 GII.4 New Orleans GII.4 Sydney other GII 38

39 Long term care facilities Organizational chart w/ numbers & percentages of residents Department of Human Services Office of Licensing & Regulatory Oversight Community-based Care (CBC) 36,081 residents Nursing Facilities (NF) 12,205 (34%) Assisted Living Facilities (ALF) 14,275 (40%) Residential Care Facilities (RCF) 9,601 (26%)

40 Long term care facilities Organizational chart w/ numbers & percentages of residents & outbreaks* Department of Human Services Office of Licensing & Regulatory Oversight Community-based Care (CBC) 36,081 residents 917 outbreaks* Nursing Facilities (NF) 12,205 (34%) Assisted Living Facilities (ALF) 14,275 (40%) Residential Care Facilities (RCF) 9,601 (26%) 365 (39%) 202 (22%) 338 (37%) * (YTD)

41 Norovirus cases, norovirus incidence rates, October 13, 2011 thru May 20, 2013 DATA & STATS DETAILS Cases (numerator): collected by LTCFs on the Gastroenteritis Case Log; entered in Case Log Database Case definition: resident or staff w/ vomiting, diarrhea or both from thru ; lab-confirmed, epi-linked to lab-confirmed case, or case in a norovirus-like outbreak Population (denominator): number of beds as a proxy for the number of residents adjusted for partial years Caveat lector: incidence rates are underestimated (too low) Case counts incomplete Occupancy of beds < 100%

42 Oregon Norovirus Watch : Norovirus cases organizational chart w/ numbers & percentages of facilities & outbreaks Lab-confirmed and presumptive (epi-linked) norovirus cases October 13, 2011 thru May 20, 2013 Residents Staff Total Cases Frequency Rate per 100 residents Frequency Assisted Living Facilities % Residential Care Facilities % Nursing Facilities 870 6% Total % Comparison Campylobacteriosis (Oregon, 2011): 25.6/100,000 or.025% of Oregonians

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44 Up-to-date info about Calicivirus outbreaks in Oregon DiseasesAZ/Pages/disease.aspx?did=110 Investigative guidelines for local health NS/COMMUNICABLEDISEASE/OUTBREAKS/Pages/gast ro.aspx CDC norovirus page 44

45 Emilio DeBess DVM, MPH Epidemiologist , Local Health Department Contact information at: 45

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