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Danae Bixler, MD, MPH Division of Infectious Disease Epidemiology.

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Presentation on theme: "Danae Bixler, MD, MPH Division of Infectious Disease Epidemiology."— Presentation transcript:

1 Danae Bixler, MD, MPH Division of Infectious Disease Epidemiology

2 Objectives Describe 2009 outbreaks Lessons learned Prompt reporting Laboratory confirmation / diagnosis Outbreak investigation as problem-solving Types of common outbreaks Enteric outbreaks Rash illness ‘Other’ Vaccine preventable disease outbreaks Respiratory outbreaks Healthcare associated outbreaks Relate findings to the 13 steps of outbreak investigation. 2

3 Steps of Outbreak Investigation 1. Prepare for field work 2. Establish the existence of an outbreak 3. Verify the diagnosis 4. Construct a working case definition 5. Find cases systematically and record information 6. Perform descriptive epidemiology 3

4 Steps of Outbreak Investigation (2) 7. Develop hypotheses 8. Evaluate hypotheses epidemiologically 9. As necessary, reconsider, refine, and re-evaluate hypotheses 10. Compare and reconcile with laboratory and/or environmental studies 11. Implement control and prevention measures 12. Initiate or maintain surveillance 13. Communicate findings 4

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6 Summary Data (provisional) 123 outbreaks reported 98 (80%) confirmed as outbreaks or clusters 39 (71 %) counties reported one or more outbreak- related cases Jurisdiction 90 (92 %) West Virginia 3 (3 %) multi-state / West Virginia = lead investigator 4 (4 %) multi-state / other state = lead investigator 6

7 Counties Reporting Outbreak-Related Cases (provisional / includes multi-county outbreaks) CountyNumber of Outbreaks Reported Kanawha16 Wood12 Mercer6 Putnam6 Fayette5 Raleigh4 Logan4 Marshall4 Monongalia4 Ohio4 Preston4 7

8 Counties Reporting Outbreak-Related Cases (provisional / includes multi-county outbreaks) CountyNumber of Outbreaks Reported Cabell3 Mason3 Pleasants3 Randolph3 Roane3 Berkeley2 Gilmer2 Greenbrier2 Lewis2 Marion2 Monroe2 Wayne2 8

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10 Timeliness of Reporting – Summary Statistics (provisional) N = 85 observations (87 %) Mean 42 hours Median 1 hour Range = 0 to 662 hours 10

11 Timely reporting of outbreaks Laboratory support Technical support Case definitions / diagnosis Descriptive epidemiology Cohort or case-control studies Communications support 11

12 Timely reporting of outbreaks Required under: Reportable disease rule Threat preparedness funding stream Program plan 12

13 Timeliness of Reporting (provisional / multi-county outbreaks excluded) Counties that report more than one outbreak reported outbreaks more rapidly: 13 Number of Outbreaks Reported Number of Outbreaks Mean Time elapsed (hours) Median Time elapsed (hours) >

14 Reported Outbreaks by Type, West Virginia, 2009 (provisional) Outbreak TypeFrequencyPercent Respiratory 5354% Enteric 2930% Rash 99% Other 77% Total 98100% 14

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16 Enteric Outbreak Summary (provisional) N = 29 Reported by 23 (42%) counties Jurisdiction: 24 (83%) West Virginia 1 (3%) multi-state; West Virginia = lead investigator 14 cases gastroenteritis N = 4 (14%) multi-state outbreaks; CDC / other state = lead 16

17 West Virginia Enteric Outbreaks (provisional) 24 (83%) West Virginia enteric outbreaks 1 (4%)Salmonella enteritidis 22 (92%) Norovirus or acute gastroenteritis 18 (82%) in nursing homes / healthcare facilities 17 (77%) person-to-person transmission 1 (4%) rotavirus 17

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19 Norovirus NEJM, 2009; 361:1776 Acute onset vomiting and/or diarrhea Reservoir = humans Highly efficient transmission 18 – 1000 viral particles 30% secondary attack rate Droplets Fomites Person-to-person Environmental contamination 19

20 Norovirus (2) NEJM, 2009; 361:1776 Viral shedding Precedes onset 30% After recovery (up to 8 weeks) Environmental stability 0° C to 60° C Surfaces Recreational and drinking water Food items such as raw oysters, fruits, vegetables Lack of long-term immunity Viral mutation 20

21 Norovirus NEJM, 2009; 361:1776 Prevention and Control Isolation of ill persons Enforce personal hygiene Environmental decontamination Use of alcohol-based hand sanitizer promising 21

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23 Acute Gastroenteritis 1. Prepare for field work 2. Establish the existence of an outbreak 3. Verify the diagnosis 4. Construct a working case definition 5. Find cases systematically and record information 6. Perform descriptive epidemiology 7. Develop hypotheses 8. Evaluate hypotheses epidemiologically 9. As necessary, reconsider, refine, and re-evaluate hypotheses 10. Compare and reconcile with laboratory and/or environmental studies 11. Implement control and prevention measures 12. Initiate or maintain surveillance 13. Communicate findings 23

24 Acute Gastroenteritis 2. Establish the existence of an outbreak 3. Verify the diagnosis. 4. Construct a working case definition 24

25 Acute Gastroenteritis 2. Establish the existence of an outbreak 3. Verify the diagnosis. 4. Construct a working case definition 25

26 26 6. Perform descriptive epidemiology.

27 27 6. Perform descriptive epidemiology. 7. Develop hypotheses.

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30 Salmonella Bacterial cause of diarrhea, fever, abdominal cramps Most persons recover without treatment. Severe illness: Elderly Infants and young children Immunocompromised persons Multi-state outbreaks Widely distributed Commercial food products Produce Detection by pulse-net 30

31 Multi-state Salmonella Outbreaks Pulsenet Send isolates to OLS for PFGE 2008 Salmonella typhimurium / peanut butter National update 2009 March: Salmonella typhimurium / Virginia April: Salmonella St. Paul / multistate June: Salmonella enteritidis / Virginia June: Salmonella oranienburg / Louisiana 31

32 Salmonella typhimurium outbreak MMWR, 2009; 58: Nov 25, 2008 investigation started. Multiple institutional outbreaks … traceback demonstrated one common food: King Nut peanut butter Step 7: Develop hypotheses Case-control implicated peanut butter Step 8: Evaluate hypotheses epidemiologically. Jan 9, 2009, Minnesota Department of Agriculture isolated the outbreak strain from King Nut Peanut Butter. Step 10: Compare and reconcile with laboratory and/or environmental studies. 32

33 Ongoing investigation MMWR, 2009; 58: Multiple institutional outbreaks … King Nut peanut butter was distributed to institutions. Many ill persons did not eat peanut butter in institutions. Step 9. As necessary, reconsider, refine and re-evaluate hypotheses. Second series of case-control studies: pre-packaged peanut butter crackers. Step 8: Evaluate hypotheses epidemiologically. Intact packages of crackers yielded the outbreak strain Step 10: Compare and reconcile with laboratory and/or environmental studies. 33

34 34 MMWR, 2009; 58:85-90.

35 35 MMWR, 2009; 58:85-90.

36 36 Number of infections (N = 226*) with the outbreak strain of Salmonella Saintpaul associated with eating alfalfa sprouts, by date of illness onset --- United States, February--April 2009 * as of May 1, 2009 MMWR, 2009; 58:

37 Number of infections (N = 228*) with the outbreak strain of Salmonella Saintpaul, associated with eating alfalfa sprouts, by state --- United States, February--April 2009 *as May 1, 2009 MMWR, 2009; 58:

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39 Rash Illness Outbreaks (provisional) 4 Human parvovirus B-19 (“Fifth Disease”) schools 3 scabies Nursing home Detention center Homeless shelter 2 varicella schools 39

40 Erythema Infectiosum (Parvovirus B-19) (“Fifth Disease”) Mild prodrome Fever 15-30% ‘Slapped face’ rash Rash Symmetric, maculopapular, reticular, often pruritic Trunk Moves peripherally to arms, buttocks, thighs Fluctuates / recurs 40

41 Parvovirus B-19 (“Fifth Disease”) 41

42 Parvovirus B-19 (“Fifth Disease”) Hardin MD/University of Iowa and CDC 42

43 Parvovirus B-19 adapted from 2009 Redbook ConditionsUsual Hosts Erythema InfectiosumHealthy children Polyneuropathy syndromeHealthy adults (female > male) Chronic anemia / pure red cell aplasia Immunocompromised adults Transient aplastic crisisPeople with hemolytic anemia (e.g., sickle cell) Hydrops fetalis / congenital anemia Fetus (1 st half of pregnancy) Persistent anemiaImmunocompromised people 43

44 Parvovirus B-19 Erythema Infectiosum Transmission: contact with respiratory tract secretions Secondary spread 50% in household contacts 20% in school and daycare Infectious period Prior to rash onset No exclusion of children with rash 44

45 Parvovirus B-19 Erythema Infectiosum Control Hand hygiene Dispose of tissues Counsel pregnant women Low risk Exclusion not recommended Evaluation per OB/GYN 45

46 Parvovirus B-19 Outbreaks 1. Prepare for field work 2. Establish the existence of an outbreak 3. Verify the diagnosis 4. Construct a working case definition 5. Find cases systematically and record information 6. Perform descriptive epidemiology 7. Develop hypotheses 8. Evaluate hypotheses epidemiologically 9. As necessary, reconsider, refine, and re-evaluate hypotheses 10. Compare and reconcile with laboratory and/or environmental studies 11. Implement control and prevention measures 12. Initiate or maintain surveillance 13. Communicate findings 46

47 Scabies Cleaveland Clinic J Med, 2008; 75: Papules Excoriations Burrows Nodules 47

48 Atypical Scabies N Engl J Med, 2006; 345:

49 Management of Scabies Outbreaks Nosocomial / institutional outbreaks: Contact precautions 24 hours after treatment 10 days after treatment of crusted scabies Make a secure diagnosis Consider dermatology consultation Identify infested persons Treat infested persons and contacts Patients and staff Environmental control measures 49

50 Environmental Management of Scabies Infestation (CDC) WhatUsed by WhomManagement Items used within 3 days: Bedding Clothing Towels Infested person Household and sexual contacts Persons with skin-to-skin contact Wash in hot water and dry in a hot dryer OR Dry clean OR Seal in a plastic bag for at least 72 hours Insecticide sprays and fumigants NOT recommended Mites do not survive more than 3 days away from human skin 50

51 Scabies Outbreaks 1. Prepare for field work 2. Establish the existence of an outbreak 3. Verify the diagnosis 4. Construct a working case definition 5. Find cases systematically and record information 6. Perform descriptive epidemiology 7. Develop hypotheses 8. Evaluate hypotheses epidemiologically 9. As necessary, reconsider, refine, and re-evaluate hypotheses 10. Compare and reconcile with laboratory and/or environmental studies 11. Implement control and prevention measures 12. Initiate or maintain surveillance 13. Communicate findings 51

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53 Other Outbreaks (provisional) Invasive methicillin sensitive Staphylococcus aureus Healthcare associated Hepatitis B Healthcare associated 2 Conjunctivitis Nursing home Elementary school 1 skin infection Day care 2 MRSA Nursing home Football team 53

54 Conclusions Prompt reporting of outbreaks Assistance with: Laboratory diagnosis Clinical diagnosis Control measures Required by/for: Reportable disease rule Program plan Threat preparedness 54

55 Lessons Learned Outbreak investigation process Problem-solving Establish the existence of an outbreak … Verify the diagnosis … Control measures … Communicate findings … Laboratory confirmation Collaboration between local, regional, state … CDC … WHO Stay tuned: Salmonella enteritidis Healthcare associated outbreaks Respiratory outbreaks Varicella 55


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