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Use of Epidemiology in Field Settings and Experiences on the Front Lines of Public Health: The Life of an EIS Officer Jennifer Gordon Wright, DVM, MPH,

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Presentation on theme: "Use of Epidemiology in Field Settings and Experiences on the Front Lines of Public Health: The Life of an EIS Officer Jennifer Gordon Wright, DVM, MPH,"— Presentation transcript:

1 Use of Epidemiology in Field Settings and Experiences on the Front Lines of Public Health: The Life of an EIS Officer Jennifer Gordon Wright, DVM, MPH, DACVPM Centers for Disease Control and Prevention

2 Public Health “is what we, as a society, do collectively to assure the conditions in which people can be healthy.” Institute of Medicine, The Future of Public Health, 1988

3 The Veterinary Oath Being admitted to the profession of veterinary medicine, I solemnly swear to use my scientific knowledge and skills for the benefit of society through the protection of animal health, the relief of animal suffering, the conservation of animal resources, the promotion of public health, and the advancement of medical knowledge.

4 Emerging Zoonoses 1415 species of infectious agents reported to cause disease in humans –Viruses, prions, bacteria, rickettsia, fungi, protozoa, helminths –868 (61%) are known to be zoonotic 175 species considered “emerging” –132 (75%) are known to be zoonotic Taylor et al. Risk factors for disease emergence. 2001, Philosophical Transactions, The Royal Society, London

5 The Long and Winding Road… Bachelor of Science in Microbiology, Auburn University –Interest in working at CDC, but in what capacity? DVM from Auburn University, 1998 –Planned a career in small animal practice or with a drug company –Turning point – a lecture in sophomore PH lecture about a human case of plague Went into practice for a few years –Found the EIS program while searching the web for jobs Began MPH work in 2000, worked at CDC Entered EIS in July 2002

6 History of CDC Communicable Disease Center founded in Atlanta by Dr Joseph W Mountin 400 employees, mostly engineers and entomologists working on malaria prevention –Original focus on vectorborne and zoonoses Growing awareness that expansion to all communicable diseases was necessary

7 CDC today One of 13 components of DHHS >8000 employees –Headquarters – Atlanta, Morgantown, Ft. Collins, Cincinnati, Hyattsville –State health departments International reputation Applies research and findings to improve daily lives Respond to health emergencies Not just infectious diseases –Chronic diseases, injuries, workplace hazards, disabilities, environmental health threats

8 How CDC operates Jurisdiction over: –Cruise ships docking in US ports –Importation of people/animals with communicable disease Otherwise, need invitation of the state or reservation to assist

9 Veterinarians at CDC As of December 2005

10 What is the EIS Program? Epidemic Intelligence Service (aka “Disease Detectives”) Established in 1951 Mission: To prevent & control communicable diseases A 2 year training program in applied epidemiology Domestic and International Service –Respond to Requests for Epidemiologic Assistance

11 EIS continued officers, 6-9% are veterinarians Applications are due in October for the following year’s class Additional training or experience in public health encouraged prior to application

12 So What is Epidemiology? The science of studying patterns of disease in populations and the factors that determine such patterns and the utilization of such knowledge for diagnosis, control, and prevention

13 So What is Epidemiology? The science of studying patterns of disease in populations and the factors that determine such patterns and the utilization of such knowledge for diagnosis, control, and prevention The study of why some get sick and some don’t

14 So What is Epidemiology? The science of studying patterns of disease in populations and the factors that determine such patterns and the utilization of such knowledge for diagnosis, control, and prevention The study of why some get sick and some don’t The study of skin…

15 Epidemic Dorland’s defines as: –Disease attacking many people at the same time, widely diffused and rapidly spreading –Excessive occurrence of disease

16 Descriptive epidemiology Who –is affected (gender, age, race/ethnicity) What –disease is causing the problem Where – is outbreak occurring When –did the outbreak occur

17 Analytic epidemiology Why –Did the outbreak occur How –Risk factors for illness –Examples: Eat a certain food item Swam in contaminated lake Exposure to ticks

18 Establishing Causality (continued) Hill’s Causal Criteria Strength of association –Magnitude of the risk (Odds Ratio, Relative Risk) Temporality –Exposure must precede outcome Dose-response –The greater the dose the greater the risk Consistency –The association between risk factor and outcome is consistent across studies, samples, populations, etc.

19 Establishing Causality (continued) Hill’s Causal Criteria Biological plausibility –Association is biologically rational Coherence –Association is consistent with pathogenesis of disease, similar known associations exist Specificity –one exposure equals one outcome

20 Outbreak investigation Establish a case definition (epi vs. lab) Find cases Determine if an epidemic has occurred Characterize the epidemic in space and time Investigate risk factors Formulate/test hypotheses (case-control) Design control/prevention strategies Monitor and evaluate for recurrence

21 Risk factors Specific exposures or characteristics associated with disease, i.e. age, gender, breed, race, nutritional status, physiological status, activities, employment, housing, etc.

22 Characterizing risk factors Relative Risk Odds Ratio Attributable Risk

23 AB CD Disease YesNo A + B Risk Factor/exposure Yes NoC + D A + CB + D The Association between a Risk Factor and a Disease Odds Ratio AD BC Risk Ratio A A+B divided by C C+D

24 Come Sail Away: Cruise Related Illness, Caribbean, 2002

25 Vessel Sanitation Program (VSP) 24 hours before arrival in US port ship physician must report number of passengers seen for acute gastroenteritis (AGE) > 2.0% of passengers/crew with AGE – special report > 3.0% of passengers/crew with AGE – outbreak investigation

26 Timeline September 28, 2002 –1980 passengers, 941 crew October 2, 2002 –79 (4.0%) of 1980 passengers with acute gastroenteritis (AGE) –No crew reported illness October 3, 2002 –CDC team boarded the ship in the Cayman Islands

27 Objectives Determine the etiologic agent Determine the source of the outbreak Implement control measures

28 Methods Epidemiologic Case Finding -GI logs -Survey Case-control study -Survey data Illness onset Symptoms of illness Illness-associated risk factors Other  Environmental inspection  Stool collection -Laboratory testing Viral Bacterial

29 Survey Case Definition Diarrhea (3 or more loose or watery bowel movements in a 24-hour period) OR Vomiting with 1 of the following: Abdominal cramps, nausea, fever AND Onset September 28 - October 4, 2002

30 Case-Control Definitions Case Illness onset 9/29 or 9/30 Excluded secondary cases: –Persons who met the case definition but cabin mate had onset of illness > 24 hours prior Control Persons on the cruise who did not report diarrheal illness, vomiting or accompanying symptoms between September 28 and October 4, 2002

31 Results

32 Laboratory Results 4 of 11 specimens – Norovirus

33 Norovirus ssRNA, Caliciviridae Norwalk-like virus Incubation –24 to 48 hours Acute onset –Vomiting, non-bloody diarrhea Duration –24 to 60 hours Asymptomatic – 30% Transmission – easy

34 Survey Results Response Rate –1897 (96%) of 1980 Attack Rate –356 (19%) of 1897 We randomly selected 83 ill persons and 152 controls from our returned surveys –55 cases: onset September 29 –28 cases: onset September 30

35 Cases of vomiting or diarrhea among passengers and crew, cruise ship C, by date of onset (6-hour periods), Sept 27 to Oct 4, 2002 Date of embarkation

36 Date of embarkation Case Control Study period Date of embarkation Case Control Study period Cases of vomiting or diarrhea among passengers and crew, cruise ship C, by date of onset (6-hour periods), Sept 27 to Oct 4, 2002

37 Descriptive Results Age –Cases: median 54 years –Controls: median 51 years Gender –Cases: males 43% –Controls: males 42%

38 Risk Factors Significant –Restaurants –Food –Activities Not Significant –Unbottled water consumption

39 Restaurants 4 main restaurants –1 and 2 shared a galley –3 and 4 shared a galley 6 specialty restaurants –Additional cost to eat in these

40 Restaurant-Illness associations RestaurantOnset 9/29 (n=55) Lunch 9/28 (Rest 1 & 2) number of cases OR (95% CI) p-value 48 (87%) 2.5 (1.0, 5.9) Dinner 9/28 (Rest 3) number of cases OR ( 95% CI) P-value 22 (27%) 2.5 (1.3, 4.8) 0.007

41 Food, Restaurants 1 and 2 onset of illness Sept 29 Lunch (9/28)Onset 9/29 (n=48) Seafood Salad number of cases OR (95% CI) P-value 24 (50%) 2.5 (1.5, 5.6) Roasted Steamship (beef) number of cases OR (95% CI) P-value 8 (17%) 5.4 (1.5, 18.7) 0.004

42 Activities Onset of illness Sept 30 Onset 9/30Cases (n=28) Odds Ratio 95% CIP-value Casino (9/29) 13 (46%)3.41.4, :45 Concert (9/29) 13 (46%)3.81.6, Hot tub (9/29) 8 (29%)2.81.1,

43 Limitations Number of food items served –>200 in 2 days Time between exposure and survey –6 days after suspect foods served Passenger discussions Asymptomatic infections as high as 30% –Controls could have been infected

44 Discussion Foodborne –Galley worker reported illness 9/27 –Distributor prior to bringing on ship Norovirus outbreak Illness onset on Sept 29 th –due to a food item Illness onset on Sept 30 th –Person-to-person spread Aggressive control measures by cruise line may have led to less person-to-person spread than in other outbreaks

45 Control Measures Before CDC team arrival –Heightened disinfection: 1000 ppm chlorine on hard surfaces –Food serving procedures: gloves, no self serve buffets After CDC team arrival –Soft fabric disinfection –Cruise line mandated any ill passenger be confined to cabin for 24 hours

46 Recommendations Prompt and aggressive control Environmental contamination Food safety –Proper handling –Hand washing Strategies to improve employee reporting of illness

47 First Outbreak of Monkeypox in the Western Hemisphere, 2003

48 Monkeypox Orthopoxvirus, related to smallpox Restricted to Africa (West Africa, DRC) Zoonotic disease –Wildlife reservoir unknown –Antibodies to virus found in rodents –Primates and humans accidental hosts Clinically resembles smallpox –Vesicular rash –Lymphadenopathy –Case fatality < 15% –Limited potential for human-to-human spread –9 day incubation period

49 5/ 11/03 6/1/036/2/036/3/036/4/036/5/036/6/036/7/036/8/036/9/036/ 10/03 6/ 11/03 5/ 14/035/ 15/035/ 16/035/ 17/035/ 18/03 5/ 27/03 5/ 28/035/ 29/035/ 30/035/ 19/035/ 20/035/ 21/035/ 22/035/ 23/035/ 24/035/ 25/035/26/035/ 13/035/ 12/03 5/ 31/03 Child ill On May 20, 2003 a 3 year old Wisconsin girl became ill with fever and presumed cellulitis. Purchase PD at swap meet Family had purchased 2 PDs from a swap meet on May 11 th. Lesions appeared at site of a bite from a sick PD on May 13th. PD bites child Multistate Monkeypox Outbreak, 2003

50 Skin Lesions, Index Case (3 year old child) Marshfield Clinic, WI DAY 11

51 Purchase PD at swap meet PD bites child Child ill 5/ 11/03 6/1/036/2/036/3/036/4/036/5/036/6/036/7/036/8/036/9/036/ 10/03 6/ 11/03 5/ 14/035/ 15/035/ 16/035/ 17/035/ 18/03 5/ 27/03 5/ 28/035/ 29/035/ 30/035/ 19/035/ 20/035/ 21/035/ 22/035/ 23/035/ 24/035/ 25/035/26/035/ 13/035/ 12/03 5/ 31/03 Mother ill On May 26 th, the child’s mother became ill. Dealer ill On May 23 rd, the exotic animal dealer that sold the family their PDs became sick.

52 Wisconsin Animal Dealer, Primary lesion

53 Purchase PD at swap meet Mother ill Dealer ill Child ill 5/ 11/03 6/1/036/2/036/3/036/4/036/5/036/6/036/7/036/8/036/9/036/ 10/03 6/ 11/03 5/ 14/035/ 15/035/ 16/035/ 17/035/ 18/03 5/ 27/03 5/ 28/035/ 29/035/ 30/035/ 19/035/ 20/035/ 21/035/ 22/035/ 23/035/ 24/035/ 25/035/26/035/ 13/035/ 12/03 5/ 31/03 The Marshfield Clinic grew virus from mother and PD identified as a poxvirus by EM. Poxvirus on EM, WI DOH notified The WI DOH was notified of illnesses in all parties, initiated traceback on Prairie Dogs and notified CDC. PD bites child

54 Purchase PD at swap meet Mother ill Dealer ill Child ill 5/ 11/03 6/1/036/2/036/3/036/4/036/5/036/6/036/7/036/8/036/9/036/ 10/03 6/ 11/03 5/ 14/035/ 15/035/ 16/035/ 17/035/ 18/03 5/ 27/03 5/ 28/035/ 29/035/ 30/035/ 19/035/ 20/035/ 21/035/ 22/035/ 23/035/ 24/035/ 25/035/26/035/ 13/035/ 12/03 5/ 31/03 Monkeypox confirmed at CDC by PCR CDC confirmed monkeypox in samples from mother and PD. Executive Order FDA/CDC CDC and FDA issued a joint emergency order prohibiting trade and movement of PDs and African rodents. Poxvirus on EM, WI DOH notified PD bites child

55

56 47 human cases in 5 states All cases reported contact with sick prairie dogs No clear person-to-person spread High hospitalization rate for quarantine/infection control issues Over 25% of cases occurred in veterinary staff First outbreak of monkeypox in humans outside Africa 2003 Monkeypox Outbreak Characteristics

57 Animal Traceback All sick prairie dogs were traced to an IL dealer IL dealer had African rodents (Gambian rats and dormice) on the premises Traced movements of all prairie dogs and African rodents Tracing capabilities limited –Cash sales, often no record –Trade at swap meets- widespread distribution –Dealer recall limited –Exposure without ownership (contact in store…)

58 Movement of Imported African Rodents to Animal Distributors and Distribution of Prairie Dogs from Point of Infection Rodent Shipment from Accra, Ghana TX 1** 50 Gambian rats (GR) 53 rope squirrels (RS) 2 brush-tailed porcupines (BTP) 47 sun squirrels (SS) 100 striped mice (SM) ~510 dormice (DM) 4/9/03 NJ RS, BTP SS TX 3 RS, SM DM 4/11/03 4/17/03 IA † GR, DM 4/16/03 TX 4 DM TX 5 DM 4/21/03 TX 6 SS, SM DM 4/26/03 TX 2 GR ? TX 8 DM TX 7 DM 4/28/03 TX 9 DM ? 4/28/03 Japan DM TX 10 DM 4/29/03 5/18/03 MN DM WI DM 6/1/03 1 PDs traced IL 2 DM 5/12/03 IL 1 § GR, DM 200 prairie dogs (PDs) in existing inventory MI No human cases SC No human cases MO Human cases: 2 confirmed KS Human cases: 1 confirmed IN Human cases: 7 confirmed 9 probable/ suspect IL ‡ Human cases: 8 confirmed 4 probable/ suspect WI Human cases: 17 confirmed 22 probable/ suspect 1 PD traced 11 PDs traced 24 PDs traced 14 PDs traced 42 PDs traced MMWR July 2003 June 2003 lab confirmation: diseased animals derived from shipment

59 Gambian Giant (Pouched) Rat Rope Squirrel Sun Squirrel Dormouse Striped Mouse Evidence of monkepox infection in laboratory testing

60 Reasons for the 2003 Monkeypox Outbreak Unrestricted importation of animals from Africa –Wild caught animals with unknown history Exotic pet trade allows rapid movement of animals –Not regulated by federal statues –No requirements to maintain records Human medicine is not familiar with monkeypox –Did not recognize lesions as smallpox-like –Delayed reporting of “unusual illness” to state authorities

61 Thyrotoxicosis South Dakota, June 1985 Eight persons aged years (5 men) Symptoms: anxiety, palpitations, dyspnea, weight loss, tachycardia Signs: elevated T4, low RAIU Onset: May - June 1985

62

63 Background Cases clustered in two SD towns (near MN) Interviewed eight patients No common exposures Drew blood from patients and family Tests run

64 Preliminary Investigation Case-finding –33 additional patients who in the past year had High T4 Low RAIU Cases clustered around Luverne, MN Results from other 8 patients' families: –75% of asymptomatic family members had elevated T4s

65 Further Findings Total: 121 cases Age range: 0-76 years Sex: 62 male, 59 female Onset: April 1984-August 1985 Location: Clustered around MN-SD border

66 Case-Control Study Cases: first patient in household Controls: same phone exchange Questions: – History of viral illness – Ingestion of Iodine-containing food – Medications – Toxic exposures – Food additives/Health food products – Contacts with others who were ill

67 Additional Findings New patient from outside the area – Shopped at a grocery store in area – All foods national brands except: Fresh chicken eggs Beef trimmings from plant A in Luverne, MN One family: all members were cases except one boy (vegetarian) Case-control study implicated beef trimmings from Plant A

68 Summary "Before April 1983 thyroid glands were selectively removed and sold for use in the manufacture of thyroid extract. After that time, 'gullet trimming' was employed to harvest muscle from the bovine larynx...motion allowed portions of both lobes of the thyroid gland to be inadvertently included in the muscle trimming...“ Thyroid was being ground up with muscle and ingested as part of ground beef

69 Salmonellosis January 1981 call to CDC: –36 cases Salmonella munchen in Jefferson Co., OH since mid-December cases with same serotype in Lansing, MI

70 Descriptive Epidemiology –Age range: 1 month - 76 years –28% of patients aged years –Located in 3 disparate neighborhoods in Jefferson County, OH

71 Investigation No common exposures among cases except ham Brands/Types of hams different All ham cultures negative Other activities to consider? Ongoing source of infection? Weekly stool cultures all positive One turned negative -- pregnant woman

72 Pregnant Woman - Key Interviewed pregnant woman for activities (in which she no longer participated)

73 Pregnant Woman - Key Interviewed pregnant woman for activities (in which she no longer participated) –Smoking –Drinking alcohol –Smoking marijuana

74 “Smoking” Gun… Upon further questioning: –At least one member of each case- household smoked marijuana Marijuana from all households in town positive for S. munchen Biologic plausibility

75 Infection control survey

76 Survey of Veterinary Hospital Infection Control Practices AVMA/CDC collaborative effort Survey –Knowledge –Attitudes –Practices regarding infection control practices –Use of PPE WHY? –To determine current practices –To determine what additional resources are needed

77 Methodology AVMA 2004 Membership list (n=48,548) – Employer codes (n=45,185) –Species Codes Small Animal, Mixed Animal, Equine, Large Animal Randomly selected veterinarians from each category to receive a survey

78 All *SmallMixedEquineLarge Female48%52%27%21%19% < 10 years in practice 26%27%24% Owner58%54%78%66%72% ≥ 40 hours per week 66%61%86% 84% Teaching5%6%0.5%11%10% Mobile Only4%2%3%47%67% Policy (yes)22%24%13%20%11% *weighted population averagePreliminary results

79 Infection control practices All *SmallMixedEquin e Larg e Always wash hands before eat 53%55%47%31%28% May eat in animal areas 86% 91%82%79% May recap needles 93%92%95%98%97% May re-use needles 32%28%52%15%41% *weighted population averagePreliminary results

80 Engage in protective behavior when handling… All*SmallMixedEquineLarge Healthy animal57%58%56%16%76% Animal w- vomiting/diarrhea 25%24%40%52%54% Animal w- neurologic signs 20%16%37%18%62% Feces44% 47%16%69% Urine27%26%34%14%54% Products of parturition 4%5%1% 0% *weighted population averagePreliminary results

81 When looking at veterinarians by years in practice* < 10 year≥10 years Always wash hands53% May eat in treatment area 91%85% Recap needles96%92% Hours per week worked66% Owner of clinic21%71% Bitten in last year50%53% Needlestick in last year71%60% Cut by instrument28%23% *weighted population averagePreliminary results

82 Conclusions Zoonoses are of great importance in human health Veterinarians are often front line of defense, but do not protect selves adequately Need for written guidance for veterinary profession Self-reported behavior not always accurate MPH student thesis analysis of small animal practitioners only demonstrated that males, those in the Midwest and those working in clinics without written infection control policies were more likely to have “poor” infection control practices

83 Compendium Committee Representatives from NASPHV, CDC, academia, AAHA, state and local health departments Tasked to develop written “Universal Precautions” for veterinarians Data from the survey will point to where gaps exist

84 Acknowledgements Jennifer McQuiston, CDC Sherry Jung, Rollins School of Public Health Nina Marano, CDC Doug Hamilton, CDC Marc-Alain Widdowson, CDC American Veterinary Medical Association Dr. John New and Katie Portacci, UT

85


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