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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, DACVPM Centers for Disease Control and Prevention [email protected] 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 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. 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 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 History of CDC • 1946 - 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 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 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 Veterinarians at CDC As of December 2005 State Health Departments (14) Reproductive Health (1) Bioterrorism (2) Injury Prevention (1) AIDS/STD (8) Bacterial Diseases (10) Immunizations (2) Environmental Health (12) Quarantine (2) Office of the Director (6) USDA liaisons (2) Viral Diseases (13) Parasitic Diseases (5) Vectorborne Diseases (4) Laboratory Animal Issues (7) NIOSH (4) 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 EIS continued • 55-75 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 • http://www.cdc.gov/eis/about/about.htm 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 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 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… Epidemic • Dorland’s defines as: – Disease attacking many people at the same time, widely diffused and rapidly spreading – Excessive occurrence of disease Descriptive epidemiology • Who – is affected (gender, age, race/ethnicity) • What – disease is causing the problem • Where – is outbreak occurring • When – did the outbreak occur 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 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. 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 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 Risk factors • Specific exposures or characteristics associated with disease, i.e. age, gender, breed, race, nutritional status, physiological status, activities, employment, housing, etc. Characterizing risk factors • Relative Risk • Odds Ratio • Attributable Risk The Association between a Risk Factor and a Disease Disease Risk Factor/exposure Yes No Yes A B No C D A+C B+D A+B C+D Risk Ratio A A+B divided by C C+D Odds Ratio AD BC Come Sail Away: Cruise Related Illness, Caribbean, 2002 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 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 Objectives • Determine the etiologic agent • Determine the source of the outbreak • Implement control measures 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 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 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 Results Laboratory Results • 4 of 11 specimens – Norovirus 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 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 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 70 60 crew 50 Number Date of embarkation 40 passengers 30 20 10 date and time of illness onset 10/04:12 10/04:00 10/03:12 10/03:00 10/02:12 10/02:00 10/01:12 10/01:00 09/30:12 09/30:00 09/29:12 09/29:00 09/28:12 09/28:00 09/27:12 09/27:00 0 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 Case Control Study period Case Control Study period 70 60 crew 50 Number Date Dateof of embarkation embarkation 40 passengers 30 20 10 date and time of illness onset 10/04:12 10/04:00 10/03:12 10/03:00 10/02:12 10/02:00 10/01:12 10/01:00 09/30:12 09/30:00 09/29:12 09/29:00 09/28:12 09/28:00 09/27:12 09/27:00 0 Descriptive Results • Age – Cases: median 54 years – Controls: median 51 years • Gender – Cases: males 43% – Controls: males 42% Risk Factors • Significant – Restaurants – Food – Activities • Not Significant – Unbottled water consumption 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 Restaurant-Illness associations Restaurant Onset 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) 0.037 Dinner 9/28 (Rest 3) number of cases OR ( 95% CI) P-value 22 (27%) 2.5 (1.3, 4.8) 0.007 Food, Restaurants 1 and 2 onset of illness Sept 29 Lunch (9/28) Seafood Salad number of cases OR (95% CI) P-value Roasted Steamship (beef) number of cases OR (95% CI) P-value Onset 9/29 (n=48) 24 (50%) 2.5 (1.5, 5.6) 0.001 8 (17%) 5.4 (1.5, 18.7) 0.004 Activities Onset of illness Sept 30 Onset 9/30 Casino (9/29) 8:45 Concert (9/29) Hot tub (9/29) Cases (n=28) 13 (46%) Odds Ratio 3.4 95% CI P-value 1.4, 7.8 0.004 13 (46%) 3.8 1.6, 9.0 0.001 8 (29%) 2.8 1.1, 7.2 0.030 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 Discussion • Foodborne – Galley worker reported illness 9/27 – Distributor prior to bringing on ship • Norovirus outbreak • Illness onset on Sept 29th – due to a food item • Illness onset on Sept 30th – Person-to-person spread • Aggressive control measures by cruise line may have led to less person-to-person spread than in other outbreaks 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 Recommendations • Prompt and aggressive control • Environmental contamination • Food safety – Proper handling – Hand washing • Strategies to improve employee reporting of illness First Outbreak of Monkeypox in the Western Hemisphere, 2003 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 Multistate Monkeypox Outbreak, 2003 Purchase PD at swap meet PD bites child Child ill Lesions appeared at site of a bite from a sick PD on May 13th. Family had purchased 2 PDs from a swap meet on May 11th. 6/ 11/03 6/ 10/03 6/9/03 6/8/03 6/7/03 6/6/03 6/5/03 6/4/03 6/3/03 6/2/03 6/1/03 5/ 31/03 5/ 30/03 5/ 29/03 5/ 28/03 5/ 27/03 5/26/03 5/ 25/03 5/ 24/03 5/ 23/03 5/ 22/03 5/ 21/03 5/ 20/03 5/ 19/03 5/ 18/03 5/ 17/03 5/ 16/03 5/ 15/03 5/ 14/03 5/ 13/03 5/ 12/03 5/ 11/03 On May 20, 2003 a 3 year old Wisconsin girl became ill with fever and presumed cellulitis. Skin Lesions, Index Case (3 year old child) Marshfield Clinic, WI DAY 11 Mother ill Dealer ill Purchase PD at swap meet Child ill PD bites child 6/ 11/03 On May 23rd, the exotic animal dealer that sold the family their PDs became sick. 6/ 10/03 6/9/03 6/8/03 6/7/03 6/6/03 6/5/03 6/4/03 6/3/03 6/2/03 6/1/03 5/ 31/03 5/ 30/03 5/ 29/03 5/ 28/03 5/ 27/03 5/26/03 5/ 25/03 5/ 24/03 5/ 23/03 5/ 22/03 5/ 21/03 5/ 20/03 5/ 19/03 5/ 18/03 5/ 17/03 5/ 16/03 5/ 15/03 5/ 14/03 5/ 13/03 5/ 12/03 5/ 11/03 On May 26th, the child’s mother became ill. Wisconsin Animal Dealer, Primary lesion Mother ill Purchase PD at swap meet Poxvirus on EM, WI DOH notified Dealer ill PD bites child Child ill 6/ 11/03 6/ 10/03 6/9/03 6/8/03 6/7/03 6/6/03 6/5/03 6/4/03 6/3/03 6/2/03 6/1/03 5/ 31/03 5/ 30/03 5/ 29/03 5/ 28/03 5/ 27/03 5/26/03 5/ 25/03 5/ 24/03 5/ 23/03 5/ 22/03 5/ 21/03 5/ 20/03 5/ 19/03 5/ 18/03 5/ 17/03 5/ 16/03 5/ 15/03 5/ 14/03 5/ 13/03 5/ 12/03 5/ 11/03 The Marshfield Clinic grew virus from mother and PD identified as a poxvirus by EM. The WI DOH was notified of illnesses in all parties, initiated traceback on Prairie Dogs and notified CDC. Monkeypox confirmed Executive Poxvirus at CDC Order on EM, by PCR FDA/CDC WI DOH notified Mother ill Purchase PD at swap meet Dealer ill PD bites child Child ill 6/ 11/03 CDC and FDA issued a joint emergency order prohibiting trade and movement of PDs and African rodents. 6/ 10/03 6/9/03 6/8/03 6/7/03 6/6/03 6/5/03 6/4/03 6/3/03 6/2/03 6/1/03 5/ 31/03 5/ 30/03 5/ 29/03 5/ 28/03 5/ 27/03 5/26/03 5/ 25/03 5/ 24/03 5/ 23/03 5/ 22/03 5/ 21/03 5/ 20/03 5/ 19/03 5/ 18/03 5/ 17/03 5/ 16/03 5/ 15/03 5/ 14/03 5/ 13/03 5/ 12/03 5/ 11/03 CDC confirmed monkeypox in samples from mother and PD. 2003 Monkeypox Outbreak Characteristics • 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 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…) Movement of Imported African Rodents to Animal Distributors and Distribution of Prairie Dogs from Point of Infection MMWR July 2003 NJ Rodent Shipment from Accra, Ghana 4/9/03 4/9/03 ? TX 2 GR RS, BTP SS TX 1** 50 Gambian rats (GR) 53 rope squirrels (RS) 2 brush-tailed porcupines (BTP) 4/11/03 47 sun squirrels (SS) 100 striped mice (SM) ~510 dormice (DM) WI Human cases: 17 confirmed 22 probable/ suspect TX 3 42 PDs traced RS, SM DM 14 PDs traced IA† 4/17/03 IL 1§ 4/21/03 TX 5 DM DM 200 prairie dogs (PDs) in existing inventory 1 PDs traced TX 6 11 PDs traced TX 9 4/28/03 TX 7 TX 8 MI DM DM No human cases 4/29/03 5/12/03 TX 10 DM June 2003 lab confirmation: diseased animals derived from shipment SC DM No human cases IL 2 DM 6/1/03 Japan DM MN DM 6/1/03 WI DM Human cases: 7 confirmed 9 probable/ suspect MO Human cases: 2 confirmed 1 PD traced 4/26/03 SS, SM DM IN 24 PDs traced GR, DM GR, DM TX 4 IL‡ Human cases: 8 confirmed 4 probable/ suspect KS Human cases: 1 confirmed Gambian Giant (Pouched) Rat Striped Mouse Rope Squirrel Sun Squirrel Evidence of monkepox infection in laboratory testing Dormouse 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 Thyrotoxicosis • South Dakota, June 1985 • Eight persons aged 29-76 years (5 men) • Symptoms: anxiety, palpitations, dyspnea, weight loss, tachycardia • Signs: elevated T4, low RAIU • Onset: May - June 1985 Background • Cases clustered in two SD towns (near MN) • Interviewed eight patients • No common exposures • Drew blood from patients and family • Tests run 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 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 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 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 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 Salmonellosis • January 1981 call to CDC: – 36 cases Salmonella munchen in Jefferson Co., OH since mid-December 1980 • 26 cases with same serotype in Lansing, MI Descriptive Epidemiology – Age range: 1 month - 76 years – 28% of patients aged 20-29 years – Located in 3 disparate neighborhoods in Jefferson County, OH 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 Pregnant Woman - Key • Interviewed pregnant woman for activities (in which she no longer participated) Pregnant Woman - Key • Interviewed pregnant woman for activities (in which she no longer participated) – Smoking – Drinking alcohol – Smoking marijuana “Smoking” Gun… • Upon further questioning: – At least one member of each casehousehold smoked marijuana • Marijuana from all households in town positive for S. munchen • Biologic plausibility Infection control survey 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 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 All * Small Mixed Equine Large Female 48% 52% 27% 21% 19% < 10 years in practice 26% 27% 24% 24% 24% Owner 58% 54% 78% 66% 72% ≥ 40 hours per week 66% 61% 86% 86% 84% 5% 6% 0.5% 11% 10% 4% 22% 2% 24% 3% 13% 47% 20% 67% 11% Teaching Mobile Only Policy (yes) Preliminary results *weighted population average Infection control practices All * Always wash 53% hands before eat May eat in animal 86% areas May recap 93% needles May re-use needles Preliminary results 32% Small Mixed Equin Larg e e 55% 47% 31% 28% 86% 91% 82% 79% 92% 95% 98% 97% 28% 52% 15% 41% *weighted population average Engage in protective behavior when handling… All* Small Mixed Equine Large Healthy animal 57% 58% 56% 16% 76% Animal wvomiting/diarrhea 25% 24% 40% 52% 54% 20% 16% 37% 18% 62% 44% 27% 44% 26% 47% 34% 16% 14% 69% 54% 4% 5% 1% 1% 0% Animal wneurologic signs Feces Urine Products of parturition Preliminary results *weighted population average When looking at veterinarians by years in practice* < 10 year ≥10 years Always wash hands 53% 53% May eat in treatment area Recap needles Hours per week worked Owner of clinic Bitten in last year Needlestick in last year Cut by instrument 91% 85% 96% 66% 21% 92% 66% 71% 50% 71% 53% 60% 28% 23% Preliminary results *weighted population average 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 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 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 [email protected]