Outbreak Investigations Matthew Cartter, MD, MPH Connecticut Department of Public Health August 24, 2016

Why investigate outbreaks? To take immediate action to protect people To learn how to prevent similar occurrences

Outbreak/Epidemic Occurrence of more cases of disease than expected In a given area or among a specific group of people Over particular period of time Outbreak is often the preferred word, as it may escape sensationalism associated with the word epidemic

How do we detect outbreaks? Review of routinely collected or surveillance data The astute clinician! Reports from patients or members of the community Media stories

Conn. Agencies Regs. §19a-36-A6 Conn. Agencies Regs. §19a-36-A6. Investigation and control of reportable disease and outbreaks by the department The department, in cooperation with the local director of health, in the investigation and control of reportable disease shall make or cause to be made such investigation as it deems necessary and shall secure all such data as may assist it in establishing adequate control measures. In order to investigate and control any apparent outbreak or unusual occurrence of reportable disease, the department shall institute such special disease surveillance, follow-up reports and control measures as it deems necessary. (Effective October 25, 1989.)

Epidemiologic Investigation Environmental Investigation Laboratory Investigation New, reemerging or drug resistant infections whose incidence in humans has increased within the past two decades or whose incidence threatens to increase in the near future. Institute of Medicine Report, 1992

If cases are continuing to occur... Goal: prevent additional cases Objective: Assess extent of outbreak and size and characteristics of population at risk Design and implement appropriate control measures

If outbreak appears to be almost over... Goal: prevent outbreaks in the future Objective: Identify contributing factors Design and implement measures that would prevent similar outbreaks

Rabid Terrestrial Animals Connecticut, 1991-2014 Wild Animals Raccoon 5192 (76%) Skunk 1454 (21%) Fox 105 Woodchuck 75 Deer 6 Coyote 6 Bobcat 5 Otter 1 Opossum 1 6845 Domestic Animals Cat 140 (72%) Cattle 23 (12%) Dog 9 Horse 9 Goat 4 Sheep 5 Rabbit 2 Donkey 1 Ferret 1 194

E. coli O157 Bacteria, can live in gastrointestinal tract of healthy cattle, goats, and sheep People can get infected through Contaminated food or drink Contact with infected people Contact with infected animals or their environment

E. coli O157 Exposure to very small number of bacteria can cause illness Can survive a long time in the environment (>42 weeks)* Takes between 1-10 days for symptoms to appear Symptoms include diarrhea (often bloody), abdominal cramps, and vomiting 5–10% develop kidney complications or failure (hemolytic uremic syndrome) Children most vulnerable * Varma, 2003. JAMA.

Outbreak Detection Involved March 24, 2016 – CT Department of Public Health (DPH) identified cluster of seven cases of E. coli O157 infections Six (86%) reported visiting same goat farm prior to illness Joint multi-agency investigation CT Department of Public Health CT Department of Agriculture Local health department Centers for Disease Control and Prevention

Investigation Goals Determine scope of outbreak How large of a problem? How severe are the illnesses? Determine potential causes of infection How did people get sick? Institute control measures to prevent more illnesses Develop recommendations to prevent similar outbreaks in future

Investigation Methods Epidemiologic Interview cases by telephone to collect illness and exposure information Environmental Collect environmental and animal samples at farm Assess facility using NASPHV* guidance Laboratory Conduct testing of human, animal, and environmental samples Compare “genetic relatedness” of bacteria found in human, animal, and environmental samples * National Association of State Public Health Veterinarians, 2013 Compendium of Measures to Prevent Disease Associated with Animals in Public Settings

Epidemiologic Investigation 50 confirmed cases linked to the outbreak Age range: 10 months – 50 years Median age: 5 years 11 (22%) cases hospitalized 3 (6%) cases diagnosed with HUS No deaths

Outbreak Curve

Laboratory Investigation 61 environmental samples tested 28 (46%) positive for E. coli 17 samples from goats tested 16 (94%) positive for E. coli Environmental, goat, and human samples shared similar “genetic fingerprints”

Environmental Investigation Farm hosted events allowing public interaction with goats starting March 5, 2016 Estimated 1,500 visitors between March 5 – March 24, 2016 No handwashing facilities available at farm No signage encouraging use of hand sanitizer No educational materials to inform visitors about potential risks of disease Farm allowed direct contact with animals and soiled bedding

Conclusions Investigation highlighted importance of implementing infection prevention measures Lack of adequate hand washing stations and education materials might have contributed to increased risk of infection to visitors

Recommendations Hands should always be washed with soap and clean running water and dried with clean towels Immediately upon exiting areas containing animals After removing soiled clothing or shoes Before eating and drinking Standard procedures for cleaning, disinfection, and facility design should be adopted to minimize risk Restricting young children (<5 years) access to ruminants should be considered to minimize risk to this vulnerable population