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This article discusses the investigation of a foodborne illness outbreak caused by E. coli O157:H7 and the necessary steps to manage the outbreak and protect public health.
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Foodborne Illness and the Public Health Nurse Bureau of Epidemiology Sally A. Bidol, MPH Mark A. Schmidt, MPH Office of Public Health Preparedness Susan L. Shiflett Michigan Department of Community Health
Laboratory Report To: Local Health DepartmentFrom: HighTECH Labs, Inc • Patient: Doe, Thomas • DOB: 12/03/93 • Address: 300 Any Street, Anytown, Michigan • Result: Presumptive E. coli O157:H7
What would you do?What information will you need to collect?
Information Collected • Onset: Sunday, 5/30 • Bloody diarrhea, fever • No travel history • Municipal water • Not aware of any ill contacts • Mother shops at Grocery Store A • Boy Scout trip to petting zoo
Day 1 Dinner Breakfast Snack Lunch
Day 2 Breakfast Lunch Dinner Snack
Day 3 Lunch Breakfast Snack Dinner
What are the most likely causes of infection? • Food history • Pet • Other exposures
What is the major limitation of the data collected? • Incubation of E. coli O157:H7: • Median 2 to 4 days • Up to 8 days
Laboratory Report To: Local Health Department From: HighTECH Labs, Inc • Presumptive Positive E. coli O157:H7 • 2 Children • 9 y/o attends same school as Thomas Doe • 5 y/o attends day care • 1 Teenager • Works as a food handler at The Healthy Deli • 1 Adult
School Nurse Reports • June 1 – 4, 30 children absent • Typically 5 absent • Most gave reason as “Stomach Flu”
Group Questions • Is it time to activate your outbreak team? • If no, what additional information needs to be collected before you activate the team • How would you go about: • Verifying the diagnosis • Searching for additional cases • Determining if cases are associated • What is your initial hypothesis?
Answers • Is it time to activate your outbreak team? • Yes • Verify the diagnosis • Contact students, ask about symptoms and clinical samples
Answers • Search for additional cases • Ask cases for others experiencing symptoms • Contact medical facilities • Contact EH to check for unconfirmed illness reports • Contact suspect facilities (EH) to ask about complaints • Determine if cases are associated • Person, Place, and Time
More Patient Information • Confirmatory reports from MDCH indicated that 4 patients are positive for E. coli O157:H7 and produce STX I and STX II. PFGE is performed and all isolates are identical. • 2 children on basketball team • Teenager is youth coach of team • Adult is parent of basketball player
More Patient Information • One patient is positive for E. coli O26:NM • 1 child • Not associated with basketball team
E. coli Serotyping • O = Somatic antigen in cell wall • H= Flagellar antigens in the flagellar structure • NM = non-motile, has lost the flagella • Common serotypes include O157:H7
E. coli Toxin Testing • Shiga-like toxin I and II (STX I, STX II) • More important than serotyping • Presence of STX causes illness • Cytotoxic effect, inflammation of intestinal wall leading to death of cells • Results in: • Hemorrhagic colitis • Hemolytic Uremic Syndrome (HUS) • Thrombotic Thrombocytopenic Purpura (TTP) Website of Dr. Brett Finlay Dept. of Microbiology and Immunology Dept. of Biochemistry and Mol. Biology University of British Columbia
E. coli O157:H7 DNA Fingerprinting • Pulsed-field gel electrophoresis (PFGE) • PulseNET
What does this mean? Website of Dr. Brett Finlay Dept. of Microbiology and Immunology Dept. of Biochemistry and Mol. Biology University of British Columbia
Does this change the direction of your investigation? Lab Testing Results
E. coli O157:H7 May - June 2003 (N=28)
Summary of Outbreak • Implicated meal--Steak House Buffet 5/27 • All confirmed E. coli O157:H7 cases consumed fruit from the salad bar • Basketball team ate from the salad bar
Loosely Based on Milwaukee Sizzler Restaurant Outbreak of 2000 • 736 cases, 63 culture confirmed • 18 hospitalizations, 5 cases HUS, 1 fatality • Sirloin tri-tips • Meat ground within 1 foot of fruit and vegetable preparation table.
Management of Food Handlers • Michigan Food Law of 2000 • Regulates all food establishments in Michigan • Provides essential powers, duties, penalties • Adoption of FDA Food Code (model)
Exclusions and Restrictions - Definitions • Big 4 • Salmonella Typhi • Shigella spp. • E. coli O157:H7 • Hepatitis A virus (HAV) • High infectivity • Severe medical consequences • High risk conditions • Caused, or exposed to, a confirmed Big 4 outbreak since person- • consumed implicated food, or • consumed food prepared by infected person, or • consumed food prepared by suspected shedder • Lives with someone diagnosed with Big 4 • Lives with someone who attended/worked at a confirmed Big 4 outbreak
Exclusions and Restrictions ILL Employee Serving General Population Diagnosed with Big 4 GI symptoms Asymptomatic & positive stool Persistent sneezing, coughing or runny nose Jaundice within 7 days Exposed lesion, boil or wound Jaundice > 7 days Exclude Restrict
Child Care CenterAttendance • E. coli O157 illness • spread is a major concern • Infected child or care giver should be excluded until: • Diarrhea resolves • 2 negative stool cultures • Early involvement of local health authorities can prevent further disease
Points to Ponder: Conducting an Investigation • Remember normal background activity • Teamwork between nursing and EH essential • What information is pertinent in an investigation? • How do you interpret the laboratory results? • Don’t forget your epi tools
Got Food Poisoning? Welcome to the Foodborne Outbreak Early Detection System (FOEDS) Forum Web users share and compare info RUsick2 FORUM
WWW.RUSick2.msu.edu • Forum for people with suspected foodborne disease to share and compare their pre-illness food history and other factors. Objective: Did they eat the same food items? Identify common source outbreaks. • Being pilot tested in Greater Lansing Area. • “Delivers” foodborne disease reports to the LHD
RUsick2 Contact Information (www.RUsick2.msu.edu) : Holly Wethington165 Food Safety & Toxicology BldgMichigan State UniversityEast Lansing, MI 48824P: 517.432.7181 (#128)F: 517.432.2310Email: ffmod@cvm.msu.edu