Capstone Cases Case A: Hepatitis A Outbreak in the Midwest By Catherine Dentinge
ID: 243476 • Letter: C
Question
Capstone Cases
Case A: Hepatitis A Outbreak in the Midwest
By Catherine Dentinger and Steven T. Fleming
CAPSTONE CASES
We have developed 15 capstone cases for this edition. These large cases are designed to be used by students to review basic concepts from previous chapters and by instructors to teach these basic concepts using a case-study approach to learning. Case A, “Hepatitis A Outbreak in the Midwest,” is based on an actual outbreak in Ohio in 1998. This case reviews the basic concepts of infectious disease and disease transmission. Case B reviews the concepts of descriptive epidemiology but with a focus on car- diovascular diseases. Case C develops the methods of testing for disease in a population, with a focus on colorectal cancer screening. Case D reviews needs assessment using a comprehensive epidemiological approach to evaluating the need for stroke services in Eastern Ontario, Canada. In Case E, the quality of care in seven Boston hospitals is compared using measures employed by the Centers for Medicare and Medicaid Services (CMS) hospital value-based purchasing (VBP) program. Mortality rates, standardization, and risk adjustment in Kentucky is the focus of Case F. Case G examines the expected changes in non-group coverage and morbidity under the Affordable Care Act (ACA), using the state of Wisconsin as a case. Cost-effectiveness analysis of diabetes screening is the topic of Case H. Case I develops in more detail the cross-sectional study design by considering sleep duration and cardiovascular disease. Case J summarizes the methods related to case–control and prospective cohort study design using obesity and endometrial cancer as the focus. Case K reviews randomized clinical trials with a case involving vitamin E, selenium, and prostate cancer. Because most observational studies must deal with bias and confounding, Case L examines these concepts with a focus on whether abortion is a risk factor for breast cancer. The principles of clinical decision making are reviewed in Case M by considering appendicitis in children. Flemington Village (Case N) is a hypothetical retirement community in which the principles of screening and study designs are reviewed. The final capstone case (Case O) focuses on leadership and managerial epidemiology, particularly during a time of hospital crisis.
BACKGROUND
On December 1, 1998, the CDC was notified of 48 cases of hepatitis A in County R (1990 population 126,137) and County L (1990 population 462,361), Midwest State. By comparison, during the first 30 weeks of 1998, an average of seven cases per week (range 3–15) was reported in the entire Midwest State (1990 population 10,847,115). In County R, 28 ill persons with IgM antibody to hepatitis A virus (anti-HAV) were reported to the county health department with onset of symptoms between November 14 and November 27, 1998; 18 (64 percent) of these patients reported eating at one local restaurant (Restaurant A) during their incubation period. However, no ill food handlers at Restaurant A had been reported. In County L, 19 IgM anti-HAV-positive ill per- sons were reported, with dates of symptom onset between November 6 and November 18. The 17 patients interviewed lived in the western part of one city, and 12 (71 percent) reported eating at a local restaurant (Restaurant Y) during their incubation period. No ill food handlers at Restaurant Y had been reported. Counties R and L are separated by a distance of approximately 100 miles; no links between Restaurant A and Restaurant Y had been identified.
Questions
1. Would you call this an epidemic or an outbreak?
2. What are the steps in an outbreak investigation?
3. Hepatitis A is a viral pathogen. What are the broad categories
of diseases that one must consider when investigating a
gastrointestinal disease outbreak?
4. What characteristics can be used to describe infectious agents
(infectivity, pathogenicity, virulence)?
5. What measures of morbidity would you use to estimate infectivity,
pathogenicity, and virulence?
6. What are the different modes of transmission? Describe the
possible routes of transmission.
7. How would you characterize hepatitis A?
Explanation / Answer
It is a outbreak Eating food made by infected person who didnt wash hand after toilet.drinking untreated water . Close contact with infected person. It affects the liver and gastrointestine Symptoms are diarrhea ,stomach pain, tired ,dark yellow color urine, light color stools ,yellow eyes and skin jaundice. After contact with infected person patients exhibit symptoms 2 to 7 weeks