Description

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Disease Outbreak Following Charity Luncheon

On Friday, August 10, 2019, a private physician telephoned the Philadelphia City Health Department to report that on the day before and the morning of her call, she had seen several women with acute sore throats. The illnesses were characterized by acute onset with chills, fever, general malaise, and sore throat. Physical examination revealed inflamed throat with some exudation, cervical adenitis, and temperature between 102- and 104-degrees Fahrenheit.

Question I: What additional information would you request from the physician at this point and why?

The Health Department undertook an immediate investigation. The health officer who made the first home visits verified the original report, and obtained information that this was an outbreak of major proportions.

It was determined (from histories taken by the physician and from personal interview with the reported cases) that all of the women had attended a luncheon on August 8. The luncheon had been a fund-raising effort and was an annual affair for an organization consisting of 96 women. Between 800 and 900 women had attended the luncheon.

The members of the organization had done most of the work involved in procuring and preparing the luncheon food. A commercial caterer and restaurateur had voluntarily assisted in the preparation of the food. The complete menu, which was served cafeteria style, was as follows: egg salad, tuna fish salad, chicken salad, spinach salad with mushrooms, rolls, watermelon, ice cream, coffee, and cookies.

A questionnaire was prepared by the Health Department and distributed one week after the luncheon to all the people known to have attended the luncheon.

• Question II: What items of information would you request on this questionnaire? List at least 10.

The attached table is an abstract of the questionnaire which was returned by 85 of the 96 members. Only 67 of the luncheon guests (non-members) returned the questionnaire. Their responses are not tabulated.

• Question III: What was the attack rate among members who attended the luncheon? (To determine this, it is necessary to define a case and to decide on what population to use as a denominator?
•  Question IV: tabulate the onset by appropriate time periods and draw the epidemic curve. What does this tell you about the outbreak, its etiology, or mode of transmission?
•  Question V: What food, if any is likely to have acted as a vehicle for the agent. Support your conclusions by demonstrating the association between consumption of the food and occurrence of the illness.