Question

Out of about 1,000 students who ate their lunch at the buffet style dinning hall of a college, 100 had diarrhea about 5 PM on the same day. As an epidemiologist, how and what do you describe the person, time, and place variables/characteristics of this epidemic? What type(s) of clustering would this event have?

do you agree or disagree and why?

In this scenario, the person, time, and place variables would best be described utilizing a case series study. This type of epidemiologic study is most ideal because it analyzes the cause of illness when already given the effects. Age and socioeconomic status best classify the person variables. It can be assumed that the individuals in this study are relatively close in age (early 20’s) since most students begin college after graduating from high school. These individuals also have the same socioeconomic status in terms of education level. The time of occurrence is most likely a point epidemic. Given that the 100 infected students experienced similar symptoms at the same time, they are likely to have contracted the illness during the same time as well. Lastly, this epidemic can be characterized as having localized patterns. Only individuals within this specific dining hall at this specific university were able to contract this disease. Therefore, populations outside of this area are likely to be uninfected. This event has both spatial and temporal clustering. The illness took place within a specific region (college dining hall), and also caused symptoms during the same time frame (5pm the same day of exposure).

Answer 1

The field of descriptive epidemiology describes the occurence of disease based on variables of

1. Person (who is affected) : age, race, sex, socioeconomic status

2. Time ( when and for how much time period disease occured) : point epidemic, cylic fluctuation, secular trends, temporal clustering

3. Place (where the disease took place) : international, localized (spatial clistering), within country, urban- rural

In the above case given the variables of person, place and time can be described as follows:

1. Person:

• Age : As given in the above case report, affected people are college going. Thus they should be of same age group (18-25 yrs)
• Gender: college going students can be both male and female
• Race : college students come from different regions and race
• Socioeconomic status: As they are students they have the same level of education and jobs. So we can say that they have equal socioeconomic status

2. Place : The epidemic of diarrhea break out took place at a specific place and was limited to that place i.e. the dinning hall of college. So this is localized pattern of disease.

3. Time : The epidemic break out at a specific time point i.e. 5PM. This is point epidemic. Point epidemic describes the response of people to a disease at a specific time.

Clustering refers to the closely grouped series of diseased cases with well defined distribution patteren in relation to time, place or both. Clustering in relation to well defined time is called spatial clustering. Clustering in relation to well defined place is called temporal clustering.

In the above case, the epidemic took place at a defined place and time. So it has both spatial and temporal clustering.