Epidemiology module of practical skills for mbbs student

EXERCISE

After a New Years Day breakfast of the 22 members (of whom 12 are women) of the Town Council at Restaurant X, a number of the attendees became ill with fever, nausea, vomiting, headaches, abdominal cramps, and diarrhea. Some developed jaundice, and complained of dark colored urine. After interviews with 15 council members, the following line listing was created.           Foods Eaten ID AGE SEX ILL ILLNESS ONSET Eggs & Bacon Pan Cakes Coffee Milk Cup Cakes 1 38 M Y 1/23 N N N Y Y 2 35 M Y 1/24 Y Y N Y ? 4 35 F Y 1/26 N Y Y Y Y 7 68 F Y 2/2 Y Y Y Y N 8 58 M Y 2/2 Y Y Y N Y 9 53 M Y 2/4 N Y Y N Y 11 57 M Y 2/6 N Y N Y Y 12 59 F Y 2/7 N Y Y N Y 14 33 F N   Y Y Y Y N 3 41 M N   N Y N N N 5 43 F N   Y N ? Y Y 6 61 M N   N Y Y Y ? 10 38 F N   N Y Y Y N 13 62 F N   Y Y Y N ? 15 29 M N   ? Y Y Y N

1.	In making the decision of whether this is an epidemic/outbreak the key factor is
		duration of time between exposure and illness
		frequency of illness relative to the endemic level
		number of people involved
		severity of illness
		whether the illness was infectious

2.	The best estimate of the attack rate per hundred for women is
		14 (3/22*100)
		32 (7/22*100)
		25 (3/12*100)
		38 (3/8*100)
		67 (8/12*100)

3.	What is the most likely infected food?
		eggs & bacon
		pan cakes
		Coffee
		Milk
		cup cakes

Two food items are often eaten together (for example, bread and butter) and one item is contaminated with an agent that causes illness and the other is not.

4.	After the determination of attack rates for individuals who consumed and did not consume each item:
		the contaminated item will show a high relative risk but the uncontaminated one will not.
		the uncontaminated item will show a high relative risk but the contaminated one will not.
		both items will show high relative risks.
		neither item will show a high relative risk.

5.	The uncontaminated item is called:
		an effect modifier
		a confounder
		a causal factor
		a negative correlate

Attack rates were determined for the following four groups of individuals: Group A - consumed item 1 and item 2 Group B - consumed item 1 but not item 2 Group C - consumed item 2 but not item 1 Group D - consumed neither item 1 nor item 2

6.	If item 2 is the contaminated item, attack rates will be highest in Groups:
		A and B
		B and C
		C and D
		A and D
		A and C

7.	The attack rate, as determined from a sudden outbreak of disease, is:
		an incidence rate
		a prevalence rate
		an attributable risk
		a relative risk

8.	An age-adjusted mortality rate for a given population will be lower than the crude mortality rate when that population has
		a good health care system.
		more efficient methods for handling death certificates.
		more elderly people than the standard population.
		less elderly people than the standard population.

9.	The case fatality rate for a disease could be high for all of the following reasons except
		no efficacious treatment for the disease has been discovered.
		methods for preventing the disease have not been developed.
		detection of the disease is difficult during the stage when it is treatable.
		the disease moves rapidly to a highly lethal stage.

10.	The cause-specific mortality rate for a disease will be high when
		the prevalence rate and the case fatality rate are both high
		the prevalence rate is high but the case fatality rate is low
		the prevalence rate is low but the case fatality rate is high
		the prevalence rate and the case fatality rate are both low

11.	Public health initiatives are concerned with disease prevention and treatment. A public health program which is effective in reducing the probability of acquiring a certain disease for all members of the population should
		decrease both the incidence rate and the prevalence rate of the disease.
		decrease the incidence rate but increase the prevalence rate of the disease.
		not change the incidence rate but decrease the prevalence rate of the disease.
		not change the incidence rate but increase the prevalence rate of the disease.
		not change either the incidence rate or the prevalence rate of the disease.

12.	A public health program which effectively provides treatment that prolongs the lives of those in the population with a certain disease should
		decrease both the incidence rate and the prevalence rate of the disease.
		decrease the incidence rate but increase the prevalence rate of the disease.
		not change the incidence rate but decrease the prevalence rate of the disease.
		not change the incidence rate but increase the prevalence rate of the disease.
		not change either the incidence rate or the prevalence rate of the disease.

The incidence of a certain disease is 6 per 100,000 per year for factory workers exposed to lead dust and 2 per 100,000 per year for similar workers not exposed to lead dust.

13.	The relative risk of this disease for those with lead dust exposure is
		0.33
		2
		3
		4
		6

14.	According to the attributable risk, the number of cases of the disease which could be prevented per year for every 100, 000 workers with lead dust exposure is
		0.33
		2
		3
		4
		6

15.	In the investigation of a sudden outbreak of food born disease, potential sources can be identified by the discovery of items with:
		high relative risks
		high attributable risks
		either of the above
		neither of the above