Nokea
A case definition during an outbreak investigation should specify:
- A. Clinical features
- B. Time
- C. Place
- D. Person
Correct Answer: A
Rationale: A good case definition includes clinical criteria and details on time, place, and person to ensure consistent identification of cases.
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PNMR refers to:
- A. post Neonatal mortality rate
- B. post natal mortality rate
- C. perinatal mortality rate
- D. prenatal mortality rate
Correct Answer: A
Rationale: Post-neonatal mortality rate refers to deaths occurring between 28 days and one year of age.
The fraction 50 / 54 is a/an:
- A. Attack rate
- B. Food-specific attack rate
- C. Incidence proportion
- D. Proportion
Correct Answer: B
Rationale: This fraction focuses on illness among those exposed to wedding cake.
A local health department epidemiologist investigated an outbreak of gastrointestinal illness thought to be associated with a college cafeteria. There were many complaints about the quality of the cafeteria's offerings, and it appeared that the students' worst expectations were confirmed when several students visited the college's infirmary during the middle of the night and the following day complaining of nausea, diarrhea, fever, vomiting, and cramps. The health department's investigation revealed that 24 students had eaten in the cafeteria immediately before the outbreak. The times between eating in the cafeteria and the development of active symptoms ranged from 20 to 36 hours. A list of foods eaten, the number of persons eating the foods, and tabulations of illness are presented in Appendix 12. Fill in the attack rates where indicated. On the basis of your calculations, answer the following questions: What food or foods would you suspect caused the problem?
- A. Chicken salad
- B. Potato salad
- C. Both A and B
- D. Neither A nor B
Correct Answer: C
Rationale: High attack rates for both chicken and potato salads suggest they were contaminated.
For collection of hazardous waste, color of bin is
- A. black
- B. yellow
- C. red
- D. green
Correct Answer: B
Rationale: Yellow bins are used for the collection of hazardous waste, as per waste management guidelines.
Two automated blood cell counters are tested twice using a prepared suspension of leukocytes containing 8,000 cells/mm3. The cell counts by device A are 8,400 cells/mm3 the first time and 8,350 cells/mm3 the second. Device B's counts are 8,200 and 7,850 cells/mm3, respectively. Which device(A or B) gives leukocyte counts with greater validity?
- A. Device A
- B. Device B
- C. Both devices have equal validity
- D. Neither device is valid
Correct Answer: A
Rationale: Validity refers to how close the measurements are to the true value (8,000 cells/mm3). Device A's measurements (8,400 and 8,350) are closer to the true value than Device B's (8,200 and 7,850).