1.   Define the terms-Sampling, sampling unit, sampling frame,& sampling scheme


Ø Sampling: The process of selecting any portion of a population as representative of that population.

Ø Sampling Unit: An element or set of elements considered for selection in some stage of sampling

Ø Sampling Frame: A list of all the sampling units in the population

Ø Sampling Scheme: A method of selecting sampling units from a sampling frame.

2.Define Convenience sampling.

Ø Convenience Sampling: The sample is obtained on convenience basis.  Investigators select the study units that happen to be available at the time of data collection. (Many hospital-based studies use convenience samples).  A major limitation of this approach is that the sample drawn may be quite unrepresentative of the study population

3.Mention types of probability sampling


·        Simple random sampling

·       Systematic Sampling

·       Stratified Sampling

·       Cluster Sampling

·       Multistage Sampling

4.Explain how to get a sample in systemic sampling.


• In systematic sampling, elements in the sample are obtained in a systematic way.

5.Define Epidemiology.


 Epidemiology: The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

6.Definition of HEALTH.


Health: A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity. (World Health Organization)

7. What is a meaning of a disease Determinant.


Disease determinant: A factor which determines the nature or outcome of a disease.

8. Provide an examples of determinant s/factors influencing disease.


·       Age

·       Sex

·       Genetic

·       Ethnicity

·       Iron and folic acid

·       Cholesterol

·       Protozoa  ( e.t.c)

9. Mention four types of factors that play part in causation of a disease


·       Predisposing Factors

·       Enabling Factors

·       Precipitating Factors

·       Reinforcing Factors

10. Four levels of disease prevention in  Epidemiology;


·       Primordial Prevention

·       Primary Prevention

·       Secondary Prevention

·       Tertiary Prevention

11. Define-Mean,mode,& median.


v The mean; is simply the arithmetic average of the data and is calculated by taking the sum of all values in the number set and dividing that total by the number of values in the dataset.

v The median; is the 50th percentile of the values in a dataset and represents the literal middle of the dataset.

v The Mode;  represents the value that is found most frequently in a set of numbers, though it is not often used.

12. Define a variable


Variable: A term for a characteristic that is different in different members of a population or sample, such as height.

13.Mention types of variables.


v Qualitative (categorical) variables

v Quantitative (numerical) variables

14. Explain the difference between discrete and continuous variables


       Discrete variables take only fixed values, in most cases whole numbers, for example:

·       Parity: 0, 1, 2, 3, 4, 5, 6, 10

·       Age last birth day: 5, 19, 45, 90

·       Counts: 1, 2, 3, 4, 5, 9

·       Number of AIDS cases: 100, 10000, 34278.

Continuous variablestake any value within meaningful extremes, for example:

·       Height (cm): 159, 25, 160.35

·       Weight (kg): 71.12, 80.56

·       Exact age like 21 yrs 6 months and 4 days


15. Mention ways you can use to present data


·       Table,

·       Histograms,

·       line diagrams,

·       frequency polygons, and

·       cumulative frequency curves

16.Mention the advantages of a cluster sampling


·       Simple, as no list of units required

·       Less resources required


17.Define Ecology


Ecology: The study of the relationship between organisms and their environments.

18.Define CLIMAX STATE in relation with Ecology.


Climax State - This is the final constant condition of flora and fauna in a specified geographic area

19.What is population density

ANS; Population means all the inhabitants of a particular place, and density refers to the quantity of people or things in a given area or space

20.What is Herd Immunity?

2O.What is Herd Immunity?


Herd immunity is the ability of a community to resist disease. It can occur naturally by exposure to infection or artificially by vaccination.

21.Explain the epidemiological models of disease causation.


Disease does not occur due to a single factor, but due to a number of interrelated factors. 

• These factors can be divided into two categories: 

- Essential/Necessary Factors

-Contributory Factors

• Essential/necessary factors are ‘required ingredients’ for disease to occur.

Ø These are agents of disease such as bacteria and viruses in infectious diseases, and fire, nutrition, radiation or various poisons in non-infectious diseases.

 • Contributory factors are host environment factors that are associated with increased likelihood of disease occurrence.

·       For example: ƒ Host Factors: immunity, sex, age, etc. ƒ Socio-economic factors: poverty, development, etc. ƒ Physical/Environmental Factors: rainfall, temperature, etc. ƒ Biological Factors: presence of vectors, animal reservoirs, etc

22. Explain Natural History of a disease.


Natural History of Disease: Refers to the course of a disease over time, when unaffected by any human intervention like prevention, treatment or rehabilitation

23.Define Pathogenesis


Pathogenesis: The step-by-step origination and development of a disease

24. Mention Host factors Responsible for Pre-pathogenesis.


Host factors include:

·       Age ƒ

·       Sex ƒ

·       Social class ƒ

·       Personality ƒ

·       Genetic factors ƒ

·       Education ƒ

·       Marital status

v Note: a hostis an organism capable of being infected by an agent.

25.Mention Agent factors related to the survival the Micro-organism in external  environment.


These include:

·        Infectivity ƒ

·        Pathogenicity ƒ

·        Virulence ƒ

·        Antigenicity


26.Define Primordial Prevention


Primordial prevention: Preventing agents or risk factors; preventing the interaction between host, agent and environmental factors, so that disease may not occur

27. Define Disease Prevention


Disease Prevention: Inhibiting the development of a disease before it occurs.


28. Define Primary Prevention


Primary prevention: preventing healthy people from becoming ill.

29. Give FOUR examples of Primary prevention


 Examples of primary prevention include:

§  Immunization

§  Wearing shoes to prevent hookworm

§  Adequate intake of proteins and vitamins to prevent malnutrition

§  Use of mosquito nets to prevent malaria

§  Health education and promotion initiatives aimed at fostering positive health behaviors

v ƒ For example, promoting the use of latrines, promoting condom use, etc

30.Mention 5 Components necessary  for disease transmission in Humans


 Transmission of diseases in humans requires the following components:

·       An agent, capable of infecting a human

·        A source (an infected host or reservoir of infection)

·        A portal of exit from the source

·        A suitable means of transmission

·        A portal of entry into a new, susceptible host.

31. Define Agent of a disease.


Agent: the etiological factor which must be present for the disease, disability or pathological state to occur in a susceptible host.

32. Define Infectivity.


Infectivity: The capacity of a micro-organism to enter a susceptible host.

33. Define Pathogenicity.


Pathogenicity: Refers to the capacity of a micro-organism to cause overt disease in the infected host

34. Mention 4 Portals of Exit in the Human Host


Portals of exit in humans:   

·       Respiratory passages 

·        Alimentary canal

·        Openings in the genitor-urinary system

·       Skin lesions

35. Give Examples of Horizontal transmission of adiseases


Examples of horizontal transmission of diseases include:

·       Droplet infection ƒ

·       Faeco-oral route ƒ

·       Genital ƒ

·       Direct skin contact

36. Mention types of vectors


·       Mechanical vectors

·       Biological vectors


37.Mention two broad categories of epidemiological studies


·       Observational Studies

·        Experimental Studies

38. Mention two types of observational study


        There are two types of observational studies: 

§  Descriptive Studies

§  Analytical Studies


39.Mention studies included a Analytical studies


Examples of analytical studies include:

§  Ecological Studies

§  Cross-sectional Studies

§  Cohort Studies

§  Case-Control Studies

40. Mention three methods of hypothesis formulation

ANS; There are three methods of hypothesis formulation

§  Method of Difference

§  Method of Agreement

§  Method of Concomitant Variation

41. Define disease surveillance


    Disease surveillance –Is a systematic collection, analysis, and use of information for the control of a specific disease

42. Mention 2 types of Case-control study designs


Types of Case-Control Study Designs 

      • Retrospective Case-Control Design

      • Prospective Case-Control Design

43. Mention 4 major steps in Case-control study


Major Steps in Case-Control Study

      • Define and select cases

       • Select controls

      • Ascertain exposures

      • Compare exposure in cases and controls by obtaining proportions or odds ratios.

     • Test any differences for statistical significance.

44. Define Screening in epidemiology



Screening:   The examination of asymptomatic people in order to classify them as likely or unlikely to have the disease of interest.

45. Mention 3 Examples of screening test.


  Examples of Screening Tests;

·       Pap smear 

    • Mammogram

    • Clinical breast exam  

    • Blood pressure determination

    • Cholesterol level 

    • Eye examination/vision test  

    • Urinalysis

46. What do you understand by Mass screening?


Mass screening: Is a screening of a whole population.

47. What level of prevention is mass screening?


MASS SCREENING   is a secondary level of prevention.


48. What do you understand by Targeted screening?


Targeted screening: Is a screening of groups with specific exposures.

49. Define sensitivity and specificity of a test.


Ø Specificity: The ability of a test to give a negative finding when the tested person is truly free of the disease under study.

50. What is a sensitivity of a screening test


 Sensitivity: The ability of a test to give a positive finding when the tested person truly has the disease under study

51. Define Endemic Disease


 Endemic Disease is a  diseases which are continuous and/or habitually transmitted in populations throughout the year (such as malaria)

52. Define Epidemic


Epidemic: The occurrence of more cases of a specific disease in a population that is clearly in excess of the expected incidence in a specified period of time.

53. Define Pandemic disease


Pandemic Disease this is expressed when an epidemic spreads to affect many countries globally

54. Mention 3 types of epidemics


Ø Common Source epidemic

Ø Propagated (Progressive) Epidemic

Ø Mixed epidemic

  55. Define propagated (progressive) Epidemic


Propagated epidemics result from transmission of an infectious agent from an infected host to a susceptible one.

56. Mention things that should be done in preparation  for Field Work


• Assemble a team (rapid response team).

• Assemble relevant supplies and equipment (transport media, specimen bottles, information/education/communication (IEC) materials, treatment guidelines & medical supplies, transport, communication means, investigation and surveillance forms, funds, fuel, etc).

 • Alert district authorities

57. Explain how do you Establish Existence of an epidemic


 • Compare observed incidence with expected:

       - No seasonality: compare with incidence from previous weeks/ months,

         - Seasonality: compare incidence from similar periods of earlier years.

• Use action threshold.

58. Integrated diseases surveillance and Response.


Ø Integrated Diseases Surveillance and Response: A strategy proposed and adopted by the World Health Organization/AFRO Regional Assembly in 1998 to strengthen disease surveillance in member countries using an integrated approach.

59. Define standard case definition


Standard Case Definition Is a set of standard criteria for deciding whether a person has a particular disease or other health condition by specifying clinical criteria and limitations on time, place and person.


6o.Define disease control, prevention and eradication


Control of Disease: Reduction of disease prevalence to a level where it is no longer a public health problem.

Prevention of Disease: Any activity which reduces the possibility of occurrence, or the burden of morbidity, disability or mortality of a disease

Eradication of a disease is a process of removing completely disease from occurring in environment.

1.   What differentiates a clinician from an epidemiologist?

2.   There is an outbreak in Mwendakulima, what epidemiological method of study suits the case and gives reasons?

3.   Define Screening/testing of the disease.

4.   Cohort study design.

5.   Case-control study design.

6.   Define the word sampl

7.   Differentiate Statistic and parameter.

8.   What is natural history of the disease?

9.   Explain to the layman so that he can capture the meaning of Epidemiology.

10.                               Mention three importance of biostatistics.

11.                               Define what is qualitative data?

12.                               Define Primary Data.

13.                               Define Secondary Data.

14.                               Define Quantitative Data.

15.                               Mention three epidemiological disease causation models.

16.                               Differentiate Data and information.

17.                               What is Biostatistics?

18.                               What is Data?

19.                               Mention four levels of disease prevention in epidemiology.

20.                               Mention two epidemiological disease causation theories.

21.                               Define HEALTH according to World Health Organization( WHO 1948).

22.                               Determinants of Health and Diseases can be grouped into four groups , name them.

23.                               Mention four Types of screening methods

24.                               Define Climax state.

25.                               What is Food Chain?

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