Self-Assessment Questions (SAQs) for Study Session 1

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering the questions below. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.

SAQ 1.1 (tests Learning Outcome 1.1)

Consider a disease known as diabetes mellitus, which is characterised by an increase in the blood sugar level. Infectious agents may contribute to the development of the disease in early childhood, but are not the main cause of the disease. Can it be classified as communicable? Explain your reasons.


Diabetes mellitus is not communicable; rather it is non-communicable for the following reasons:

  • The main cause of the disease is not an infectious agent
  • It cannot be transmitted from a person with diabetes mellitus to another person.

SAQ 1.2 (tests Learning Outcome 1.2)

Giardiasis is an endemic communicable disease in Ethiopia. Its infectious agent (Giardia intestinalis) is a single-celled organism bigger than bacteria, but not visible with the naked eye. To which class of infectious agents listed below is it likely to belong? Explain your reasons.

A    Helminths

B    Viruses

C    Protozoa.


C  Protozoa is the correct answer. This group of infectious agents are single-celled organisms, which are bigger than bacteria but not visible with the naked eye.

SAQ 1.3 (tests Learning Outcomes 1.2, 1.3 and 1.4)

Hookworm infection is caused by parasites which are common in Ethiopia. The parasites live in the human intestine and lay eggs which are expelled from the body with the faeces into the soil. The eggs grow into worms in the soil, which penetrate the skin of people walking barefooted. Identify each of the following in this example:

A    The infectious agent

B    The reservoir

C    The mode of transmission

D    The route of exit and the route of entry.


A  The infectious agents are hookworms.

B  Humans are the reservoir for this parasite.

C  The mode of transmission is indirectly by contaminated soil.

D  The route of exit is through the anus with faeces, and the route of entry is through the skin.

SAQ 1.4 (tests Learning Outcome 1.4)

Based on the description in SAQ 1.3, what are the risk factors for hookworm infection?


The risk factors for hookworm infection include walking barefooted and poor environmental hygiene due to expelling faeces into the soil.

First read Abebe’s story and then answer the questions that follow it.

Case study 1.1 Abebe’s story

Typhoid fever is a disease that manifests clinically with high fever and headache. Suppose Abebe is infected with the infectious agent of typhoid fever, but he has no manifestations of the disease. He works in a cafe and among 20 people he served in one day, five got infected, but only three of these developed the disease. Among the three who developed typhoid fever, two recovered and one died.

SAQ 1.5 (tests Learning Outcomes 1.1, 1.2 and 1.6)

From the given information:

  • a.What are the likely modes of transmission?
  • b.Which of the affected persons are active cases and which are carriers?
  • c.Can you group the 20 people who were served in the cafe into the four stages of the natural history of a communicable disease?


  • a.The likely modes of transmission are contaminated food and water served in the café.
  • b.Abebe and two of the five infected persons who did not develop the disease are carriers; whereas the three persons who developed the disease are active cases.
  • c.All the 20 people who Abebe served in the cafe were in the stage of exposure. Only five of these persons were infected and hence were in the stage of infection. Among the five infected, the three who developed typhoid fever were in the stage of infectious disease. And among these, the stage of outcome for two was recovery and for one it was death.

Summary of Study Session 1