Self-Assessment Questions (SAQs) for Study Session 6

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions. 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 6.1 (tests Learning Outcome 6.1)

Which of these statements is false? In each case, explain why it is incorrect.

A  All arthropods have six legs and a body divided into three parts, namely the head, thorax and abdomen.

B  Diarrhoeal diseases can be transmitted to humans by houseflies.

C  Transmission of a disease to a human by a biting insect is called mechanical transmission.

D  Rats can transmit bubonic plague to humans by eating and contaminating stored food, especially grains.

Answer

A is false. Insects have six legs and a body divided into head, thorax and abdomen. Arthropods are a larger grouping that includes insects but also includes many others such as arachnids and crustaceans.

B is true although diarrhoeal diseases can also be transmitted to humans by direct consumption of infected food or contaminated water.

C is false. Transmission by a biting insect is an example of biological transmission.

D is false. Fleas are the vectors of bubonic plague and their natural host is the rat. A person must be bitten by an infected flea to get the disease. Rats will eat stored food but that is not the mechanisms for transmitting bubonic plague.

SAQ 6.2 (tests Learning Outcomes 6.2 and 6.4)

Match the diseases with the respective vector.

Using the following two lists, match each numbered item with the correct letter.

  1. Endemic typhus

  2. Diarrhoea

  3. Malaria

  4. Relapsing fever

    Typhus fever

  5. Rabies

  • a.Anopheles

  • b.Dog

  • c.Fly

  • d.Flea

  • e.Louse

The correct answers are:
  • 1 = d
  • 2 = c
  • 3 = a
  • 4 = e
  • 5 = b

SAQ 6.3 (tests Learning Outcomes 6.2 and 6.3)

Visit five to ten households in your area. Observe and ask what environment and behaviour supports the breeding of vectors. List the commonly found vectors that the members of the household complain of. Prepare a checklist for vector assessment that can be used for field investigation.

Answer

Your answer will depend on the situation in your locality but may include poor personal hygiene (dirty clothing, unwashed body) for lice infestation; unclean floor, unplastered walls and poor ventilation for fleas; stagnant water for mosquitoes; cracks on the wall for bedbugs.

Possible checklist for vector assessment:

Name of vectorBreeding siteNumber of affected households
Housefly
Flea
Louse
Mosquito
Rats

SAQ 6.4 (tests Learning Outcome 6.3)

Visit a place in your locality where there is standing water such as a pond, stagnant water or slowly moving wastewater. Look closely at the water for at least ten minutes and identify the vectors you observe. Use the pictures that are given in this study session to help with identification.

Answer

You may find the larva and pupa stages of Anopheles species in clean standing water; or Culex in dirty water.

SAQ 6.5 (tests Learning Outcomes 6.3 and 6.4)

What specific vector-borne diseases are likely to be found in jails, prisons or army camps? Explain your answer.

Answer

The most likely diseases are typhus fever and relapsing fever, both of which are transmitted by lice. The conditions inside a prison encourage the breeding and spread of lice because the inmates live in close proximity to each other and good personal hygiene may not be possible.

SAQ 6.6 (tests Learning Outcomes 6.3 and 6.4)

Houseflies are commonly found in all domestic situations. Describe the breeding environment of the housefly and name the diseases that are transmitted by flies in your area.

Answer

Fresh dung (cow, ox, donkey, horse, mule), human excreta and decaying vegetables are all good organic matter that supports the breeding of houseflies. Diarrhoeal diseases are carried by flies.

SAQ 6.7 (tests Learning Outcome 6.5)

Imagine that a local householder has a problem with rats and has consulted you for advice. What methods of vector control would you consider recommending?

Answer

The first step in control of rats is to locate their breeding places and clean up any waste or debris that the rats are using for food or shelter. The aim is to starve the rats by removing their access to food sources and clearing any possible places of harbourage. Traps may also be useful. You may also have considered the use of rat poison as long as it is used with care.

SAQ 6.8 (tests Learning Outcome 6.5)

The woreda administrator asks you to prepare a plan of action for vector management. Describe how you would go about it.

Answer

The key steps in your plan of action for vector management should be:

  1. Identifying the type and magnitude of health problems caused by vectors.
  2. Prioritising vectors and identifying their management/control options.
  3. Identifying partners.
  4. Implementing the plan of action.

Summary of Study Session 6