Question 4
The diagram below illustrates a worm infestation in humans. Study it and answer questions 4(a) and 4(b).
(a) (i) Name the type of worm illustrated in the diagram. [1 mark]
(ii) Mention the intermediate host of the worm. [1 mark]
(iii) State the two sources through which humans could be infested with the worm.
[2 marks]
(iv) State two observable features of the infected part. [2 marks]
(b) State four ways of preventing the worm infestation in humans. [4 marks]
Observation
Many candidates attempted this question but their performances were poor. Many candidates could not identify the type of worm illustrated as required in 4(a)(i) but instead were naming tapeworm and ringworm. Poor answers to other subsections depended on the wrong identification earlier given.
The expected answers are as follow:
4(a)(i) Type of worm illustrated
- Guinea worm/dracunculus
(ii) Intermediate host of the worm
- Cyclops/water flea/copepod
(iii) Sources in which human could be infected with the worm
- drinking contaminated water
- Wadding in contaminated water
(iv) Observable features of the infected parts
- Threadlike structure appear on the broken skin/sore
- Exposed sore /patches on the leg/blisters/wound
- Swollen foot
(b) Ways of preventing worm infestation
- Drink clean water/ provision of potable water
- Destroy intermediate hosts
- Avoid bathing /wading in rivers/streams
- Patients sores and worm should be handled by medical officer /expert only