Question 3
The diagram below illustrates a vector. Study it and answer questions3(a) to3(c).
(a) Name two:
(i) pathogens; [2 marks]
(ii) diseases, that could be transmitted by the vector. [2 marks]
(b) Mention two methods of controlling the vector [2 marks]
(c) State in sequence, the stages in the life cycle of the vector. [4 marks]
Observation
This question was attempted by majority of the candidates and their performance was poor. Many candidates had problems understanding the difference between pathogens and diseases as required in Question 3(a)(i) and (ii). Similarly, sequential stages in the life cycle of the vector was also not properly answered.
The expected answers are as follow:
3(a)(i) Pathogens that could be transmitted by the vector
- Bacteria
- Virus
- Worms/helminths
- Protozoa
- Fungi
(ii) Diseases that could be transmitted by the vector
- Typhoid fever
- Poliomyelitis
- Cholera
- Dysentary
(b) Measures of controlling the vector
- fumigation / use of insecticides/chemical
- use of net / barrier method
- having good food hygiene practice
- maintaining a clean environment
(c) Stages of life cycle of the vector
Egg -> Larva -> Pupa -> Adult/Imago