BASIC SCIENCE E-NOTE
TOPIC: DISEASE VECTORS
1. Meaning of Disease Vectors
A disease vector is a living organism, usually an insect or animal, that carries and spreads germs from one person or animal to another, causing diseases.
👉 Disease vectors do not usually cause the disease by themselves, but they transmit the germs.
2. Examples of Disease Vectors and the Diseases They Transmit
| Disease Vector | Disease Transmitted |
|---|---|
| Anopheles mosquito | Malaria |
| Aedes mosquito | Yellow fever |
| Housefly | Cholera, Typhoid |
| Tsetse fly | Sleeping sickness |
| Rat | Lassa fever |
| Flea | Plague |
3. Life Cycle of the Anopheles Mosquito
The Anopheles mosquito has four stages in its life cycle:
Egg – Eggs are laid on stagnant water.
Larva – The larva lives in water and feeds on small organisms.
Pupa – This is the resting stage; it still lives in water.
Adult mosquito – The adult mosquito flies and bites humans.
⚠️ Only the female Anopheles mosquito transmits malaria.
4. Transmission of Some Vector-Borne Diseases
Malaria: Spread when an infected female Anopheles mosquito bites a healthy person.
Cholera: Spread when houseflies carry germs from dirty places to food and water.
Sleeping sickness: Transmitted through the bite of an infected tsetse fly.
Yellow fever: Spread by the bite of an infected Aedes mosquito.
5. Methods of Controlling Disease Vectors
Disease vectors can be controlled by:
Clearing bushes around houses
Draining stagnant water
Using insecticide-treated mosquito nets
Proper disposal of refuse
Spraying insecticides
Keeping food covered
Maintaining good environmental sanitation
6. Importance of Controlling Disease Vectors
Controlling disease vectors is important because it:
Prevents the spread of diseases
Reduces sickness and death
Saves money spent on treatment
Promotes good health
Keeps the environment clean and safe
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