This Unit is about Parasites and how they are spread.


Living things that depend on other living things for food causing harm on them.

Examples of parasites

  • Ticks
  • Fleas
  • Bed bugs
  • Lice
  • Hook worms
  • Tape worms



  • They suck blood from bodies of animals.
  • They live on bodies of animals like cows, sheep, cats, etc.
  • Ticks spread East Coast fever to animals.
  • Ticks spread lyme disease to people.

Why ticks are not regarded as insects

  1. They have two main body parts while insects have 3 main body parts.
  2. They have 8legs (4 pairs) of legs while insects have 6legs (3 pairs).
  3. They breathe through book lungs while insects breathe through spiracles.

Control of ticks

Spraying with insecticides to kill ticks.

Dip animals to kill ticks.

Graze animals in paddocks.

Hand picking.

Bed bugs

They live in dark place, cracks of beds, in mattresses blankets, etc.

They feed of blood of people.

They spread typhus fever to people.

Control of bed bugs

  • Spraying with insecticides to kill bed bugs.
  • Practicing proper sanitation.
  • Washing and ironing beddings before use.


  1. They feed on blood of people.
  2. They spread typhus fever to people.

Control of lice

  • Practice proper personal hygiene.
  • Avoid sharing clothes with people who have lice.
  • Trim and comb hair.


  1. They suck blood from bodies of animals.
  2. They cause itching of the body.
  3. They live on clothes or animal fur.
  4. They spread plague to people.
  5. Plague is caused by bacteria.

Symptoms of plague

  1. Fever
  2. Headache
  3. Chest pains
  4. Muscle pains

Prevention of plague

  1. Spray with insecticides to kill fleas.
  2. Maintain proper sanitation.

Itch mites

  1. They have eight legs so they are not insects.
  2. They spread scabies to people.
  3. They make a person scratch the skin every time.
  4. Scabies affect the skin especially between the fingers and toes.

Spread of scabies

  1. Direct body contact with infected people.
  2. Sharing clothes, basins, bathing sponges with infected people.
  3. Sharing beddings with infected people.

Prevention of scabies

  1. Iron clothes before wearing them.
  2. Wash clothes and keep them clean.
  3. Avoid sharing clothes, towels, beddings with infected people.

Prevention and control of diseases transmitted by the vectors

  • Drain stagnant water around the home to control malaria.
  • Spraying insecticides in our rooms kills most insect vectors.
  • Use mosquito coils and sleep under mosquito nets.
  • Keeping food covered to prevent houseflies and cockroaches from sitting on it.
  • Proper disposal of faeces in latrines.
  • Clear bushes near homes.
  • Use rat traps and rat poison to kill rats in order to control rat plague.
  • Cut hair short and keep it clean, wash clothes and iron them to control lice.
  • Treat/vaccinate dogs and avoid disturbing dogs to control dog bites.


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