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Vectors

Vectors. By Sacy Bynoe. What are vectors?. Vectors are small organisms or animals that bring diseases to the body. They act as a reservoir from which pathogen can be transmitted diseases to the host. How do they transmit diseases?. A vector transmit diseases by: 1. Picking up the pathogen

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Vectors

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  1. Vectors By Sacy Bynoe

  2. What are vectors? • Vectors are small organisms or animals that bring diseases to the body. • They act as a reservoir from which pathogen can be transmitted diseases to the host.

  3. How do they transmit diseases? • A vector transmit diseases by: • 1. Picking up the pathogen • 2. Carrying it in their bodies • 3. Injecting it into the host while feeding (mosquitoes) or landing on food (houseflies), which the host then eats.

  4. Mosquito as a vector

  5. The life cycle of a mosquito • The mosquito goes through complete metamorphosis, i.e. it goes through all four stages: • Egg • Larvae • Pupa • Adult

  6. What happens at each stage

  7. Eggs • The eggs are laid one at a time on still water and left to float.

  8. Larva • After about 48 hours, eggs are hatched into larva. • They live in water, and grows siphons for breathing. • They start feeding and growing, shedding their skin as they increase in size.

  9. Pupa • At this stage it does not feed, and it rests. • The larval tissues reorganize to form adult tissues and the adult is formed. • It takes approximately two days for the adult to develop.

  10. The adult/ imago! • After the pupal skin splits and the imago immerges, it rests on the water and allows itself to be dried. • At this stage the vector can transmit diseases.

  11. The cycle

  12. Diseases caused by mosquitoes

  13. Dengue fever • Dengue fever is transmitted by the female aedes aegypti mosquito. • The pathogen is injected in the body when feeding. • Sypmtoms include: • Backaches • Chills • Painful eyes

  14. Malaria • This is transmitted by the anopheles mosquito. • It is caused when the mosquito inject the malaria parasite sporozites in the body, and the parasites travel through the blood stream and affect the body. • Symptoms include: • Headaches • Nausea • Vomiting

  15. Houseflies as a vector

  16. The life cycle of houseflies • Mosquitoes go through complete metamorphosis

  17. What happens at each stage

  18. Eggs • Eggs are laid in decaying material and a female can lay up to 150 eggs.

  19. Larva • Within a day, eggs are hatched into larva/ maggots. • They are legless and white n feed from the surroundings where they hatched

  20. Pupa • Larva develops to pupa after pupating in a dark region. • It develops a hard brown shell which protects it while developing.

  21. Adult • The pupa fully develops legs and wings and immerges as a fly!

  22. Life cycle

  23. Diseases caused by flies

  24. Typhoid fever • This is transmitted by infected flies to the host. • It is caused by salmonella typhi. • Symptoms include: • Loss of apetite • Lethargy • Pain in the body

  25. Cholera • This is caused by a fly transmitting the bacterium vibria cholerae. • Symptoms include: • Excessive thirst • Dry mouth • Sunken eyes

  26. Summary • Vectors transmit pathogenic diseases. • The transmission of these diseases can be limited if the breeding of the vectors are stopped or the destruction of them developing during metamorphosis.

  27. The End

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