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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 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 • 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.
The life cycle of a mosquito • The mosquito goes through complete metamorphosis, i.e. it goes through all four stages: • Egg • Larvae • Pupa • Adult
Eggs • The eggs are laid one at a time on still water and left to float.
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.
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.
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.
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
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
The life cycle of houseflies • Mosquitoes go through complete metamorphosis
Eggs • Eggs are laid in decaying material and a female can lay up to 150 eggs.
Larva • Within a day, eggs are hatched into larva/ maggots. • They are legless and white n feed from the surroundings where they hatched
Pupa • Larva develops to pupa after pupating in a dark region. • It develops a hard brown shell which protects it while developing.
Adult • The pupa fully develops legs and wings and immerges as a fly!
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
Cholera • This is caused by a fly transmitting the bacterium vibria cholerae. • Symptoms include: • Excessive thirst • Dry mouth • Sunken eyes
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.
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