Parasitology

Question 1

What is a vector?

Answer 1

An organism that transmits a disease or parasite from one host to another.

Question 2

protozoa infection

Answer 2

Single-celled organisms that can cause diseases
Transmitted by insects

Question 3

Who cause and transmit Malaria?

Answer 3

Plasmodium
mosquitoes transmit plasmodium to human

Question 4

What factors contribute to the prevalence of malaria?

Answer 4

Poverty and climate conditions that favor mosquito populations.

Question 5

What is the life cycle of Plasmodium?

Answer 5

1. Mosquito injects sporozoites into the blood vessels (~100 cells)
2. Sporozoites travel to the liver, stop there for a week (varies depending on species), replicate to 1000 cells
3. Become Merozoites
4. Merozoites invade red blood cells
5. Replicate in RBCs asexually can form a ring structure in RBC (key diagnosis feature under microscope)

This cause problem, the infected RBCs become sticky and stick to blood vessel block the blood, leading to starve for oxygen, brain will stop functioning finally

6. Some Merozoites can convert to Gametocytes which will transmit to mosquito and start another cycle

Question 6

What happens to infected red blood cells (RBCs) in malaria?

Answer 6

Infected RBCs become sticky, adhere to blood vessels, and can block blood flow.

Question 7

True or False: There are vaccines available for malaria.

Answer 7

False

Question 8

What are gametocytes in the context of malaria?

Answer 8

Forms of the parasite that can be transmitted back to mosquitoes.

Question 9

What is the role of mosquitoes in the transmission of malaria?

Answer 9

Mosquitoes inject sporozoites into humans and can receive gametocytes from infected individuals.

Question 10

What is the difference between parasites and bacteria

Answer 10

Parasites are larger in size, and have more complex cellular structures

Parasites are eukaryotes with nucleus and other complex structures.
They can be single cell or multicellular
There is no vaccines for disease caused by parasites

Bacteria are sigle cellular prokaryotes
Have vaccines for many diseases

Question 11

Discovery of malaria

Answer 11

Charles Laveran: find malaria is caused by parasites in blood (see parasites in blood)
Ronald Ross: find malaria is transmit by mosquitoes (see parasites in mosquitoes)
Tu youyou: find treatment (Artemistin 青霉素)

Question 12

What is the name of the Africa sleeping sickness?

Answer 12

African Trypanosomiasis

Question 13

The cause parasite and the vector of African Trypanosomaisis

Answer 13

Caused by Trypanosome Brucei
Transmitted by Tsetse fly

Question 14

The geography of African Trypanosomaisis

Answer 14

Only present in Africa

Question 15

Where did parasites go after got African Trypanosomaisis

Answer 15

Parasites go into the central nerve and then go into the brain, cause confusion and a “coma” state (looks like sleeping), finally become severe encephalitis which lead to death.

Question 16

Trypanosome Brucei Life Cycle

Answer 16

1. Tsetse fly injection to human, Trypanosome Brucei go into bloodstream
2. T. Brucei multiplies by binary diffusion in blood, lymph, and spinal fluid, T. Brucei is relatively large, it will let the organ be overwhelmed with the parasites
3. Another Tsetse fly ingest T. Bruce
4. T. Bruce multiplies in their midgut by binary diffusion
5. T. Bruce transform to a infectious stage and enters the salivary gland and multiplies, wait to go into another host

Question 17

How long & where does Trypanosomes existes? What is their host at that time?

Answer 17

200 million years
Africa and South America
Dinosaurs

Question 18

Which type of Trypanosome is found in Africa and South America?

Answer 18

Africa: T. Brucei
South America: T. Curzi

Question 19

What is the difference between T. Brucei and T. Cruzi

Answer 19

1. T. Cruzi has much larger mitochondria
2. Their vectors are different, T. Brucei transmit by testes fly, T.cruzi transmit by bettle called Triatomine or assassin bug
3. T. Brucei infect the blood stream but the T. Cruzi infect muscle

Question 20

T. Cruzi’s life cycle

Answer 20

1. Traitomine bite on human at night
2. .T.Cruzi go into human heart muscle, colon muscle, and esophagus muscle
3. It transform to amastigote, replicated in the muscle cells
4. Muscle cells finally burst open
5. Amastigote transform to trypomastigote
6. When there is another bite, the trypomastigote will go back to the Traitomine and multiplied in them

Question 21

What disease does T. Cruzi cause?

Answer 21

It causes Chagas disease

Once you got infected, you will carry it for the whole life and the parasite inside the muscle cell will weaken you heart and cause heart attack, most of the people die from heart attack, but it you can live longer, it will cause problems in your intestine.

Question 22

How did this disease become worldwide?

Answer 22

Due to the long symptomatic time, people who carrier those parasites they don’t know they were infected and they travel around world spread the parasites all over the world

Question 23

What cause and what transmit Leishmaniasis?

Answer 23

Caused by leishmania
Transmitted by sandfly

Question 24

What are two forms of Leishmaniasis? And their related symptom, parasites, and treatments?

Answer 24

1.Visceral Leishmaniasis
-cause enlargement of organ
-will die if not treated
-caused by L. Donovanii
-have very good and effective treatment: Ambizome

2.Cutaneous Leishmaniasis
-stay in the skin
-not deadly, usually self-healing
-caused by L. Major
No good treatment

Question 25

What is the problem of the geography of Leishmaniasis?

Answer 25

Some countries are labeled to have this disease but actually there is only few regions in the country have the disease (ex. .Brazil and India)

Question 26

How large is the sandfly?

Answer 26

Half size of mosquito

Question 27

Leishmania Life cycle

Answer 27

1. Sandfly feed on human transfer the **promastigote** to human body 2. Promastigote has flagella, it infect the macrophage s in liver 3. Macrophage engulf them, they transform to **amastigote**, replicate in macrophage and finally burst it open 4. Amastigote convertie back to promastigote wait for next sandfly

Question 28

What is the principle of the drug abizome? What is the advantage of this drug?

Answer 28

It go into macrophage, set on tope of the amastigote, melt its membrane This happens so fast (treat in the afternoon, cure at night), the cell don’t have time to develop there resistance

Question 29

What molecule does amastigote has on its surface? Human?

Answer 29

Amastigote: ergosterol Human: cholesterol

Question 30

Post kalaazar dermal leishmaniasis (PKDL)

Answer 30

10-25% of people who got treatment for Visceral infection has these white patches contain the parasites on their skin, unable to confirm PKLD as major reservoir for transmission

Question 31

What are the disadvantages of field study?

Answer 31

The sample size sometimes are small And you can’t repeat your study

Question 32

Usually parasites have two stages: i and d

Answer 32

I: infective stage (in vector) D: diagnostic stage (in human)

Question 33

Helminth infection transmitted type

Answer 33

1. Soil transmitted Ascaris Trichuris Hookworm 2. Insect transmitted Lymphatic Filariasis Onchocerciasis 3. Snail transmitted Schistosomiasis

Question 34

Morphology of 3 major STHs

Answer 34

1. Ascaris 20 cm, 1 year, 20,000 eggs/day 2. Trichuris 5 cm, 2 years, 5000 eggs/day 3. Hookworm 15 mm, 5 years, 10,000 eggs/day

Question 35

Transmitted method and living space of the 3 STHs

Answer 35

1. Ascaris and Trichuris ingesting eggs 2. Hookworm Larvae All their adult worms live in intestine (gastrointestinal tract), the adult didn’t replicate in the intestine, but they mate and produce eggs and transmit through feces Human are their only host

Question 36

Major symptoms of STHs

Answer 36

Children growth: Malnutrition, growth stunting, cognitive and learning defects Many suppress immune response to other infections

Question 37

Ascaris life cycle

Answer 37

1. Human ingest eggs 2. Eggs grow to larvae, the larvae go through the big and small intestine and then go to the lung 3. Finally go back to the digestive system stay in small intestine

Question 38

Hookworm life cycle

Answer 38

1. Larvae infect people through skin 2. Go through lung and finally stay in intestine 3. Adults mate in the small intestine, produce eggs that released to the environment by feces 4. Grow to rhabditiform larvae 5. Grow to filariform larvae (can infect people through skin)

Question 39

Diagnosis of STH infection

Answer 39

The intensity of infection is measured by the number of eggs/g of feces Determine under microscope

Question 40

Treatment of STH infection

Answer 40

**Goal**: remove all the adults from the intestine **Common drugs**: benzimidazoles and Ivermectin **Principle**: paralyze the adult parasite **Problem**: does not kill eggs

Question 41

elephantiasis: disease name, caused by, transmitted by?

Answer 41

Lymphatic filariasis Caused by Wuchereria Bancroft Transmitted by mosquito

Question 42

Wuchereria Bancroft life cycle

Answer 42

1. Mosquito transmit larvae (L3) to human 2. Adult worm in lymphatic block flow of lymphatic fluid, cause accumulation of lympatic fluid 3. Adult worms produce **Microfilaria** that migrate to lymph and blood canals 4. Microfilaria can be taken by mosquitoes and they develop to L1 larvae in mosquito and grow to L3 larvae

Question 43

Riverblindness: disease name? Caused by? Transmitted by? What cause blind?

Answer 43

Onchocerciasis Caused by Onchocorca Volvulus Transmitted by blackflies Microfilaria accumulate in the eye causing blindness

Question 44

Hypothesis about helminth infection and autoimmune disease

Answer 44

It is hypothesized that helminth infection can reduce auto-immune disease, the infection might suppress the immune system, reduce the overall inflammation associated with autoimmune disease.