Parasitology

Question 1

What are protozoa?

Answer 1

Microscopic single celled organisms (can be free-living or parasitic)

• can multiply and cause serious infection

Question 2

How are protozoa transmitted from humans?

Answer 2

Protozoa living in human intestine transmitted by fecal-oral route
Protozoa living in blood or tissues transmitted by arthropod vector

Question 3

What is a parasitic protozoa and how it it transmitted?

Answer 3

Organisms that lives on/in host and get its food at expense of host and is transmitted by vector

Question 4

What is a free-living protozoa and how are you infected?

Answer 4

Lives in environment e.g. pond, infected by exposure

Question 5

How are types of protozoa classified?

Answer 5

Mode of movement

Question 6

What are the classificiation of protozoa?

Answer 6

Amoeba - use pseudopodiums (projections)
Flagellates
Ciliates
Sporozoa - not motile in adult stage

Question 7

Name medically important protozoa infections?

Answer 7

• copy paste from slide

Question 8

What are helminths?

Answer 8

Large multicellular organisms (worms)

Question 9

What are the three main groups of helminths?

Answer 9

Nematodes (roundworm)
Trematodes (flukes)
Cestapodes (tapeworms)

Question 10

What does number of worms in infection rely on?

Answer 10

Number of eggs inside human, cannot multiply as in adult form in humans

Question 11

What are the categories of medically important nematodes? and examples of each

Answer 11

Soil transmitted helmiths - ascaris lumbricoides

Filarial parasites - loa loa

Question 12

Name a few medically important trematodes?

Answer 12

Schistosoma mansoni

Fasciola hepatica

Question 13

Name a few medically important cestodes?

Answer 13

Taenia saginata

Taenia solium

Question 14

What are ectoparasites?

Answer 14

Blood sucking arthropods that attack/burrow into skin and remain there for long periods of time

Question 15

name a few ectoparasites

Answer 15

ticks, fleas, lice and mites

Question 16

What are the 2 types of ticks?

Answer 16

hard and soft

Question 17

What are the types of hosts for parasites?

Answer 17

Intermediate - host in which larval/asexual stages develop

Definitive - host in which adult and sexual stage occurs

Question 18

What are the types of vectors parasites can have?

Answer 18

Mechanical when no development of parasite in vector

Biological - some stages of parasite life cycle happens in vector

Question 19

What determines parasite infection spread and distribution?

Answer 19

Depends on mode of tranmission

Faeco-oral - access to clean water, household sanitisation
Food - government controls
Complex life cycle of parasite - host is intermidiate or definitive
Education
Urban / rural

Question 20

Why is a parasite life cycle complex?

Answer 20

have diff types of hosts(definitive and intermediate) and vectors (biological and mechanical)

Question 21

What is chagas disease?

Answer 21

Protozoa disease caused by trypansoma cruzi protozoa

Question 22

What is the life cycle of trypansoma cruzi?

Answer 22

Triatomine bug takes blood meal allowing tyrpansoma cruzi to enter through bite wound
It penetrates cells and transforms into AMASTIGOTES
Amastigotes multiply by binary fission in infected cells
Intracellular amastigotes transform into trypomastigoes and bust out cell and enter blood stream and either cycle starts here and enters another cell

Triatomine bug takes blood mean and carries of the parasite for cycle to start again in new person

Question 23

What are the phases of chagas disease?

Answer 23

Acute, chronic intermediate, deteminate chronic disease

Question 24

What happens in the acute phase of chagas disease? + symptoms

Answer 24

Tryposomes in blood
Mild to no symptoms
- Local swelling
- fever
- anorexia

Question 25

What happens in the chronic "intermediate" stage of chagas disease?

Answer 25

Lifelong infection - parasite present at low levels - may not be detected from serum , can useing ECG and X rays

Question 26

What happens in the determinate chronic disease phase of chagas disease?

Answer 26

Seropositive, can detect in blood and effects organs including heart+ digestive system

Question 27

How does Chagas effect the heart?

Answer 27

Parasite infests hearts purkinje fibres in conduction systems causing inflammation and fibrosis damaging to conduction system leading to: - arrythmia - cardiomyopathy - aneurysm at apex - enlarged heart with thin walls - causes heart failure

Question 28

How does Chagas affects the digestive system + symptoms?

Answer 28

Esophagus, rectum, and SIGMOID colon most affected | MEGACOLON - constipation, faecaloma, obstruction, sigmoid volvulus, ulceration

Question 29

What is the pathogenesis of chagas in the diff phases of disease? ie the cytokines and cells involved

Answer 29

Acute - tissue damaged by inflammatory response and antibodies kill parasite activated by innate immune response and Th1 pro-inflammatory cytokines Chronic intermediate - regulatory immune response by IL10 and IL17 Chronic determinate - chronic inflammatory response due to perisistent paraites in muscles and nerve cells - predominantly Th1 cytokines and CD8+ cells

Question 30

What is leishmania?

Answer 30

Parasite disease

Question 31

What is the vector for leishmania?

Answer 31

SAND FLY

Question 32

What is the life cycle of leishmania?

Answer 32

Sand fly has blood meal and transmits promastigote Promastigotes enter macrophages + form amastigotes via asecula reproduction Cell bursts and amastigotes released to further infect via another sand fly or to other cells

Question 33

What are the types of leishmania disease?

Answer 33

Visceral leishmaniasis | Cutaneous leishmaniasis

Question 34

How can leishmania disease be viewed?

Answer 34

Under microscopes inside cells as amastigotes

Question 35

What is the vector for leishmania?

Answer 35

sand fly

Question 36

What are the reservoirs for leishmania?

Answer 36

Dogs (domestic), rodents

Question 37

What are the clinical forms of leishmania disease?

Answer 37

Ulcers, lesions from continuous reactivation

Question 38

What is diffuse leishmania?

Answer 38

Nodules packed with leishmania parasites

Question 39

What is mucocutaneous leishmania?

Answer 39

decomposes + damage of tissue = loss of septum

Question 40

What is the stages + pathogenesis of cutaneous leishmanias?

Answer 40

Acute lesions Latency Relapse

Question 41

How do you know currently have latent cutaenous leishmania?

Answer 41

Balance between Th1 and pro-inflammatoy reponse