Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Medical microbiology > Parasitology > Flashcards

Parasitology Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards USMLE® Step 1 flashcards
1
Q

What is a parasite?

A

An organism that lives on or in a host organism and gets its food from or at the expense of its host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the different types of hosts for parasites?

A
  1. Intermediate – host in which larval or asexual stages develop
  2. Definitive – host in which adult or sexual stage occurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When are vectors mechanical?

A

○ Mechanical when no development of parasite in vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When are vectors biological?

A

○ Biological when some stages of life cycle occur within the vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 3 classes of parasites?

A
  1. Protozoa
  2. Helminths
  3. Ectoparasites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are protozoa?

A

• Microscopic, single celled organisms that can be free-living or parasitic in nature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are protozoa able to do in humans??

A

• Able to multiply in humans allowing serious infection to develop from single organism
§Not all parasites can multiply in humans but protozoa can

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the ways protozoa can be transmitted?

A

○ Protozoa living in the human intestine can be transmitted by the fecal-oral route
○ Protozoa living in blood or tissues are transmitted by an arthropod vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are protozoa classified by and what are they?

A

• Protozoa are classified by modes of movement
○ Amoeba e.g. Entamoeba
§ Has pseudopodia and moves around by pushing them out
○ Flagellates e.g. Giarda, Leishmania
○ Ciliates e.g. Balantidium
○ Sprozoa – organisms whose adult stage is not motile e.g. plasmodium, cryptosporidium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does entamoeba histolytica cause?

A

○ Causes amoebic dysentery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does a loss of epithelia due to entamoeba histolytica cause?

A

○ Loss of epithelia so causes ulcer formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does giardia lamblia cause?

A

○ Cause diarrhoea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens to the villi of the small intestine due to giardia lamblia?

A

○ Blunting of villi in small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does trichomonas vaginalis cause?

A

causes vaginal discharge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is toxoplasma gondii an infection from?

A

○ Infection from cat faeces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is cryptosporidium a common cause of?

A

○ Common cause of epidemic diarrhoea worldwide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is cryptosporidium a major cause of?

A

○ Major cause of moderate-severe diarrhoea in developing countries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What can cryptosporidium do to growth?

A

Can cause growth stunting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are soil transmitted helminths?

A

○ Ascaris lumbricoides
○ Trichuris trichiura
○ Hookworm spp
○ Enterobius vermicularis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are filarial parasites?

A 
○ Wuchereria bancrofti
○ Loa loa
○ Onchocerca volvulus
○ Onchocerca volvulus 
○ Dracanculus medinensis
21
Q

Medically important helminths(Trematodes)

A

○ Schistosoma mansoni/haematobium/japonicum
○ Clonorchis sinensis
○ Fasciola hepatica
○ Paragonimus spp.

22
Q

Medically important helminths(Cestodes)

A

○Taenia saginata
○Taenia solium
○Echinococcus

23
Q

What are ectoparasites?

A

• Blood-sucking arthropods such as ticks, fleas, lice and mites that attach or burrow into the skin and remain there for relatively long periods of time (e.g. weeks to months)

24
Q

Medically important ectoparasites

A
  • Mites(Scabies and trombiculid)
  • Ticks
  • Lice
  • Flies
25
Q

What does scabies cause?

A

§ Cause itchy rash that people may scratch off and this results in secondary infection

26
Q

What do you get trombiculid from?

A

§ Get it from walking around in the tropics in freshly grown grass

27
Q

Life cycle of parasite-Schistosomiasis

A

• Eggs of this parasite have been deposited in the water through human faeces so the water becomes contaminated
○ Eggs develop and infect the intermediate host – the snail
§ The snail becomes an amplifier
□ Asexual reproduction in snail releases thousands of developed eggs which infect humans when they walk in the contaminated water

28
Q

What can you measure morbidity to infection using?

A

• You can measure morbidity to infections using DALYs – Disease Adjusted Life Years

29
Q

What do opportunities for transmission depend on?

A
  1. Household sanitation
  2. Access to clean water
  3. Personal hygiene behaviours
30
Q

What are determinants of parasitic infections?

A
  1. Faeco-oral
  2. Food
  3. Complex life cycles
31
Q

What is protozoa(Chagas disease) transmitted by?

A

Transmitted by kissing bug

32
Q

How can you reduce the opportunity for transmission?

A

Simple measures such as improving construction of house, keeping animals away from house reducing opportunity for transmission

33
Q

What are the 3 phases of disease?

A
  1. Acute
  2. Chronic(Intermediate)
  3. Determinate chronic disease
34
Q

What can be detected in blood during acute phase of disease?

A

○ Trypanosomes can be detected in blood

35
Q

What percentage develop chronic chagas after acute disease?

A

○ 5-10% develop chronic Chagas immediately after acute disease

36
Q

What is determinate chronic disease characterised by?

A

○ Characterised by cardiac and intestinal disease

37
Q

What does acute chagas occur within?

A

• Occurs within 2-3 weeks

38
Q

What are generally mild symptoms of acute chagas?

A 
○ Local swelling (Romana)
○ Nodule or chagoma – rash on hand
○ Fever
○ Anorexia
○ Lymphadenopathy
39
Q

What are acute symptoms of acute chagas?

A

○ Hepatosplenomegaly

○ Acute myocarditis – rapid heart failure

40
Q

How do you develop chronic chagas(Cardiac)?

A

• Gradually develop chronic disease after 10-30 years

41
Q

What damage happens in chronic chagas(cardiac)?

A
  • Damage to conduction system of heart causing arrhythmias

* Damage to heart muscle causing cardiomyopathy

42
Q

What are most affected in chronic chagas(Digestive)?

A

• Oesophagus, rectum and sigmoid colon most affected

43
Q

What does chronic chagas interfere with?

A

• Interferes with peristalsis

§ Gut becomes unable to effectively move contents on so organs start to swell

44
Q

What is the presentation of chronic chagas(Megacolon)?

A

○ Constipation if it affects the large intestine

45
Q

What are complications involved with chronic chagas(megacolon)?

A 
○ Faecaloma
○ Obstruction
○ Sigmoid volvulus
○ Ulceration
○ Perforation
46
Q

What happens in the acute phase of chagas?

A

○ Tissue damage caused by inflammatory response to parasite in nests of amastigotes in cardiac, skeletal and smooth muscle
○ Parasite killing by antibodies, activated innate immune response and Th1 pro-inflammatory cytokines

47
Q

What happens in the intermediate phase of chagas?

A

○ Regulatory immune response characterised by IL-10 and IL-17
○ Balance between killing a parasite and protecting the host

48
Q

What happens in the chronic phase of chagas?

A

○ Chronic inflammatory response to persistent parasites in muscle and nerve cells
○ Autoimmune mechanisms
○ Damage to nerve and muscle cells resulting in loss of tolerisation so get response against host cells
○ May vary by parasite strain and tissue tropism
○ Predominance by Th1 cytokines and CD8+ T cells

Medical microbiology (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions