E3- GI Protozoans Flashcards

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1
Q

How does Giardia lamblia present clinically?

A
  • Watery diarrhea (NO blood)

- Vitamin B12 deficiency

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2
Q

What type of pathogen is Giardia lamblia?

A

Zoonotic flagellate GI protozoan

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3
Q

What population does Giardia lamblia most commonly affect?

A

Children

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4
Q

What stage of Giardia lambli exists freely in the small intestine and feeds on mucosal secretions?

A

Trophozoite

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5
Q

What is the morphology of the trophozoite stage of Giardia lamblia?

A

Tear drop shaped with 2 nuclei

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6
Q

Does the trophozoite stage of Giardia lamblia invade or destroy RBCs?

A

No (no blood in diarrhea)

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7
Q

What is the infectious stage of Giardia lamblia?

A

Cysts

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8
Q

What form of Giardia lamblia is passed into the environment?

A

Cysts

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9
Q

What is the morphology of the cysts stage of Giardia lamblia?

A

4 nuclei (1 cysts produces 2 trophozoites)

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10
Q

How is Giardia lamblia acquired?

A

Ingestion of cysts (infectious stage) from contaminated food or water with feces

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11
Q

Once Giardia lamblia cysts have been ingested, what occurs next?

A
  • Ecystation and then the trophozoites move to into the small intestine to divide
  • Trophozoites encyst in neutral pH and bile salts
  • Cysts are passed into the environment (immediately infectious)
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12
Q

Why is Giardia lamblia highly contagious?

A

Cysts are immediately infectious
Infective dose = 10-25 cysts
>25 cysts = 100% infection rate

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13
Q

When are Giardia lamblia infections most prevalent?

A

June-october

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14
Q

Where geographically are Giardia lamblia infections most prevalent in the US?

A

Western states (Rocky mountains)

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15
Q

How is Giardia lamblia dx?

A
  • Stool sample

- ELISA to detect GSA-65

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16
Q

What type of pathogen is Entamoena histalytica?

A

Protozoan that can result in colitis and liver abcesses

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17
Q

What is the etiology of amoebiasis?

A

Entamoena histalytica

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18
Q

What stage of Entamoena histalytica (amoebiasis) is invasive and ingest RBCs?

A

Trophozoite (blood in stool)

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19
Q

What is the morphology of the trophozoite stage of Entamoena histalytica (amoebiasis)?

A
  • 1 nucleus
  • Non-flagellated
  • Pseudopod forming
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20
Q

What is the infectious stage of Entamoena histalytica (amoebiasis)?

A

Cysts

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21
Q

What is the morphology of the cysts stage of Entamoena histalytica (amoebiasis)?

A

4 nuceli (1 cyst produces 4 trophozoites)

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22
Q

How is Entamoena histalytica (amoebiasis) transmitted?

A

Ingestion of cysts (infectious stage) from contaminated water or food with feces

23
Q

Once Entamoena histalytica cysts have been ingested, what occurs next?

A
  • Excystation, which forms highly motile trophozoites that colonize the mucosa
  • The trophozoites may encysts and be passed in feces OR
  • The trophozoites may invade the intentional mucosa/bloodstream
24
Q

Which GI protozoan infection is a reportable disease?

A

Entamoena histalytica (amoebiasis)

25
Q

Which GI protozoan infection can cause disseminated disease?

A

Entamoena histalytica (amoebiasis)

26
Q

What is the clinical presentation of Entamoena histalytica (amoebiasis)?

A
  • Bloody stools
  • Intestinal ulcers
  • Fever
  • R. upper quadrant pain
27
Q

What are the virulence factors of Entamoena histalytica (amoebiasis)? (4)

A
  • Lectin
  • Phospholipases
  • Ameobapore
  • Cystein proteases
28
Q

How is Entamoena histalytica (amoebiasis) dx?

A
  • Stool sample

- ELISA (can differentiate from other Entamoena spp)

29
Q

Are Entamoena histalytica (amoebiasis) cysts resistant to chlorine?

A

Yes

30
Q

What population does Cryptospordiosis hominis most commonly affect?

A

Children

31
Q

What is the presentation of Cryptospordiosis hominis in healthy individuals?

A

Self-limiting watery diarrheal illness that lasts ~2 weeks (NO blood)

32
Q

What population can Cryptospordiosis hominis cause severe illness in?

A

Immunocompromised

33
Q

What is the infectious stage of Cryptospordiosis hominis?

A

Oocysts

34
Q

What is the morphology of Cryptospordiosis hominis’s oocysts?

A

Contain 4 sporozoites

35
Q

Can Cryptospordiosis hominis multiply outside of the hosts?

A

No

36
Q

How is Cryptospordiosis hominis transmitted?

A

Ingestion of oocyst (infectious stage)

37
Q

Once Cryptospordiosis hominis oocysts have been ingestion, what occurs next?

A
  • The oocysts is activated to release its 4 sporozoites
  • Sporozoites bind to receptors on intestinal epithelial cells and are ingested into parasitophorous vacules
  • Parasite undergoes sexual and asexual reproduction
38
Q

What protozoan is ingested into parasitophorous vacules?

A

Cryptospordiosis hominis

39
Q

What type of replication does Cryptospordiosis hominis undergo?

A

Sexual and asexual

40
Q

Through what type of reproduction are thin walled oocyst produced in C. hominis? What this their purpose?

A
  • Asexual

- Reinfect the host

41
Q

Through what type of reproduction are thick walled oocyst produced in C. hominis? What is their purpose?

A
  • Sexual

- Shed into the environment (immediately infectious)

42
Q

How are endemic cases of Cryptospordiosis hominis usually transmitted?

A

Person-to-person

43
Q

How are sporadic cases of Cryptospordiosis hominis usually transmitted?

A

Contaminated water or food

44
Q

Is Cryptospordiosis hominis resistant to chlorine?

A

Yes

45
Q

How is Cryptospordiosis hominis dx?

A
  • ID of round acid fast oocyst in stool sample

- ELISA

46
Q

What type of pathogen is Cyclosporiasis cayetanesis?

A

Diarrheagenic Protozoan

47
Q

What geographic location is Cyclosporiasis cayetanesis linked to?

A

Latin America

48
Q

How can you differentiate the oocyst from Cryptospordiosis hominis from the oocyst from Cyclosporiasis cayetanesis?

A

The oocyst from Cyclosporiasis cayetanesis is much larger and is autofluorescent

49
Q

How is Cyclosporiasis cayetanesis transmitted?

A

Ingestion of oocysts from contaminated water or imported foods (fruits and vegetables)

50
Q

What is different about the oocysts infectability in Cyclosporiasis cayetanesis?

A
  • Oocyst shed in feces must sporulate in the environment

- NOT immediately infectious

51
Q

What is the clinical presentation of Cyclosporiasis cayetanesis?

A

Explosive watery diarrhea (NO blood)

52
Q

How is Cyclosporiasis cayetanesis dx?

A
  • ID large oocysts in stool samples

- ID acid fast autofluorescent oocyst

53
Q

What GI protozoan has a large central vacuole and multiple nuclei distributed around the rim of the cytoplasm?

A

Blastocytis hominis

54
Q

What GI protozoan is zoonotic (pigs), contains a macronucleus, has cilia on the trophozoite stage, and can cause gut perforation?

A

Balantidium coli