Lec45 Enteric Protozoa Flashcards

1
Q

What is entamoeba histolytica [amebiasis] transmission?

A
  • fecal oral
  • food/water contaminated with infective cysts
  • oral-anal sexual contact
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2
Q

Where are majority of entamoeba infetions? who is at risk?

A

in developing countries

at risk: recent immigrants, MSM

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3
Q

What does trichomonas vaginalis cause?

A

parasite UTI

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4
Q

What is life cycle of entamoeba?

A
  • two stage life cycle
  • –> infective cyst
  • –> multiplying trophozoite
  • ingest cyst form
  • see trophozoite form in biopsies, both passed in feces
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5
Q

What are clinical signs of entamoeba?

A
  • may have just normal diarrhea, little symptoms
  • amebic dysentery = stool with blood, mucous, pus
  • amebic colitis = flask shaped ulcer

travels systemically in <1%:

  • amebic liver abscess= anchovy paste aspirate, often do not show trophozoites in aspirate, use serology
  • pulmonary abscess/pleural effusion
  • brain abscess
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6
Q

What is treatment of choice for entamoeba histolytica?

A
  • metronidazole [or tinidazole because fewer side effects]

= + iodoquinol to kill cysts

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7
Q

What is mech of action metronidazole?

A

upsets electron balance within paraste

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8
Q

What do you use to kill entamoeba cysts?

A

iodoquinol

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9
Q

how do you diagnose entamoeba?

A
  • serology

- parasite cyst in stool

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10
Q

What is balamuthia? route of infection?

A
  • free living amoeba

- transmit = direct innoculation into nares

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11
Q

What are clinical brain complications of balmuthia?

A
  • progressive meningoencephalitis that does not usually respond to therapy
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12
Q

What are the 3 types of free living amoeba?

A
  • acanthamoeba species
  • balamuthia mandrillaris
  • naegleria fowleri
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13
Q

How do you distinguish between parasitic amoeba and free living amoeba?

A
  • free living almost invariably kill hosts
  • not dependent on host for transmission
  • no host to host trans
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14
Q

How are free living amoeba present in environment?

A
  • as trophozoites or cysts
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15
Q

How is free living amoeba transmitted?

A
  • no person to person transmission
  • acquired by direct inoculation or inhalation of cysts
  • via nares or skin
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16
Q

What does naegleria encephalitis cause? spread?

A
  • primary amoebic encephalitits

- direct innoculation in fresh water

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17
Q

What does acanthamoeba cause? spread?

A
  • acanthamoeba meningoencephalititis
  • infection associated with contact lens = severe keratitis
  • direct innoculation in fresh water through nasal passage or broken skin

only need to ingest < 10 cysts

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18
Q

What is source of giardia lamblia?

A
  • ingest cysts in contaminated water/food/fecal-oral contact
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19
Q

What are signs of giardia lamblia?

A
  • 25% asymptomatic
  • diarrhea, cramps, bloating, nausea
  • may be constant or intermittent, last wks
  • chronic diarrhea and malabsorption/weight loss may follow acute infection even with treatment
  • fever / GI bleeds unusual = noninvasive

sulfur burps!!

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20
Q

What is mech of giardia lamblia infection/life?

A
  • ingest cyst
  • gastric acid –> excystment of cyst into trophocoites in proximal small intestine
  • absorbs nutrients from host, inhibiis host digestive enzymes
  • possible diffuse loss of brush border
  • zoonotic reservoirs
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21
Q

Is giardia invasive?

A

No!

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22
Q

How do you diagnose giardia?

A
  • direct florescent antibody to giardia antigen

- cysts in stool

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23
Q

What is incubation period of giardia?

A

5-20 days

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24
Q

Where is geo of giardia?

A

world wide, north america

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25
Q

What is treatment for giardia?

A
  • tinidazole or metronidazole [Flagyl]
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26
Q

What does trichomonas vaginalis commonly cause?

A
  • vaginitis, cervicitis, vaginal discharge, pruritis/irrritation
  • usually asymptomatic in males or may have urethritis
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27
Q

Does trichomonas vaginalis have cyst form?

A

nope

28
Q

how is trichomonas vaginalis transmitted?

A
  • sexually transmitted, women more symptomatic
29
Q

what should you avoid on tinidazole?

A

avoid alcohol completely –> can feel flushed/fever/ab pain/life threatening

30
Q

What other diseases co-occur with trichomonas vaginalis?

A
  • associated with other STDs [especially gonorrhoea]

- bacterial vaginosis

31
Q

How do you diagnose trichomonas?

A
  • wet prep exam –> detect very motile organisms
32
Q

What are complications of trichomonas in pregnant woman?

A
  • low birth weight, pre term delivery, premature rupture of membranes
33
Q

What is relation trichomonas and HIV?

A
  • if you have trichomonas, you are at higher risk for contracting HIV / have higher viral load
34
Q

Where do you see trichomonas?

A
  • worldwide –> higher in people with multiple sex partners or other venereal disease
35
Q

How do you treat trichomonas?

A
  • systemic or intravaginal sopositories of metronidazole or tinidazole
  • partner treatment
36
Q

Why is tinidazole sometimes better than metronidazole?

A

it has fewer side effects

37
Q

What are associations to differentiate trichomonas vaginalis, trichuris trichiura, trichinella spiralis?

A

trichomonas vaginalis: vaginitis

trichuris trichiura: whipworm, rectal prolaspe

trichinella spiralis: consumption of wild boar

38
Q

How do you get trichinella spiralis?

A
  • ingest larvae encysted in undercooked meat [pork]
39
Q

What is pathogenesis of trichinella infection?

A
  • larvae ingested
  • larvae mature in intestine, females deposit new larvae
  • larvae penetrate bowel and enter circulation
  • larvae penetrate skeletal muscle, cause inflammatory response
40
Q

What are clinical features of trichinosis spiralis?

A
  • fever, myalgias, orbital edema, elevated CPK, eosinophilia
41
Q

How do you confirm trichinosis spiralis diagnosis?

A
  • by muscle biopsy = spiral shaped appearance or serology
42
Q

What is treatment for trichinosis spiralis?

A
  • mebendazole and steroids
43
Q

Where do you see t spiralis infection?

A

temperate climates, northa america, europe, south america, asia

44
Q

What animals get infected with T spiralis?

A
  • polar bears, walruses, wild bears, boars
45
Q

What is distribution of intestinal spore-forming protozoa?

A
  • worldwide
46
Q

How do you diagnose intestinal spore forming protozoa?

A
  • visualize parasite with acid fast of stool

- immunostatin [DFA to cryptosporidium]

47
Q

What are the four intestinal spore-forming protozoa?

A
  • cryptosporidium, isospora, cyclospora, microsporidium
48
Q

How do you treat the 4 intestinal spore forming protozoa?

A
  • immune reconstitituion [for microsporidia. cryptosporidia]
  • nitazoxanide
  • trimethoprim/sulfa [isospora, cyclospora]
49
Q

What are clinical signs of intestinal spore forming protozoa?

A
  • severe watery diarrhea usually in immunocompromised
50
Q

What is mech of transmission intestinal spore forming protozoa?

A

ingestion of cyst form

51
Q

What is life cycle of cryptosporidium parvum?

A
  • entire cycle wthin enterocytes
  • ingestion of oocyte spores begins life
  • has asexual and sexual cycles
  • leads to autoinfection cycle
52
Q

How is cryptosporidium parvum transmitted?

A
  • ingestion of oocytes from contaminated food/water/recreational water [water park, rafting]
  • can get it from feces of animal reservoirs [cattle/sheep]
53
Q

What are clinical signs of cryptosporidium parvum

A
  • voluminous diarrhea, bloating, malabsorption
54
Q

What does cryptosporidium cause in HIV? in immunocompetent?

A

HIV: wasting syndrome
competent: diarrhea/bloating

55
Q

Cryptococcus vs cryptosporidium?

A

Cryptococcus: opportunistic pneumonia/meningitis
cryptosporidium: opportunistic GI

56
Q

What is life cycle of isospora? appearance?

A

sexual and asexual stages

eye appearance on biopsy

57
Q

Where is isospora belli endemic?

A

Africa, asia, south america

58
Q

how do you detect isosospora?

A

acid fast stain

59
Q

What is cyclospora associated with?

A
  • multistate food outbreaks: lettuce, rasberrries
60
Q

Where is cyclospora cayetanensis found?

A
  • worldwide distribution
61
Q

What clinical findings of cyclospora cayetanensis?

A
  • protracted relaspsing gastroenteritis

- in immunocompromised: profound watery diarrhea –> death

62
Q

What is pathogenesis of cyclospora cayetanensis?

A
  • oocysts secreted unsporulated
  • after days - wks outside host, sporulate and become infectious
  • mature oocyte ingested
63
Q

What are features of microsporidium cell?

A
  • nucleated
  • single celled obligate intracellular protozan parasite
  • lacks mitochondria
  • has polar tube
64
Q

Who does microsporidium infect? geo distribution?

A
  • broad range vertebrates, invertebrates
  • very rarely see in immmunocompetent
  • get it from water, animals, food producing farm animals
65
Q

What are clinical signs of micropsoridium?

A
  • in immunocompetent travelers: self limiting or chronic diarrhea [very rare]
  • in compromised: chronic diarrhea [more intense], can disseminate –> encephalitis, sinuses, nephritis, hepatitis
  • AIDS related eye infections