Lec45 Enteric Protozoa Flashcards
(65 cards)
1
Q
What is entamoeba histolytica [amebiasis] transmission?
A
- fecal oral
- food/water contaminated with infective cysts
- oral-anal sexual contact
2
Q
Where are majority of entamoeba infetions? who is at risk?
A
in developing countries
at risk: recent immigrants, MSM
3
Q
What does trichomonas vaginalis cause?
A
parasite UTI
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
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
6
Q
What is treatment of choice for entamoeba histolytica?
A
- metronidazole [or tinidazole because fewer side effects]
= + iodoquinol to kill cysts
7
Q
What is mech of action metronidazole?
A
upsets electron balance within paraste
8
Q
What do you use to kill entamoeba cysts?
A
iodoquinol
9
Q
how do you diagnose entamoeba?
A
- serology
- parasite cyst in stool
10
Q
What is balamuthia? route of infection?
A
- free living amoeba
- transmit = direct innoculation into nares
11
Q
What are clinical brain complications of balmuthia?
A
- progressive meningoencephalitis that does not usually respond to therapy
12
Q
What are the 3 types of free living amoeba?
A
- acanthamoeba species
- balamuthia mandrillaris
- naegleria fowleri
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
14
Q
How are free living amoeba present in environment?
A
- as trophozoites or cysts
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
16
Q
What does naegleria encephalitis cause? spread?
A
- primary amoebic encephalitits
- direct innoculation in fresh water
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
18
Q
What is source of giardia lamblia?
A
- ingest cysts in contaminated water/food/fecal-oral contact
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!!
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
21
Q
Is giardia invasive?
A
No!
22
Q
How do you diagnose giardia?
A
- direct florescent antibody to giardia antigen
- cysts in stool
23
Q
What is incubation period of giardia?
A
5-20 days
24
Q
Where is geo of giardia?
A
world wide, north america
25
What is treatment for giardia?
- tinidazole or metronidazole [Flagyl]
26
What does trichomonas vaginalis commonly cause?
- vaginitis, cervicitis, vaginal discharge, pruritis/irrritation
- usually asymptomatic in males or may have urethritis
27
Does trichomonas vaginalis have cyst form?
nope
28
how is trichomonas vaginalis transmitted?
- sexually transmitted, women more symptomatic
29
what should you avoid on tinidazole?
avoid alcohol completely --> can feel flushed/fever/ab pain/life threatening
30
What other diseases co-occur with trichomonas vaginalis?
- associated with other STDs [especially gonorrhoea]
| - bacterial vaginosis
31
How do you diagnose trichomonas?
- wet prep exam --> detect very motile organisms
32
What are complications of trichomonas in pregnant woman?
- low birth weight, pre term delivery, premature rupture of membranes
33
What is relation trichomonas and HIV?
- if you have trichomonas, you are at higher risk for contracting HIV / have higher viral load
34
Where do you see trichomonas?
- worldwide --> higher in people with multiple sex partners or other venereal disease
35
How do you treat trichomonas?
- systemic or intravaginal sopositories of metronidazole or tinidazole
- partner treatment
36
Why is tinidazole sometimes better than metronidazole?
it has fewer side effects
37
What are associations to differentiate trichomonas vaginalis, trichuris trichiura, trichinella spiralis?
trichomonas vaginalis: vaginitis
trichuris trichiura: whipworm, rectal prolaspe
trichinella spiralis: consumption of wild boar
38
How do you get trichinella spiralis?
- ingest larvae encysted in undercooked meat [pork]
39
What is pathogenesis of trichinella infection?
- larvae ingested
- larvae mature in intestine, females deposit new larvae
- larvae penetrate bowel and enter circulation
- larvae penetrate skeletal muscle, cause inflammatory response
40
What are clinical features of trichinosis spiralis?
- fever, myalgias, orbital edema, elevated CPK, eosinophilia
41
How do you confirm trichinosis spiralis diagnosis?
- by muscle biopsy = spiral shaped appearance or serology
42
What is treatment for trichinosis spiralis?
- mebendazole and steroids
43
Where do you see t spiralis infection?
temperate climates, northa america, europe, south america, asia
44
What animals get infected with T spiralis?
- polar bears, walruses, wild bears, boars
45
What is distribution of intestinal spore-forming protozoa?
- worldwide
46
How do you diagnose intestinal spore forming protozoa?
- visualize parasite with acid fast of stool
| - immunostatin [DFA to cryptosporidium]
47
What are the four intestinal spore-forming protozoa?
- cryptosporidium, isospora, cyclospora, microsporidium
48
How do you treat the 4 intestinal spore forming protozoa?
- immune reconstitituion [for microsporidia. cryptosporidia]
- nitazoxanide
- trimethoprim/sulfa [isospora, cyclospora]
49
What are clinical signs of intestinal spore forming protozoa?
- severe watery diarrhea usually in immunocompromised
50
What is mech of transmission intestinal spore forming protozoa?
ingestion of cyst form
51
What is life cycle of cryptosporidium parvum?
- entire cycle wthin enterocytes
- ingestion of oocyte spores begins life
- has asexual and sexual cycles
- leads to autoinfection cycle
52
How is cryptosporidium parvum transmitted?
- ingestion of oocytes from contaminated food/water/recreational water [water park, rafting]
- can get it from feces of animal reservoirs [cattle/sheep]
53
What are clinical signs of cryptosporidium parvum
- voluminous diarrhea, bloating, malabsorption
54
What does cryptosporidium cause in HIV? in immunocompetent?
HIV: wasting syndrome
competent: diarrhea/bloating
55
Cryptococcus vs cryptosporidium?
Cryptococcus: opportunistic pneumonia/meningitis
cryptosporidium: opportunistic GI
56
What is life cycle of isospora? appearance?
sexual and asexual stages
| eye appearance on biopsy
57
Where is isospora belli endemic?
Africa, asia, south america
58
how do you detect isosospora?
acid fast stain
59
What is cyclospora associated with?
- multistate food outbreaks: lettuce, rasberrries
60
Where is cyclospora cayetanensis found?
- worldwide distribution
61
What clinical findings of cyclospora cayetanensis?
- protracted relaspsing gastroenteritis
| - in immunocompromised: profound watery diarrhea --> death
62
What is pathogenesis of cyclospora cayetanensis?
- oocysts secreted unsporulated
- after days - wks outside host, sporulate and become infectious
- mature oocyte ingested
63
What are features of microsporidium cell?
- nucleated
- single celled obligate intracellular protozan parasite
- lacks mitochondria
- has polar tube
64
Who does microsporidium infect? geo distribution?
- broad range vertebrates, invertebrates
- very rarely see in immmunocompetent
- get it from water, animals, food producing farm animals
65
What are clinical signs of micropsoridium?
- 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
