Amebae & Balantidium (Lecture 6)

what are the two main categories of diarrhea?

acute and chronic

wat are some things to consider when someone has diarrhea? (5)

blood, weight loss, immune status, fatty stools, onset relative to exposure

what are the two main approaches to diarrhea?

presumptive diagnosis and treatment or laboratory-based diagnosis

Presume diagnosing and treatment is often made for _____, _____, and _____

returning travelers; known outbreaks; acute food poisoning

what are the 4 main things that are used for laboratory based diagnosis of diarrhea?

stool culture, O&P, PCR, Fecal fat analysis

what does O&P stand for?

ovum and parasite

PCR panels are not ideal because they are very _____

expensive

what are the 5 main tests used for a Stool O&P?

wet mount, concentration smear, permanent stain, antigen testing, PCR panel

a stool wet mount is _____ but not the most _____

fast; specific

what is the “gold standard” of permanent Stool O&P stains?

trichrome

PCR is typically reserved for _____ patients

advanced

Ova, aka _____, are she by _____ in the GI tract or elsewhere

egs; adult worms

what are the two main life stages in the typical fecal-oral life cycle?

cyst and trophozoite

the trophozoite stage is the _____ form

active

the cyst stage is the _____ form

dormant

which stage of the fecal oral life cycle is feeding, motile, and doing replication?

trophozoite

what stage of the fecal-oral life cycle is passed in the feces?

cyst

what stage of the fecal oral life cycle is resistant and infectious?

cyst

what is the process of turning from a cyst to a trophozoite?

excystation

what is the process of turning from a trophozoite to a cyst?

encystation

Amebiasis is in the USA is often associated with _____ infection, and a majority of the fatal cases occurred in _____ and _____

HIV; CA; TX

amebiasis in the UDA is mostly in US-born persons, but all fatalities are in the _____ and _____ populations (of which 60% were _____-born)

asian/Pacific Islander; hispanic; foreign

what does histolytic mean?

dissolves tissue

what is the geographic distribution of E. histolytica?

worldwide

E. histolytica is a major cause of death in _____ worldwide

children

true or false: all species of entamoeba are pathogenic

FALSE: some colonize humans with no disease (ex. E. dispar)

E. histolytic is _____ and is associated with both _____ and _____ infections

pathogenic; intestinal; extraintestinal

E. dispar is morphologically _____ from E. histolytica and is generally _____ considered pathogenic

indistinguishable; not

what is the primary feature that is used to differentiate E. histolytica from E. dispar?

erythrophagocytosis

_____ are the primary reservoir for E. histolytica?

humans

how does the infection of E. histolytica occur?

mature cysts ingested

trophozoites are _____ while cysts are _____

labile; hardy

excystation of the E. histolytica occurs in the _____ which leads to the _____ form

small intestine; trophozoites

E. histolytica trophozoites colonize the _____ where they undergo _____ to form more _____ or _____

large intestine; multiplication; trophozoites; cysts

how are E. histolytica cysts released into the environment?

shed in stool

_____% of E. histolytica cases will get infection of the liver, lung, or brain

10

asymptomatic infection of amebiasis is also known as _____, and is caused by commensals like _____

luminal amebiasis; E. dispar

invasive intestinal amebiasis is when the parasite invades the _____ but is still localized to the _____

intestinal epithelial cells; intestine

what are the 4 main symptoms of invasive intestinal amebiasis?

dysentery/UC, appendicitis, toxic mega colon, amebomas

what are the 4 main symptoms of invasive extra intestinal amebiasis?

liver abscess, cutaneous/genital amebic lesions, brain hemorrhage; pleuropulmonary abscess

when looking at intestinal histology of E. histolytica, it is common to see _____ and _____ where the parasite has invaded the _____

flask-shaped ulcers; granulomas; epithelial cells

what is this called?

invasive extra intestinal amebiasis (w/ advanced cutaneous disease)

E. histolytica amebic brain abscess show _____ of the brain tissue

deterioration

the first step of diagnosing amebiasis is _____

trying to see the parasite

how is amebiasis ruled out?

3x stool exam

why do 3 stool exams when ruling out amebiasis?

increases sensitivity

stool exam can be done with either a _____ or a _____

wet mount; permanent stain

_____ techniques are used when diagnosing amebiasis, especially for visualizing cysts

concentration

concentration techniques CANNOT be used for _____ tests due to _____

EIA/antigen-based; antigen loss (false NEGATIVES!)

biopsies primarily show the _____ stage

trophozoite

aside from laboratory diagnosis, _____, _____ and _____, are done when diagnosing Amebiasis

liver scan, CT, ultrasound

trophozoites are usually found in _____ stool, while cysts are in _____ stool

diarrheal; formed

how big are E. histo/dispar trophozoites?

15-20um

what is erythrophagocytosis? What amebae is this a clue for?

ingestion of RBCs; E. histo

what are 3 main main features of E. histo/dispar trophozoites?

central karyosome, peripheral chromatin, ground class cytoplasm

what is this an example of?

erythrophagocytosis

if you do NOT see erythrophagocytosis, can you rule out E. histo?

NO!

what is this called?

chromatid body

E. histo has a chromatid body with _____, _____ ends

blunt; rounded

what type of stain is ideal for showing the chromatid body?

trichrome stain

If you CANT see the parasite, use _____ or _____ assays

immuno; molecular

fecal _____ can serve as an additive to microscopy

antigen EIA

what are the 3 main immune or molecular assays used to diagnose amebiasis If you cannot visualize the parasite?

fecal antigen EIA, multiplex PCR, serology

serology is primarily useful in _____ disease

extraintestinal

why isn’t serology useful for intestinal disease?

not as sensitive (intestines gen. have a low antibody response)

serology for extra intestinal disease is highly _____ but it cannot differentiate _____

specific; new vs. past infection

E. dispar is _____ more frequent than E. histo; and they can be distinguished by _____ or _____ assays

10x; immunologic; molecular

E. histo must be differentiated from other _____, which are for the most part _____

intestinal protozoa; asymptomatic

what are the 5 other intestinal amebae that H. histo must be differentiated from?

E. hartmanni, E. coli, E. polecki, E. nana, I. beutschlii

E. coli cysts have _____ nuclei, an _____ karyosome, and is typically between _____um

8+; eccentric; 10-35

E. coli trophozoite has _____ nucleus/ei with a _____ cytoplasm and is typically between _____ um

ONE; dirty/vacuolated; 10-50

E. hartmanni is very similar to _____ but _____

E. histo; smaller

E hartmanni cysts are typically _____ um and have a _____, similar to E. histo, but _____

5-10; chromatid body, smaller

E. hartmanni trophozoites has a _____/_____ karyosome and is typically _____ um

small; compact; 5-15

what is the primary distinguishing feature of Endolimax nana cysts?

lack peripheral chromatin (only see karyosome)

how big are Endolimax nana cysts?

5-10um

what is the primary distinguishing feature of Endolimax nana trophozoites?

irregular blot-like karyosome

how big are E. nana trophozoites?

6-12 um

what is the primary distinguishing feature of I. beutschlii cysts?

one LARGE glycogen vacuole

what is the primary distinguishing feature of I. beutschlii trophozoites?

large central karyosome

how big are I. buetschlii cysts?

5-20um

how big are I. beutschlii trophozoites?

8-20um

what is the primary distinguishing feature if E. polecki?

many small chromatid bodies (w/ pointed ends)

E. polecki rarely causes _____ symptoms in humans

mild

Dientamoeba fragilis is a _____ NOT an _____

flagellate; ameba

how does D. fragilis differ from the rest of the amebas (other than it being a flagellate)?

only has trophozoite stage, no cysts

D. fragilis causes both _____ and _____ infections

symptomatic; asymptomatic

what is the primary distinguishing features of D. fragilis trophozoites?

2 nuclei (inclusion possible)

What Amebae is this? Is this the trophozoite or cyst form?

E. histo/dispar; trophozoite

What Amebae is this? Is this the trophozoite or cyst form?

E. coli; trophozoite

What Amebae is this? Is this the trophozoite or cyst form?

E. hartmanni; cyst

What Amebae is this? Is this the trophozoite or cyst form?

E. histo/dispar; cyst

What Amebae is this? Is this the trophozoite or cyst form?

E. polecki; cyst

What Amebae is this? Is this the trophozoite or cyst form?

E. hartmanni; trophozoite

What Amebae is this? Is this the trophozoite or cyst form?

E. nana; trophozoite

What Amebae is this? Is this the trophozoite or cyst form?

E. coli; cyst

What Amebae is this? Is this the trophozoite or cyst form?

E. nana; cyst

What Amebae is this? Is this the trophozoite or cyst form?

E. polecki; trophozoite

What Amebae is this? Is this the trophozoite or cyst form?

I. beutschlii; trophozoite

What Amebae is this? Is this the trophozoite or cyst form?

I. beutschlii, cyst