Free Living Amoebas

What is the causative agent for Primary amoebic meningoencephalitis

Naegleria fowleri

What are the two causative agents for Granulomatous amoebic encephalitis?

Balamuthia mandrillaris and Acanthamoeba spp.

PAM is very _____ and _____, while GAE is _____ and more _____

fast; deadly; slower; chronic

What is the causative agent for keratitis?

Acanthamoeba spp.

What is the infectious stage for N. fowleri?

trophozoite

N. fowleri can transition between the _____ form, as well as a _____, and _____ form

cyst; trophozoite; flagellated

how is one infected with N. fowleri?

water up the nose

when N. fowleri trophozoites get up the nose, they travel to the _____ and cause _____

brain; PAM

What is the infectious stage for Acanthamboeba and B. mandrillaris?

trophozoites

how are humans infected with Acanthamoeba or B. mandrillaris?

respiratory tract or skin infection

Once humans are infected with Acanthamboema spp. or B. mandrillaris, they travel to the _____ and cause _____

brain; GAE

What type of water usually contains free-living ameba?

warm freshwater

N. fowleri cysts are common in _____ temperatures and _____ conditions

cooler; unfavorable

N. fowleri flagellates are most common in _____ concentrations and are _____ usually found in humans

low ion; NOT

N. fowleri trophozoites prefer _____ temperatues and can survive on _____ (ex. vivo) or _____ (in vivo)

warmer; bacteria; blood cells

What are the two forms of Amebic encephalitis?

Acute primary amebic meningoencephalitis (PAM) and Granulomatous amebic encephalitis (GAE)

What are the side effects associated with PAM?

severe headache/miningeal signs, fever, vomiting, neurological deficits

PAM can progress to _____ followed by _____ in about _____

coma; death; 10 days

PAM commonly occurs in _____ and _____ patients

children; young adults

PAM occurs in immuno-_____ individuals

COMPETENT!!!

All cases of PAM have a history of contact with contaminated _____

warm fresh water (Swimming/diving)

N. fowleri enter the brain via the _____ to cause PAM, and the disease is mostly _____

olfactory mucosa; fatal

PAM rates dramatically increase in the _____ months

summer

What is the causative agent for Granulomatous amebic encephalitis?

Acanthamoeba and Balamunthia spp.

What are the 3 main symptoms associated with GAE?

headaches; altered mental status, neurologic deficits

GAE symptoms progress over several _____ to death

WEEKS (slower moving than PAM)

GAE occurs primarily in immuno-_____ persons

SUPPRESSED

Acanthamoeba/Balamunthia spp. enter the brain by _____ spread from _____ or _____

hematogenous; respiratory tract; ulcerated skin

GAE can be _____, but is more commonly _____ to _____

fulminant; subacute; chronic

What condition is this?

GAE

What condition is this?

Skin infection of Acanthamoeba/Balamunthia spp. → can progress to GAE!!!

What condition is this? What parasite causes it?

Keratitis; Acanthamoeba spp.

Why is Naegleri fowleri so quickly to progress??

no cyst form in humans → Always on the go

about how big are N. fowleri trophozoites?

10-35um

What are the 3 main distinguishing features of N. fowleri?

granular vacuolated cytoplasm, single large nucleus, dense karyosome w/ NO peripheral chromatin

N. fowleri trophozoites are often associated with lots of _____

immune cells

How do you diagnose N. fowleri?

wet mount of CSF

N. fowleri is commonly diagnosed on _____

autopsy

How do you diagnose Acanthamoeba/Balamuthia?

microscopic exam of stained biopsies

what are the 3 most common biopsy locations for Acanthamoeba and Balamunthia infections?

brain, skin, cornea

Which organisms are there currently available molecular and IFA tests?

Acanthamoeba/Balamuthia

what type of molecular testing is done for Acanthamoeba/Balamuthia?

sequencing

What are the two most recognizable traits of Acanthamoeba spp. cysts?

staring, wrinkled outer wall and variable inner wall

how big are Acanthamoebe cysts?

10-25um

Acanthamoeba have no _____ trophozoite, unlike N. fowleri

flagellate

how big are Acanthamboeba spp. trophozoites?

15-45um

What is the defining feature of Acanamoeba trophozoites?

spine-like processes (acanthopodia)

What do B. mandrillaris cysts look like?

round, separate outer and inner wall

How big are B. mandrillaris cysts?

10-25um

how big are B. mandrillaris trophozoites?

15-60um

What is the defining feature of B. mandrillaris trophozoites?

long, seller pseudopodia

Which amoeba is this? What form?

Acanthamoeba spp. cyst

Which amoeba is this? What form?

B. mandrillaris trophozoite

Which amoeba is this? What form?

B. mandrillaris cyst

Which amoeba is this? What form?

N. fowleri, trophozoite

Which amoeba is this? What form?

Acanthamboeba spp. trophozoite

IFA assays are _____, but not _____

available; widely practiced

A _____ stain can be used to differentiate amoebas from macrophages

CD68 stain

Few patients typically survive _____ or _____ infections

N. fowleri; GAE

What is the typical treatment for N. fowleri?

LARGE doses of ampho B

Acanthamboeba and Balamuthia seem to be _____ to amphotericin B, but there are a few reported survivals with aggressive treatment using _____

resistant; pentamidine

Why are there not many treatment options for free living amoeba?

they are RARE → not a lot of opportunities to trial drugs

_____ and _____infections caused by Acanthamoeba infections are generally _____

eye; skin; treatable

What is used to treat Acanthamoeba spp. Keratinitis?

topic eyedrops or creams

Despite being incredibly dangerous, the risk of free living amoeba infection is _____

LOW

What is the causative agent for Keratitis?

Acanthamoeba spp.

Acanthamoeba causes painful _____ and _____ that follow corneal _____ or association with _____ use

keratitis; corneal ulcers; trauma; contact lens

True or False: Keratitis ONLY occurs in contact users, particular those with poor lens care practices

FALSE: non contact lens users and those with safe practices are STILL AT RISK

you have an increases risk of Acanthamoeba keratitis is you have _____ contact lens _____ and/or exposure to _____

poor; hygiene; contaminated water

There are some RARE cases of _____ of Acanthamoeba keratitis with _____ involvement, but it typically does NOT travel to the _____

dissemination; skin; brain