Amoebae Flashcards
What is a cyst?
Non-motile, environmentatlly resistant form serving often as the transmission state
What is a trophozoite?
This is the active, motile, growing stage
What are the amoebae we are concerned with?
Entamoeba histolytica
Entamoeba invadens
Acanthamoeba spp.
Naegleria fowleri
______ is associated with the disease amoebiasis and amoebic dysentery
Entamoeba histolytica
Intestinal amoebiasis is associated with what?
Variable secretory diarrhea, dysentery, and colitis
Extraintestinal amoebiasis is associated with what?
Liver abscesses (MAIN), peritonitis, and pleuropneumonia
Entamoeba histolytica has a _______ life cycle
Direct
How can an animal become infected with Entamoeba histolytica?
Ingestion of the cyst in food/water contaminated with feces
The mature cyst of Entamoeba histolytica contains how many nuclei?
4
What are 2 things about the adult Entamoeba histolytica
They inhabit the lower gut (LI, cecum, colon
The trophozoite reproduces asexually to form cysts
What is the infective form of Entamoeba histolytica? Is it zoonotic?
Cyst is the infective form
YES, thought to be, but only from humans to pets.
What are the classic lesions you’ll see in an Entamoeba histolytica infection?
Flask shaped ulcerations in the gut
How would you diagnose Antamoeba histolytica?
ID cysts in the feces
Fecal antigen test
Also realize that if the animal is positive, the humans associated with the animal are likely positive
Treatment for Entamoeba histolytica?
Metronidazole
________ causes a reptilian amoebiasis that is similar to Entamoeba histolytica
Entamoeba invadens
________ is often seen as a problem in captive snakes and turtles; especially in bearded dragons
Entamoeba invadens
How would you diagnosis Entamoeba invadens?
Same way you would Entamoeba histolytica. See trophozoites or cysts in feces.
How would you treat an animal infected with Entamoeba invadens?
Same as Entamoeba histolytica.
Metronidazole
_______ is a ubiquitous free-living organism that occurs in water, soil, and sewage
Acanthamoeba species
Acanthamoeba is an ________ parasite
accidental; it enters via respiratory tract or break in the skin
What example did the Brewmaster give of humans becoming infected with Acanthomoebiasis?
Contact lens wearers; chronic conjunctivitis
What age of dog does Acanthamoebiasis usually infect?
Mainly in dogs less than a year old; affects the respiratory and nervous system
A dog comes in that is suffering from pneumonia and meningoencephalitis. What would be a possible differential?
Acanthomebiasis
How would you detect acanthomebiasis? How would you treat it?
Detect the trophooites and wrinkled double walled cysts in tissue or tracheal wash
No treatment known
______ is a freeliving parasite that affects mainly humans
Naegleria fowleri
What does Naegleria fowleri cause in humans? Can it affect animals?
It causes primary amoebic meningoencephalitis.
Yes it can, and it is almost always fatal
Where is Naegleria fowleri likely to be found?
Areas of thermally-enriched H2O
What is the transmission of Naegleria fowleri?
Trophozoites or cysts enter the nasal cavity.
What is the main concern with Naegleria fowleri?
Once they are in the nasal cavity, they migrate to the brain via the olfactory nerve
T/F Naegleria fowleri is usually asymptomatic
FALSE; this is rapidly fatal. Often diagnosed post-mortem
