Non-pathogenic amoebae of man and reside in the large intestine of a human host
Entamoeba coli
(Entamoeba coli) The cysts are distinctive because they contain _______ nuclei and have _________ endosomes.
8 or more, eccentric
Despite its classification as a non-pathogen, Entamoeba coli can cause occasional diarrhea. True or False?
True
(Entamoeba coli) Motility
Sluggish, nondirectional, Granular pseudopodia
(Entamoeba coli) Karyosome
Eccentric
(Entamoeba coli) Peripheral Chromatin
Coarse and Clumped
(Entamoeba coli) Cytoplasmic Inclusions
Bacteria and other material but never RBCs
How are nuclei of Entamoeba coli different from Entamoeba histolytica?
E. histolytica has 4 nuclei in a mature cyst while E. coli has 8 nuclei in a mature cyst.
(Entamoeba coli) Chromatid Bodies
Filamentous, thread-like, pointed ends
(Entamoeba coli) Glycogen Mass
Large and visible in binucleate stage
(Entamoeba coli) Pathogenesis
E.coli is only a lumen parasite of the large intestine & is non-pathogenic.
(Entamoeba coli) Diagnosis
Definitive dx is the same as for E.histolytica, i.e. direct fecal smear for diarrheic stools containing the trophozoites.
(Entamoeba histolytica) Treatment
Is not necessary since it is non-pathogenic. This parasite is resistant to the usual anti-amoebic drugs.
How can Endolimax nana be differentiated from E. histolytica and E. coli?
Endolimax nana has much smaller size and appearance of the nucleus (a large endosome with little chromatin on the nuclear membrane).
Endolimax nana is the second most _______________ of humans.
endocommensal
(Endolimax nana) Habitat
Lives in the large intestine mainly near the cecum
(Endolimax nana) Outstanding feature
larger karyosome than those of the genus Entamoeba; absent peripheral chromatin
(Endolimax nana) Usually a commensal, seen in stool specimens from ______ patients, some literature suggesting it can cause intermittent or chronic diarrhea.
HIV/AIDS
(Endolimax nana) They feed exclusively on _________ and divide by __________.
bacteria, binary fission
(Endolimax nana) Karyosome
central or eccentric
(Endolimax nana) ________ nculei when cysts mature
4
(Endolimax nana) Motility
Sluggish
(Endolimax nana) Cytoplasmic inclusions
Bacteria, small vegetable cells and crystals
(Endolimax nana) Nucleus
Large irregular karyosome, arranged eccentrically with Achromatic strands
(Endolimax nana) _______ and __________ are absent
Chromidial bars, glycogen vacuole
(Endolimax nana) The cysts are excreted in feces and may survive for up to ________ when incubated at room temperature and for up to ____________ at lower temperatures; this, however, is under optimal conditions, and survival times are lower under natural settings such as in feces or water.
2 weeks, 2 months
(Endolimax nana) The main habitat is the large intestine, from the ______ to the ________.
cecum, rectum
(Endolimax nana) Trophozoites may survive in stool for up to _____ when feces is incubated at room temperature.
1 day
Non pathogenic intestinal amoeba; commonly found in the large intestines of people, pigs, and other mammals; an indicator of oral-fecal contamination and humans may experience diarrhea.
Iodamoeba bütschlii / Iodamoeba williamsi
(Iodamoeba bütschlii) May be _____ or ______ karyosome
central, somewhat eccentric
The cysts of I. bütschlii characteristically contain a large ____________ that makes it easy to distinguish from other species.
glycogen vacuole
(Iodamoeba bütschlii) Main habitat is the _________ and ___________ of the large intestine.
cecum, lumen
________________ comprise a large group of protozoa living in moist soil, decaying vegetation, and in all types of water especially water containing bacteria.
Free living amoeba
(Free living amoeba) 2 genera known to produce diseases in man
1. Naegleria fowleri (an amoeboflagellate)
2. Acanthamoeba castellani
Nagleria fowleri is also called _______________.
brain-eating amoeba
(Naegleria fowleri) Amoeba burrows into the ___________, multiplies, and migrates into the brain and surrounding structure.
nasal mucosa
Naegleria fowleri can cause _________________.
Primary amoebic meningoencephalitis (PAM)
(Naegleria fowleri) The microorganism is typically found in bodies of warm _________, such as ponds, lakes, rivers, and hot springs.
freshwater
(Naegleria fowleri) It can be seen in either an ______ or __________ stage.
amoeboid, temporary flagellate
3 forms of N. fowleri
-trophozoite or amoeboid form
-flagellate form
-cyst or resting form
(Naegleria fowleri) reproductive and infectious form
Trophozoite
(Naegleria fowleri) Reproduction
reproduce asexually (binary fission)
Naegleria fowleri does not form cysts in human tissue. True or False?
True
(Naegleria fowleri) Found in _______ and _______
CSF, tissue
(Naegleria fowleri) Form that is non-feeding and non dividing
Flagellate form
(Naegleria fowleri) Attaches to ____________ and heads to olfactory bulbs to feed on nerve tissue which results to _________ and __________.
-olfactory nerve
-necrosis, hemorrhaging
You can be infected with Naegleria fowleri by drinking contaminated water. True or False?
False
Infection by Naegleria fowleri is contagious. True or False?
False
(Naegleria fowleri) Acute fulminating infection generally occurs and the host usually dies within _________--.
1-2 weeks
(Naegleria fowleri) The death rate is over ____. Only ___ people have survived out of ____ known infected individuals in the United States from 1962 to 2021.
-97%
-4, 154
Naegleria fowleri grows best at higher temperatures up to _______.
115 degrees Fahrenheit (46 degrees C)
(Naegleria fowleri) ________ appears to make trophozoites nonviable instantaneously and cysts nonviable in <5 min.
Drying
Naegleria fowleri is a _______________ ameba able to grow and survive at higher temperatures, such as those found in hot springs and in the human body, even under fever temperatures.
heat-loving (thermophilic)
(Naegleria fowleri) Diagnostic Tools
Lumbar puncture (Analysis of CSF, indicated for by symptoms)
(Naegleria fowleri) Treatment
-"Heroic" dose of Amphotericin B (systematic antifungal)
-Miltefosine and Fluconazole (not FDA approved)
-Testing on Phenothiazine Antipsychotic Chlorpromazine
(Naegleria fowleri) PAM incubation period
1-14 days
(Naegleria fowleri) PAM has a rapid clinical course, death in ________ after onset of symptoms
4-5 days
(Naegleria fowleri) trophozoites can be detected in spinal fluid, but diagnosis is usually at _________
autopsy
(Naegleria fowleri) ___ known survivors treated with Amphotericin B
4
If Naegleria fowleri can cause PAM, Acanthamoeba spp can cause what?
granulomatous amebic encephalitis (GAE)
___________ is a genus of free-living amoebae that are present almost ubiquitously in the environment, they are commonly found in dust, soil and freshwater environments and they have also been isolated from swimming pools, cooling towers, air-conditioning systems and domestic tap water.
Acanthamoeba
(Acanthamoeba) Most species are free-living __________, but some are opportunists that can cause infections in humans and other animals.
(Acanthamoeba) Forms that can be source of infection
Trophozoite and Cyst
(Acanthamoeba) cysts 10-40 microns with __________ nucleus
centrally-placed
(Acanthamoeba) Round trophozoites are 12-45 microns; motile forms are 13-25 microns with slowly eruptive pseudopods (many of which appear as spine-like projections - _________)
acanthapodia
Acanthamoeba spp. are waterborne parasites very common in __________ aqueous environments.
unchlorinated
____________ serve as vectors for transmitting Acanthamoeba trophozoites.
Contact lenses
____________ is difficult to treat, and treatment is usually prolonged because of the ability of Acanthamoeba to form highly resistant cysts.
Acanthamoeba keratitis
(Acanthamoeba keratitis) When drug treatment is ineffective, a _______________ is required, and worse-case scenarios may result in _____________ of the eye.
corneal transplant, enucleation
(Acanthamoeba) incubation period
unknown but estimated at weeks to months
(Acanthamoeba) The route of infection is _________ or ____________ with hematogenous spread to the CNS.
aerosol, direct inoculation
(Acanthamoeba) Granulomatous Amebic Encephalitis or GAE is treated with ___________, usually in combination with other drugs.
pentamidine
(Acanthamoeba) Due to the rarity of this parasite and a lack of knowledge, there are currently no good diagnoses or treatments for Acanthamoeba infection. True or False?
True
Acanthamoeba has also been shown to support the intracellular replication and survival of human pathogenic bacteria such as Legionella pneumophila, Pseudomonas aeruginosa and Mycobacterium.
Additional info na murag need mahibal an
Acanthamoeba act as a reservoir for other microorganisms, protecting them from adverse conditions, therapeutic agents and disinfectants, while also enhancing their virulence in humans.
