AMOEBA
Trophozoite: feeds, multiplies, possess pseudopods (soft liquid stool)
Cyst: nonfeeding (formed stool)
Excystation: cyst to trophozoite
Encystation: trophozite to cyst
Intestinal Extraintestinal
E. histolytica E. gingivalis
E. hartmanii N. fowleri
E. coli Acanthamoeba
E. polecki
E. nana
I. butschlii
1.Entamoeba histolytica
Trophozoite
– progressive
– 1 nuclei
– Small and central karyosome
– Fine and even chromatin
– Fine granular cystoplasm (glass appearance)
– INGESTED RBC
Cyst
– spherical to round shape
– 1-4 nuclei
– Small and central karyosome
– Fine and even chromatin
– Fine granular cytoplasm
– Chromatoid bars, diffuse glycogen mass
● wet preparation
● Special medium: TYI-S-33 in culture
● Excystation occurs in small intestine
● Single cyst = 8 motile trophozoite
● Replicate by binary fission
● Encystation occurs in intestinal lumen
● Trophozoite if intestinal motility is rapid, Cyst if normal
● Colder climates
● Hand to mouth contaminatiok and food/water confam
● Also transferred thru unprotected sex
● Vectors: flies and cockroaches
● ONLY KNOWN PATHOGENIC INTESTINAL AMOEBA
● Range of symptoms 2 major factors: location and extent of tissue invasion
Asymptomatic Carrier - low virulence, immune system intact
Symptomatic Intestinal Amebiasis - suffer from amebic colitis. can transition to bloody and
mucoud amebic dysentery
Symptomatic Extraintestinal Amebiasis - resides in liver. forms and abscess. venereal and penile
amembiasis may also occur
Treatment
– Asymptomatic: paromomycin, diloxanide, metronidazole (PDM)
– Symptomatic: paromomycin, diloxanide, iodoquinol (PDI)
– Extraintestinal: metronidazole or tinidazole (MT)
Prevention
– Infective cyst is resistant to chlorine
– Boil the uncontaminated water
Notes
– PCR differs E. histolytca to non patho amoeba
2.Entamoeba hartmanni
Major difference compared to histolytica (bigger) is the size
Trophozoite
– nonprogressive motility
– 1 nuclei
– Small and central karyosome
– Fine and even chromatin
– Fine granular cytoplasm
– INGESTED BACTERIA
Cyst
– spherical
– 1-4 nuclei
– Small and central karyosome
– Fine and even chromatin
– Fine granular cytoplasm
– Chrimatoid bars, diffuse glycogen mass
● uses ocular micrometer to identify
● Ingestion of infected cyst in contaminated food and water
● Asymptomatic usually and nonpathogenic
● Good sanitation and personal hygiene
● "SMALL RACE"
3.Entamoeba coli
Trophozoite
– nonprogressive, BLUNT motility
– 1 nuclei
– Large, irregular, eccentric karyosome
– Uneven chromatin
– Coarse and granulated cytoplasm
– Vacuoles contain bacteria
Cyst
– round and spherical
– 1-8 nuclei
– Large, irregular, eccentric karyosome
– Uneven chromatin
– Coarse and granulated cytoplasm
– Diffuse glycogen mass, thin chrimatoid bars with pointed to splintered ends
● ingestion of infected cyst thru contaminated food and drink
● asymptomatic and nonpathogenic
4.Entamoeba polecki
Trophozoite
– normal stools: sluggish, nonprogressive
– diarrheal stools: progressive, unidirectional
– 1 nuclei
– Small and central karyosome
– Fine and even chromatin
– Granular and vacuolated cytoplasm
– INGESTED BACTERIA
Cyst
– spherical or oval
– 1 nuclei
– Small and central karyosome
– Fine and even chromatin
– Granular cytoplasm
– Chromatoid bars, angular/pointed ends,
● nonglycogen
● Parasite of pigs and monkeys
● Human to human or pig to human
● Specimen: stool
Treatment
– metronidazole effective alone but can combine with diloxanide
5.Endolimax nana
BLOT LIKE
Trophozoite
– sluggish, nonprogressive, blunt
– 1 nuclei
– Large irregular blotlike karyosome
– No chromatin
– Granulat and vacuolated cytoplasm
– BACTERIA INCLUSION
Cyst
– spherical, ovoid, ellipsoid
– 1-4 nuclei
– Large blotlike central karyosome
– No chromatin
– Granular and vacuolated cytoplasm
– Nondescript small mass, diffuse glycogen mass
● WARM REGIONS
6.Iodamoeba butschlii
Trophozoite
– sluggish and progressive
– 1 nuclei
– Large central refractive achromatic granules karyosome
– No chromatin
– Coarse granular and vacuolated cytoplasm
– Bacteria, yeast cells and other debris
Cyst
– ovoid, ellipsoid, triangular and other shapes
– 1 nuclei
– Large central refractive achromatic granules karyosome
– No chromatin
– Coarse granular and vacuolated cytoplasm
– Well defined glycogen mass
● specimen: stool
● Iodine wet preparation (pick up by the glycogen mass)
● Glycogen unstained until trichrome staining
● Infective cyst ingested
● Hand to mouth transmission
● Nucleus DOES NOT undergo typical division
● Nucleus described as basket of flowers
● Some source of infection: contaminated hog feces
7.Entamoeba gingivalis
Trophozoite
– Active and varied motility
– 1 nuclei
– Centrally located karyosome
– Fine and even chromatin
– Fine granular cytoplasm
– Leukocyte, EC, bacteria
Cyst
– NO CYST
● specimen: MOUTH SCRAPINGS, vaginal and cervical, sputum
● ONLY amoeba with wbc
● Lives in the gum line of teeth
● Will not survive stomach juices
● Also found in intrauterine device. (IUD)
● Mouth to mouth contamination
● Pyorrhea alveolaris
● FIRST AMOEBA RECOVERED FROM HUMAN SPECIE
8.Naegleria fowleri
Has 3 morphologic forms
Ameboid Trophozoite
– Sluglike blunt pseudopods
– 1 nuclei
– Large centrally located karyosome
– No chromatin
– Granular and vacuolated cytoplasm
– ONLY EXIST IN HUMAN
Flagellate form
– pear shaped
– Jerky movements or spinning
– Large central karyosome
– No chromatin
– Granular and vacuolated cytoplasm
Cyst
– round and thick walls
● specimen: CSF (saline and iodine wet prep)
● TRAILING EFFECT on agar plate that was previously inoculated with gram negative bacili
● Acquired in swimming pool thats contaminated
● Warm bodies of water, summer
Clinical symptoms
> Primary Amebic Meningioencephalitis (PAM)
● Migrate to brain causing rapid tissue destruction
● death in 3-6 days
● Stiff neck and seizure
Treatment
– amphotericin b
– Ampho b with miconazole damage the cell wall
– Rifampicin inhibit RNA synthesis
● N. australiensis - mice, intranasal instillation
9.Acanthamoeba spp.
Trophozoite
– sluggish, SPINELIKE pseudopods
– 1 nuclei
– Large karyosome
– No chromatin
– Granular and vacuolated cytoplasm
Cyst
– roundish with RAGGED ENDS
– 1 nuclei
– Large and central karyosome
– No chromatin
– Disorganized, granular and vacuolated cytoplasm
– Double cell wall
● specimen: CSF, brain tissue, corneal scrapings (culture on non nutrient agar)
● Bacteria serves as a source of food for parasite
● Calcoflour white to stain acanthamoeba cyst
● Enters thru lower respiratory tract or ulcers then migrate via hematogenous spread thru
bloodstream
● Second route of infection is thru direct invasion of parasite in the eye (Acanthamoeba
keratitis)
● A. castellani - in CNS and eye
