Intestinal Protozoa Flashcards
Entamoeba histolytica trophozoite
10-60 um
Finely granular cytoplasm with ingested RBCs
Nucleus has central karyosome
Pseudopods are rapid and unidirectional motility (progressive)
Fragile
Entamoeba histolytica trophozoite
Entamoeba histolytica cyst
10-20 um
Infective form
Finely granular, slightly vacuolated cytoplasm
Cysts can have up to four nuclei
Nucleus has central karyosome
Chromatoidal bars (if present) have rounded ends
Resistant to environmental conditions and remain viable for 8 days
Entamoeba histolytica cyst
Entamoeba histolytica Pathology
Asymptomatic large number of individuals are infected with no clinical symptoms
Intestinal disease by invading the intestinal mucosa
Hepatic disease by invading liver and causing amebic ulcers
Severe dysentery due to invasion of the intestinal mucosa by parasite
Entamoeba histolytica Diagnosis
Direct preps (look for motile trophs)
Stool concentrations (look for cysts)
Permanent stain is most important test
Entamoeba dispar
Noninvasive strain of E. histolytica
Cysts and trophozoites are indistinguishable from pathogenic E. histolytica
Does NOT ingest RBCs
Does NOT cause symptomatic disease
Entamoeba coli trophozoite
15-50 um
Vacuolated, “junky” cytoplasm with ingested bacteria and debris
Single nucleus with large, eccentric karyosome
Broad, short pseudopods with sluggish, nonprogressive motility
Entamoeba coli trophozoite
Entamoeba coli cyst
10-35 um
Coarsely granular, vacuolated cytoplasm
Up to 8 nuclei with eccentric karyosome
Chromatoidal bars (if present) have splintered stick-like ends
Occasionally have a glycogen mass
Entamoeba coli cyst
Entamoeba coli Pathology
Usually nonpathogenic
Entamoeba coli Diagnosis
Permanent stained smear (Trichome)
Always count the number of nuclei and look at karyosome
Entamoeba hartmanni trophozoite
4-12 um
Finely granular cystoplasm
Single nucleus with centrally located karyosome
Less motile than E. histolytica
Entamoeba hartmanni trophozoite
Entamoeba hartmanni cyst
5-10 um - measure organism to differentiate from E. histolytica
Finely granular cytoplasm
Up to four nuclei with centrally located karyosome
Chromatoidal bars with smooth ends, smaller and more numerous
Entamoeba hartmanni cyst
Entamoeba hartmanni Pathology
Nonpathogenic
Entamoeba hartmanni Diagnosis
Permanent stained smear - check size (very important)
Endolimax nana trophozoite
6-12 um
Single nucleus with large blot-like karyosome (ball in socket)
Cytoplasm may have small vacuoles with ingested debris or bacteria
Motility sluggish and nonprogressive with blunt, hyaline pseudopods
Endolimax nana trophozoite
Endolimax nana cyst
5-10 um (occasionally as large as 14 um)
Oval to round in shape
Up to four nuclei with no peripheral chromatin
Found in same specimen as trophozoite
Endolimax nana cyst
Endolimax nana Pathology
Nonpathogenic
Endolimax nana Diagnosis
Permanent stained smear (organism is very small)
Wet prep with four nuclear karyosomes will appear very refractile
Iodamoeba butschlii trophozoite
8-20 um, average 6-12 um
Cytoplasm granular with numerous vacuoles, ingested bacteria and debris
Single nucleus with large central or eccentric karyosome
Iodamoeba butschlii trophozoite
Iodamoeba butschlii cyst
5-20 um, average 10 um
Round or oval
Large glycogen vacuole in cytoplasm that stains with iodine
Single nucleus with large, irregular karyosome
Chromatin granules fan out around karyosome “basket” nucleus
Iodamoeba butschlii cyst
Iodamoeba butschlii Pathology
Nonpathogenic
Iodamoeba butschlii Diagnosis
Wet prep with iodine (detect cysts with glycogen)
Permanent stained smear (Trichome)
Entamoeba gingivalis trophozoite
5-20 um, average 10-15 um
Multiple pseudopods
Single nucleus with central karyosome
Finely granular cytoplasm
Ingested WBC (only species that does)
Entamoeba gingivalis trophozoite
Entamoeba gingivalis Pathology
Usually Nonpathogenic
Found in conjunction with periodontal disease
Entamoeba gingivalis Diagnosis
Permanent stained smear (Trichome)
Entamoeba gingivalis Treatment
Better oral hygiene
Entamoeba gingivalis cyst
No Cyst Stage
Blastocystis species
6-40 um
Membrane bound central body that takes up 90% of cell
Central body is surrounded by small, multiple nuclei
Blastocystis species
Blastocystis species Pathology
Etiologic agent of disease when present in large numbers and absence of other parasites, bacteria, or viruses. Diarrhea
Vomiting
Cramping
Abdominal pain
Blastocystis species Diagnosis
Permanent stained smear (Trichome) - central body area can stain various colors
MUST quantitate
ELISA methods
Fluorescent antibody techniques have been developed to aid in detection
Naegleria fowleri trophozoite
Two Forms
Ameboid
Flagellate
Naegleria fowleri Ameboid form
Only recognized form in humans
7-20 um
Elongated with board anterior end
Blunt pseudopodia with rapid and directional motility
Naegleria fowleri Flagellate form
Ameboid form changes to flagellate form when transferred from culture or teased from tissue into water at 27-37 C
Large, central karyosome
Cytoplasm is granular and contains vacuoles
Naegleria fowleri trophozoite
Naegleria fowleri cyst
7-10 um
Thick, double-walled
Single nucleus with central karyosome
Not found in human tissue
Present in nature and from agar cultures
Naegleria fowleri cyst
Naegleria fowleri Pathology
Primary amebic meningoencephalitis (PAM) seen in children and young adults and often fatal,
Trophozoites can look like WBCs on a counting chamber Look for motility
Naegleria fowleri Diagnosis
May have to reach by process of elimination
CSF results are:
Low glucose
High protein
High WBCs
Negative for bacteria
Solutions containing water that is source of infection
Acanthamoeba species trophozoite
30 um
Large distinct karyosome
Motility not evident
Spinelike pseudopods
No flagellate stage
Acanthamoeba species trophozoite
Acanthamoeba species cyst
15-20 um
Present in tissue
Single nucleus with large karyosome
Double-walled, with a slightly wrinkled fibrous outer layer (exocyst) and smooth inner wall (endocyst) that may appear polygonal, hexagonal, spherical, or star-shaped
Acanthamoeba species cyst
Acanthamoeba species Pathology
Granulomatous amebic encephalitis (GAE), more chronic than Naegleria
Associated with trauma or underlying disease
AIDs patients and immunocompromised
Primary infection is thought to be sinuses
Keratitis/corneal ulceration
Acanthamoeba species Diagnosis
GMS
PAS
Calcofluor white stains of tissue and look for characteristic cysts
