PROTOZOA Flashcards
➢ Most pathogenic amoeba in man
Entamoeba histolytica
➢ It is the only amoeba that has the potential of tissue invasion
Entamoeba histolytica
Endamoeba histolytica
Entamoeba histolytica
Amoeba dysenteriae
Entamoeba histolytica
Entamoeba dysenteriae/Endamoeba dysenteriae
Entamoeba histolytica
Entamoeba tetragena
Entamoeba histolytica
Large intestine of the host and other organs like liver, lungs, and the brain
Entamoeba histolytica
➢ Ingestion of contaminated food and water containing cysts
Entamoeba histolytica
➢ Direct contact to infected and uninfected persons (food handlers and housekeepers)
Entamoeba histolytica
➢ Faulty installation of water supple
Entamoeba histolytica
➢ Faulty sanitary disposal
Entamoeba histolytica
➢ Venereal transmission (sexually transmitted through fecal-oral contact)
Entamoeba histolytica
Precystic stage ➢ Transitional stage prior to the formation of cysts
Entamoeba histolytica
Precystic stage ➢ Colorless, round or oval, smaller than trophozoite but bigger than cyst
Entamoeba histolytica
Precystic stage ➢ Devoid of food inclusion and movement is sluggish with no progressive movement
Entamoeba histolytica
5-12 mcirons ; 12-60 u
Entamoeba histolytica
3-10 microns ; 10-16 u
Entamoeba histolytica
Finger-like and rapidly extruded
Entamoeba histolytica
Cysts Absent
Entamoeba histolytica
Active, progressive, and unidirectional motility
Entamoeba histolytica
Non-motile
Entamoeba histolytica
▪ No definite shape
Entamoeba histolytica
▪ Ectoplasm is thick, wide, refractile, and clearly differentiated from endoplasm which is finely granular that may contain ingested red blood cell BUT NO bacteria or foreign material
Entamoeba histolytica
▪ Karyosome is centrally located in the nucleus
Entamoeba histolytica
▪ Spherical with a definite outer cyst wall
Entamoeba histolytica
▪ Mature cyst has 4 nuclei (quadrinucleate)
Entamoeba histolytica
▪ Immature cyst has 1-2 nuclei
Entamoeba histolytica
▪ Motile or rounded
Entamoeba histolytica
▪ Nucleus not visible
Entamoeba histolytica
▪ RBCs are visible
Entamoeba histolytica
▪ Nuclei not visible
Entamoeba histolytica
▪ Chromatoid bar – refractile
Entamoeba histolytica
▪ Glycogen are refractile in young cysts
Entamoeba histolytica
Nucleus visible
Entamoeba histolytica
Nucleus visible
Entamoeba histolytica
chromatoid bodies seldomly seen
Entamoeba histolytica
glycogen in young cysts are visible
Entamoeba histolytica
Chromatoid matter Absent
Entamoeba histolytica
Rods with rounded ends (cigar/sausage-shaped)
Entamoeba histolytica
▪ Thermal death point at 50°C
Entamoeba histolytica
▪ Resistant to urine, grow best at anaerobic condition or under reduced oxygen tension
Entamoeba histolytica
▪ Optimum growth at 37°C at pH 7.0
Entamoeba histolytica
Factors Conducive to Invasion by Amoeba
➢ Temperature fluctuation in the host
➢ Abnormal secretory function
➢ Irritant foods
➢ Inadequate diet
➢ Inflammatory processes
✓ Asymptomatic in light infections (“luminal amebiasis”)
Entamoeba histolytica
✓ Abdominal tenderness
Entamoeba histolytica
✓ Diarrhea which may progress to dysentery in which there is passage of blood and mucus over a period of weeks
Entamoeba histolytica
✓ Constipation may be interspersed with diarrhea
Entamoeba histolytica
✓ Peritonitis
Entamoeba histolytica
✓ Dehydration
Entamoeba histolytica
➢ Acute Amebic colitis should be differentiated from bacillary dysentery caused by bacteria such as [?]
Shigella, Yersinia, Salmonella, and Escherichia coli
➢ Although stools may be grossly bloody, fever and significant elevated leukocyte count are less common in [?]
amebic colitis
must be ruled out before steroid therapy for inflammatory bowel disease is started because of the risk of developing toxic megacolon
➢ Amebic colitis
was named by Schaudinn in1903 because of its ability to lyse human tissues
Entamoeba histolytica
➢ Its invasive process is initiated when the trophozoite stage is able to penetrate through the mucus layer covering the colonic epithelium
Entamoeba histolytica
➢ Disease caused:
a) Amebiasis
b) Amebic hepatitis
c) Amebic colitis/dysenterY
d) Amebic liver abscess
e) Ameboma
Entamoeba histolytica
– clinically presents as gradual onset of abdominal pain and diarrhea with or without blood and mucus present in the stool
c) Amebic colitis/dysentery
– the most common extra-intestinal form of amebiasis
d) Amebic liver abscess
Incubation period: 4-5 days
Entamoeba histolytica
➢ Metacystic trophozoites invade the cecum and cecal mucosa
- Intestinal/Primary Amebiasis
➢ The trophozoites penetrate the cecal mucosa and epithelia by lytic digestion aided by amoeboid movement
- Intestinal/Primary Amebiasis
➢ Trophozoites burrow deeper with tendency to spread laterally by continuous lysis of cells until they reach the submucosa to form flaskshaped ulcers
- Intestinal/Primary Amebiasis
➢ Trophozoites demonstrated in every soft organ of the body
- Extra-intestinal/secondary/metastatic Amebiasis
➢ Trophozoites which reach the muscularis mucosa frequently erode and enter the lymphatics or walls of mesenteric venules on the floor of the ulcers to reach other organs
- Extra-intestinal/secondary/metastatic Amebiasis
- Extra-intestinal/secondary/metastatic Amebiasis:
a) Hepatic abscess
b) Pulmonary abscess
c) Cerebral amebiasis
d) Splenic abscess
e) Cutaneous abscess
➢ The standard method of parasitologic diagnosis is through microscopic detection of the trophozoites and cysts in stool specimen
Entamoeba histolytica
➢ The detection of E. histolytica trophozoites with ingested red blood cells is diagnostic of amebiasis
Entamoeba histolytica
➢ Ideally, a minimum of 3 stool specimens collected in different days should be examined
Entamoeba histolytica
- Direct Fecal Smear Examination and Permanently stained preparations (using trichrome stain)
Entamoeba histolytica
- Concentration Techniques
Entamoeba histolytica
- Purges saline by cathartic
Entamoeba histolytica
- Sigmoidoscopy material
Entamoeba histolytica
- Stool culture methods
Entamoeba histolytica
- Serological methods
Entamoeba histolytica
✓ For detection of trophozoites - fresh stool specimens (diarrheic/watery stool) should be examined within 30 minutes after collection
- Direct Fecal Smear Examination and Permanently stained preparations (using trichrome stain)
✓ Cyst stage – usually found in formed or semi-formed stool specimens
- Direct Fecal Smear Examination and Permanently stained preparations (using trichrome stain)
✓ Using the DFS with saline solution alone = one can observed the motility of the trophozoite
- Direct Fecal Smear Examination and Permanently stained preparations (using trichrome stain)
= Entamoeba spp. will stain blue, thus, differentiating them from white blood cells.
✓ Using saline + methylene blue
= the nucleus and karyosome can be observed so that E. histolytica can be differentiated from the non-pathogenic species (E. hartmanni, E. coli, E. nana)
✓ Using saline + iodine
- Concentration Techniques
FECT and MIFC are more sensitive than the DFS for detection of cysts.
✓ Balamuth’s medium
- Stool culture methods
✓ Rice egg saline
- Stool culture methods
✓ Locke egg serum
- Stool culture methods
– more sensitive than stool microscopy but is not routinely available
✓ Robinson’s and Inoki medium
✓ Complement fixation test
✓ Indirect Immunofluorescence Assay
✓ Gel diffusion
✓ ELISA
✓ Latex agglutination assay
✓ PCR – useful in differentiation of luminal infections (E. dispar) from invasive amoebiasis (E. histolytica)
- Serological methods
✓ Aspiration; biopsy
- For extra-intestinal amebiasis
✓ Molecular methods for differentiating between E. histolytica and E. dispar
- For extra-intestinal amebiasis
✓ Liver scan
- For extra-intestinal amebiasis
✓ Examination of aspirate (liver abscess)
- For extra-intestinal amebiasis
: most useful in patients with extraintestinal disease (i.e. amebic liver abscess) when organisms are not generally found on stool examination
❖ ANTIBODY DETECTION
: useful as an adjunct to microscopic diagnosis in detecting parasites and to distinguish between pathogenic and non-pathogenic infections (between E. histolytica and E. dispar infections
❖ ANTIGEN DETECTION
❖ Differentiation of E. histolytica and E. dispar is not possible by [?]. This can only be done by [?].
microscopy
PCR, ELISA, and isoenzyme analysis
❖ ELISA-based for stool is now commercially available showing a
sensitivity of 80% and specificity of 99%
❖ The use of [?] is limited by the requirement of sophisticated equipment
PCR
- Proper treatment of drinking water through filtration process and boiling of water
Entamoeba histolytica
- Proper disposal and treatment of human excreta
Entamoeba histolytica
- Proper installation and maintenance of potable water
Entamoeba histolytica
- Proper processing and safe handling and preparation of food
Entamoeba histolytica
- Health education and promotion (e.g. Practice of handwashing, proper use of latrines)
Entamoeba histolytica
- Use of iodine tablets to kill cysts
Entamoeba histolytica
- Uncooked vegetables should be scalded at 80’C for at least 30 seconds
Entamoeba histolytica
– 0.25 gram 4x a day for 10 days
✓ Entero viaform
– 0.5 gram 3x a day for 8 days
✓ Milibin
❖ Either of the above drugs should be combined with chloroquine or aralen to take care of tissue invaders
✓ Entero viaform
✓ Milibin
✓ Previous regiment is recommended, but in addition, this is given for first 3 days
emetine HCl
– 40-50 mg/kg body weight but not exceeding 2,000 mg in single dose repeated on the second day
✓ Tinidazole
– localized in the liver with or without extension to the lungs (drugs to be given should be amoebicidal)
For extra-intestinal Amebiasis
– 1mg/KBW but not exceeding 65 mg for 7-10 days; after a rest period of 2 weeks, the course is repeated
- Emetine HCl
– 4 tablets (250 mg salt) first dose; 2 tablets daily for 2 to 3 weeks
- Chloroquine or aralen
as in acute amebic dysentery
- Tinidazole
(Von Prowasek, 1912)
a. Entamoeba hartmanni
(Graasi 1879; Casagrandi & Barbagalio 1895)
b. Entamoeba coli
(Wenyon & O’Connor, 1917; Brug 1918)
c. Endolimax nana
(Von Prowasek, 1911; Dobell, 1911)
d. Iodamoeba butschlii
(Gros, 1849; Brumpt, 1913)
e. Entamoeba gingivalis
(Wenyon, 1909; Dobelli, 1918)
h. Dientamoeba fragilis
Entamoeba minuta
Entamoeba hartmanni
Entamoeba minutussima
Entamoeba hartmanni
Common name: “small race E. histolytica”
Entamoeba hartmanni
Amoeba coli
Entamoeba coli
Endamoeba hominis
Entamoeba coli
Laschia coli
Entamoeba coli
✓ Cross-eyed cyst
Endolimax nana
✓ Entamoeba nana
Endolimax nana
✓ Endolimax intestinalis
Endolimax nana
Common name: Smallest intestinal protozoan of man
Endolimax nana
Iodamoeba williamsi
Iodamoeba butschlii
Entamoeba williamsi
Iodamoeba butschlii
Entamoeba butschlii
Iodamoeba butschlii
Endolimax williamsi
Iodamoeba butschlii
Common name: Iodine cyst
Iodamoeba butschlii
Amoeba gingivalis
Entamoeba gingivalis
Amoeba buccalis
Entamoeba gingivalis
Entamoeba buccalis
Entamoeba gingivalis
Common parasite of pigs and monkeys
Entamoeba polecki
Intestinal tract of man
Entamoeba hartmanni
large intestine of man
Entamoeba coli
Cecum
Endolimax nana
Large intestine of man and swine
Iodamoeba butschlii
Found in the mouth, chiefly in the tartar of the teeth and gingival pocket
Entamoeba gingivalis
mucosal crypts of the cecum
Dientamoeba fragilis
Hand-to-mouth
Entamoeba coli
✓ Kissing or droplet spray
Entamoeba gingivalis
✓ Contaminated drinking utensils and dental utensils
Entamoeba gingivalis
➢ Resembles E. histolytica except in size (it is much smaller, and it does not ingest red blood cells)
Entamoeba hartmanni
➢ Resembles E. nana in size
Entamoeba hartmanni
- Trophozoite: 4-12 u
Entamoeba hartmanni
- Cyst: ✓ Mature cyst: 5-10 um with 4 nuclei (quadrinucleated)
Entamoeba hartmanni
- Cyst: ✓ Immature cyst: usually have chromatoidal bars
Entamoeba hartmanni
- Cyst: ➢ Chromatoidal bar: rice grain in shape
Entamoeba hartmanni
- Cyst: ➢ The nucleus and location of karyosome resembles E. coli
Entamoeba hartmanni
✓ Trophozoite does not ingest red blood cells
Entamoeba hartmanni
✓ Motility is sluggish
Entamoeba hartmanni
✓ Chromatoidal bodies: shorter with tapered ends often referred to as “rice grain shaped” or “thin fan like”
Entamoeba hartmanni
✓ Non-pathogenic or utmost causes only mild symptoms of enteritis
Entamoeba hartmanni
Nucleus: coarse, irregular peripheral chromatin; eccentric karyosome
Entamoeba coli
- Trophozoite: ✓ 15-20 um
Entamoeba coli
- Trophozoite: ✓ Coarse cytoplasm with many vacuoles and ingested bacteria
Entamoeba coli
- Trophozoite: ✓ Numerous nuclei (6-8 nuclei); however nucleus is not easily visualized
Entamoeba coli
- Trophozoite: ✓ Ectoplasm is granular and not easily differentiated from densely granular
Entamoeba coli
- Trophozoite: ✓ Short, blunt, and multiple pseudopods
Entamoeba coli
- Cyst: ✓ Round or spherical
Entamoeba coli
- Cyst: ✓ 10-35 um
Entamoeba coli
- Cyst: ✓ 1-8 nuclei
Entamoeba coli
- Cyst: ✓ Occasional chromatoidal bodies with splintered ends (splinterlike/filamentous/thread-like with granules/whiskbroom appearance)
Entamoeba coli
- Cyst: ✓ May have glycogen vacuole
Entamoeba coli
✓ No peripheral cromatin; large irregular karyosome
✓ Karyosome appears as a large round dot
✓ Spherical or subspherical
- Trophozoite: ✓ 2-12 um
Endolimax nana
- Trophozoite: ✓ Uninucleated
Endolimax nana
- Trophozoite: ✓ Finely granular, vacuolated cytoplasm (with narrow rim of ectoplasm)
Endolimax nana
- Trophozoite: ✓ Short pseudopod
Endolimax nana
- Cyst: ✓ 5-10 um
Endolimax nana
- Cyst: ✓ Round to oval; usually oval
Endolimax nana
- Cyst: ✓ 1-4 nucleus; possesses 4 nuclei when mature
Endolimax nana
- Cyst: ✓ Chromatoidal bodies are commashaped
Endolimax nana
✓ Spherical
Iodamoeba butschlii
✓ No peripheral chromatin
Iodamoeba butschlii
✓ Large karyosome surrounded by layer of small granules
Iodamoeba butschlii
✓ The karyosome is large, irregular, and rounded with a cluster of achromatic granules
Iodamoeba butschlii
- Trophozoite ✓ 8-20 um
Iodamoeba butschlii
- Trophozoite ✓ Coarsely granular cytoplasm with vacuoles and bacteria
Iodamoeba butschlii
- Trophozoite ✓ Blunt pseudopods (sluggishlyprogressively motility)
Iodamoeba butschlii
- Trophozoite ✓ Small with fairly active, progressive movement
Iodamoeba butschlii
- Trophozoite ✓ Ectoplasm is clear
Iodamoeba butschlii
- Cyst ✓ 5-20 um
Iodamoeba butschlii
- Cyst ✓ Ovoid
Iodamoeba butschlii
- Cyst ✓ Only one nucleus when mature
Iodamoeba butschlii
- Cyst ✓ Prominent glycogen vacuole (iodine-staining)
Iodamoeba butschlii
NO CYSTIC STAGE: exists only as a trophozoite and does not undergo encystation
Entamoeba gingivalis
- Trophozoite: ✓ Measures 535 um in diameter
Entamoeba gingivalis
- Trophozoite: ✓ Extrudes pseudopodia, similar to E. histolytica but does not exhibit progressive locomotion
Entamoeba gingivalis
- Trophozoite: ✓ Small and centrally located karyosome
Entamoeba gingivalis
▪ Morphologically identical to E. histolytica
Entamoeba dispar
▪ The only difference of E. dispar from E. histolytica is that it cannot ingest red blood cells
Entamoeba dispar
Originally described as amoeba, but is actually a flagellate with only the trophozoite stage known
Dientamoeba fragilis
It is now classified among the Trichomonads (despite the missing flagellum)
Dientamoeba fragilis
✓ Binucleated trophozoite
Dientamoeba fragilis
✓ Absence of the cyst stage
Dientamoeba fragilis
✓ Electron microscopic evidence of rudiments
Dientamoeba fragilis
✓ Resembles Trichomonads antigenically and ultrastructurally
Dientamoeba fragilis
✓ Small size, 2 nuclei
Dientamoeba fragilis
✓ Circular appearance at rest
Dientamoeba fragilis
✓ Rapid action of the multiple leaf-shaped pseudopods that gives a stellate appearance, and explosive disintegration in water
Dientamoeba fragilis
Host-Parasite Interaction: non-pathogenic, no symptoms, no need for treatment
Entamoeba coli
▪ Rarely to cause disease in humans
Entamoeba dispar
▪ Pathogenic to man
Dientamoeba fragilis
▪ Usually in coinfection with E. vermicularis
Dientamoeba fragilis
can be acquired while diving and swimming during hot weather in brackish or fresh water including swimming pools
Naegleria species (N. fowleri)
✓ Swimming in contaminated water
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
✓ Using inadequately disinfected contact lenses
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Portal of entry: broken or ulcerated skin or eye, lungs, genitourinary tract
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
- Trophozoite ✓ Size: 10-35 um
Naegleria species (N. fowleri)
- Trophozoite ✓ can assume limax form or become ameboflagellate
Naegleria species (N. fowleri)
- Trophozoite ✓ Has both amoeba and flagellated form
Naegleria species (N. fowleri)
: has a blunt pseudopodia and a vesicular nucleus with a large karyosome and sparse granules of peripheral chromatin
❖ Ameboid
: elongated and bears two equal and anteriorly located flagella
❖ Flagellated
✓ NOTE: when inside the host, Naegleria trophozoites do not exhibit the flagellated stage and cysts are not also formed; only the [?] is present inside the host
ameboid form Naegleria species (N. fowleri)
- Cyst ✓ Size: 7-10 um in diameter
Naegleria species (N. fowleri)
- Cyst ✓ Round
Naegleria species (N. fowleri)
- Cyst ✓ Cyst wall is smooth and double, with the outer wall perforated by 3 – 8 pores (ostioles)
Naegleria species (N. fowleri)
- Cyst ✓ Single nucleus
Naegleria species (N. fowleri)
- Cyst ✓ Spherical chromatoid bodies
Naegleria species (N. fowleri)
- Trophozoite ✓ 10-45 um
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
- Trophozoite ✓ Has single vesicular nucleus and also a large karyosome
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
- Cyst ✓ Uninucleated and double walled
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
- Cyst ✓ 16 um
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
➢ Major causative agent of Primary Amebic Meningoencephalitis (PAM)
➢ Primary Amebic Meningoencephalitis
− Usually fatal within a week of onset
➢ Primary Amebic Meningoencephalitis
− On autopsy examination (of mice and animals), the normal architecture of the brain particularly the olfactory lobes and cerebral cortex is completely destroyed. (“Brain-eating amoeba”)
➢ Primary Amebic Meningoencephalitis
− Causes purulent spinal fluid with motile amoeba
➢ Primary Amebic Meningoencephalitis
Ulcerative Acanthemoeba Keratitis in contact lens wearers
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Granulomatous Amebic Encephalitis
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Chronic Granulomatous lesions in the brain, skin, kidneys, liver, spleen, uterus, and prostate
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Microabscesses in the lungs and pancreas
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
− Causes keratitis, acquired from trauma and contact lens wear
Ulcerative Acanthemoeba Keratitis in contact lens wearers
− Characterized by severe ocular pain (invasion of cornea or interior of the eye)
Ulcerative Acanthemoeba Keratitis in contact lens wearers
− Chronic central nervous system infection; generally in debilitated or immunocompromised patients
Granulomatous Amebic Encephalitis
Chronic Granulomatous lesions in the
brain, skin, kidneys, liver, spleen, uterus, and prostate
Microabscesses in the
lungs and pancreas
Stained smears of culture material (demonstration of the trophozoites in CSF)
Naegleria species (N. fowleri)
Stained smears of culture material
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Histologic examination of brain
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Trophozoites and cysts in corneal scrapings
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
✓ Avoid swimming in stagnant water or thermal water
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
✓ Salination of water up to 0.7%
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Amphotericin B (given intravenously)
Acanthamoeba spp. (A. castellani, A. culbertsoni, A. hutchetti, A. polyphaga)
Finger-like
Entamoeba histolytica (Pathogenic)
Blunt and broader
Entamoeba coli (Non-Pathogenic)
Progressive and directional
Entamoeba histolytica (Pathogenic)
Sluggish, non-progressive, non-directional
Entamoeba coli (Non-Pathogenic)
Bull’s eye nucleus
Entamoeba histolytica (Pathogenic)
Eccentric karyosome
Entamoeba coli (Non-Pathogenic)
Clean-looking, with ingested RBCs
Entamoeba histolytica (Pathogenic)
Dirty-looking, heavily vacuolated due to ingested bacteria and food particles
Entamoeba coli (Non-Pathogenic)
Small race (nonpathogenic) ; Large race (pathogenic)
Entamoeba histolytica (Pathogenic)
Generally larger
Entamoeba coli (Non-Pathogenic)
Thin
Entamoeba histolytica (Pathogenic)
Thick
Entamoeba coli (Non-Pathogenic)
1-4 (infective)
Entamoeba histolytica (Pathogenic)
1-8 nuclei
Entamoeba coli (Non-Pathogenic)
Sausage-shaped
Entamoeba histolytica (Pathogenic)
Splinter/broomstick appearance
Entamoeba coli (Non-Pathogenic)
