Protozoans Flashcards
Diagnosis for N.fowleri
- Presence of trophozoites in CSF
- PCR
- Culture
Pseudopod-forming and non-flagellated protozoan parasite:
Entamoeba histolytica
Small, spiny filaments for locomotion
Acanthopodia
Protozoans belong to this Phylum and Kingdom
Phylum - Protozoa
Kingdom - Protista
Distinguished from E.histolytica by PCR
Entamoeba dispar
E.coli or E.histolytica
Splinter-like chromatoidal bodies, iodine staining reveals dark-staining, perinuclear masses, which are actually glycogen
E.coli
Disease caused by Naegleria fowleri
Primary Amoebic Meningoencephalitis (PAM)
E.coli or E.histolytica
more sluggish, unidirected movements
E.coli
They are motile and cannot encyst if excreted from the vody:
E. histolytica trophozoites
E.coli or E.histolytica
Broader and blunter pseudopodia used more for feeding than locomotion
E.coli
2 forms of N.fowleri trophozoite:
- Ameboid (found in humans)
- Ameboflagellates (jerky motility)
True or False
Cyst of N.fowleri is multi-nucleated with rounded chromatoidal bars
False
They are uninucleated
Cyst and Trophozoite of this parasite possess 2 nuclei
Sappinia spp.
Treatment for Entamoeba histolytica:
Metronidazole
Reproduction of Amoeba:
Binary fission
The cytoplasm of this trophozoite has bacteria and undigested food
Entamoeba coli trophozoite
Treatment for Acanthamoeba keratitis (AK)
- Surgical excision of the infected area
- Deep Lamellar Keratectomy: superficial
- Clotrimazole combined with Pentamidine, Isethionate, and Neosporin
Classified as free-livinf amoeba (rarely infect humans)
Entamoeba moshkovskii
Brain-eating amoeba
Naegleria fowleri
Vegetative forms of N.fowleri
- Ameba (trophozoite form)
- Flagellate (swimming form)
They are unicellular organisms without tissues and organs
Protozoans
Thermophilic organism (up to 30 deg celsius)
Naegleria fowleri
Locomotory organelle which also help in food capturing:
Pseudopodia
Naegleria fowleri multiplies through:
Promitosis (intracellular mitosis)
Parasite isolated from soil and dust
Balamuthia mandrillaris
Has iodine cyst and a large glycogen vacuole/body which stains deeply with iodine, uninucleated
Iodamoeba butschlii
Free-living Pathogenic Amoeba:
*Naegleria fowleri
*Acanthamoeba spp.
Protozoa came from these Greek words
Protos - first
Zoon - animals
True or false:
Trophozoites of E. histolytica are resistant acidic pH
False - Cysts are resistant to acidic pH, not Trophozoites
Infective stage of Acanthamoeba spp.
Trophozoite
“Thorn-like” appendages
Acanthopodia
Most pathogenic Amoeba:
Entamoeba histolytica
E. coli or E. histolytica:
More vacuolated or granular endoplasm with BACTERIA and DEBRIS, but NO RED BLOOD CELLS
E. coli
Formed during the initial stage of Encystment and appear as an AMORPHOUS, DISCONTINUOUS LAYER
Ectocyst
E.coli or E.histolytica
Thicker, irregular peripheral chromatin with a large, eccentric karyosome in the nucleus
E.coli
True or false:
E. histolytica has centrally located karyosome
True
True or False:
Entamoeba dispar is the only member of the family “Entamoebidae” to cause colitis
False - Entamoeba histolytica is the only member of the family “Entamoebidae” to cause colitis
True or False
E.coli is smaller than E.histolytica
False
E.coli (10-35 um) is larger than E. histolytica (10-20 um)
Bacillary Dysentery or Amebic Dysentery
Prodromal fever and malaise common
Bacillary Dysentery
True or False
The trophozoite of N.fowleri has granular cytoplasm and contains many vacuoles
True
E.coli or E.histolytica
Narrower, less-differentioated ectoplasm
E.coli
They are minute, generally microscopic and eukaryotic organisms:
Protozoans
Parasites under Phylum Apicomplexa:
Sporozoa:
* Plasmodium spp.
* Babesia spp.
They can be free-living, parasitic, or symbiotic in nature.
Protozoans
True or False
Cyst of N.fowleri does not form in human tissue
True
Activated T-cells kill E.histolytica by:
- directly lysing trophozoites
- producing cytokines (activate macrophages and neutrophils/eosinophils
- providing helper effect for B-cell antibody production
Smallest protozoa
Endolimax nana
True or False
Trophozoite of N.fowleri cannot turn into temporary non-feeding flagellated forms
False
They CAN turn into temporary non-feeding flagellated forms
Inner granular portion of the Cytoplasm body
Endoplasm
This commensal amoeba exists in TROPHOZOITE STAGE ONLY
Entamoeba gingivalis
True or False
Cyst of N.fowleri have a smooth, double-layered wall
False
Cyst of N.fowleri is SINGLE-LAYERED
Protoplasm is differentiated into:
Ectoplasm and Endoplasm
Symptoms:
* severe ocular pain and blurring of vision
* Corneal ulceration with progressive corneal infiltration
* may lead to hypopyon formation
* Progression of infection may cause scleritis and iritis, and may
ultimately lead to vision loss
Acanthamoeba Keratitis (AK)
This trophozoites has a centrally located karyosome and long and finger-like pseudopodia
Entamoeba histolytica trophozoite
Mode of Transmission for Acanthamoeba spp.
Eye, nasal passages, ulcerated or broken skin
Considered a true pathogen
Naegleria fowleri
3 stages of N.fowleri
- Cyst stage
- Trophozoite stage
- Flagellated stage
They may adopt in a different host and transfer themselves passively in the cystic stage
Monogenetic Protozoa
Characterized by an active trophozoite stage with characteristic prominent “Thorn-like” appendages
Acanthamoeba spp. (A.castellani)
Size of E. histolytica cyst
10-20 um
True or False:
Protozoans generally multiply sexually.
False - they generally multiply ASEXUALLY
Bacillary Dysentery or Amebic Dysentery
Bloody diarrhea
Amebic Dysentery
Has 3 layered cystic walls (visible through electron microscope)
Balamuthia mandrillaris
Bacillary Dysentery or Amebic Dysentery
Seldom epidemic
Amebic Dysentery
This parasite’s cyst has 1-8 nuclei and has a Broomstick-like Chromatoidal bodies
Entamoeba coli
Their cysts are quadrinucleated with coarse cytoplasm; immature cyst has chromatoidal bars
Entamoeba hartmanni
2 parts of the Cytoplasm body:
Ectoplasm and Endoplasm
Mode of reproduction of Protozoans:
Binary or Multiple fission, Budding
Mode of transmission for Entamoeba histolytica:
Ingestion of food/water with cyst
Examples of Digenetic Protozoa:
Leishmania, Plasmodium, and Trypanosoma spp. (LPT)
Specimen for Acanthamoeba spp.
- Discharges
- Exudates
- Tissue secretions
- Epithelial biopsy
- Corneal scrapings
Isolated in the feces of many animals, including mammals and reptiles
Sappinia spp.
Morphologically similar with E.histolytica but with a different genome
Entamoeba dispar
Bacillary Dysentery or Amebic Dysentery
Charcot-leyden crystals present
Amebic Dysentery
Feeding and vegetative stage of Entamoeba histolytica:
Trophozoites
CSF: ELEVATED WBC WITH NEUTROPHILIC PREDOMINANCE; HIGH PROTEIN AND LOW GLUCOSE
Primary Amoebic Meningoencephalitis (PAM)
Pathogenesis of Acanthamoeba spp.
- Granulomatous Amebic Encephalitis (GAE)
- Acanthamoeba Keratitis (AK)
Morphologically similar to E.histolytica and E.dispar
Entamoeba moshkovskii
Bacillary Dysentery or Amebic Dysentery
Fishy odor stool
Amebic Dysentery
Treatment for N.fowleri
Amphotericin B in combination with Clotrimazole
2 stages of E. histolytica:
Cyst stage (infective) and Trophozoite stage
Infective stage of Balamuthia
Trophozoite
Cytoplasm: ingests RBC
E. histolytica trophozoite
Bacillary Dysentery or Amebic Dysentery
Spontaneous recovery, no relapse
Bacillary Dysentery
Has rounded ends, sausage-shaped chromatoidal bodies
E. histolytica cyst
Resilient and difficult to treat
Acanthamoeba spp. cyst
Distinguished from E.histolytica by cyst
Entamoeba polecki
This trophozoite has progressive and directional locomotion
Entamoeba histolytica trophozoite
This trophozoite has non-progressive and sluggish locomotion
Entamoeba coli trophozoite
How many layers of B.mandrillaris cyst are visible through light microscopy?
2 layers
They require TWO (2) hosts to complete their life cycle
Digenetic Protozoa
Survive in contact lens cleaning solutions
Acanthamoeba spp. (A.castellani)
Large irregular mass of chromatin occupying almost 1/2 diamter of karyosome
Endolimax nana
Specimen of choice for E. histolytica:
Stool
Formed - cyst
Diarrheic - trophozoites
Bacillary Dysentery or Amebic Dysentery
Lasts for weeks, dysentery returns
Amebic Dysentery
Cyst has 4 nuclei concentrated at one end “cross-eyed cyst”
Endolimax nana
Pathogenic Intestinal Amoeba:
Entamoeba histolytica
Singel nucleus is found in the:
Endoplasm or Ectoplasm
Endoplasm
True or False:
Parasitic protozoa perform asexual reproduction only in one host
False - Parasitic protozoa perform ASEXUAL and SEXUAL reproduction in DIFFERENT HOSTS (alternation of generation)
Morphologically similar to E.histolytica but smaller and has no RBC inclusion
Entamoeba hartmanni
Bacillary Dysentery or Amebic Dysentery
Tenesmus common
Bacillary Dysentery
Produced when conditions are not favorable
Dormant cyst (Naegleria fowleri)
This parasite’s cyst has 1-4 nuclei and has Sausage/Cigar-shaped Chromatoidal bodies with rounded ends
Entamoeba histolytica
They require ONE host to complete their life cycle:
Monogenetic Protozoa
Acanthopodia spp. replicate by:
Mitosis
It is pseudopodia-long and finger-like
E. histolytica trophpzoite
Single large nucleus with a centrally-located, densely staining nucleolus
Acanthamoeba spp. trophozoite
Parasite of pigs and monkeys; rarely infect humans
Entamoeba polecki
Mode of transmission for N.fowleri
Nasal, and Broken skin
Ubiquitous, free-living amoeba
Acanthamoeba spp.
Has progressive and directional movement:
E. histolytica trophozoite
Bacillary Dysentery or Amebic Dysentery
Odorless stool
Bacillary Dysentery
Bacillary Dysentery or Amebic Dysentery
Watery, bloody diarrhea
Bacillary Dysentery
Cysts are consistently uninucleated
Entamoeba polecki
This usually occurs to protect the cell from the unfavourable conditions, and it also helps in dispersal
Encystment
Non-feeding and infective stage of Entamoeba histolytica:
Cyst
They are non-motile and resistant to acidic pH
E. histolytica cyst
Double-walled, consisting of an Ectocyst and an Endocyst
Acanthamoeba spp. cyst
True or False
Trophozoite of Balamuthia mandrillaris has finger-like pseudopodia
True
Most common Acanthamoeba spp.
Acanthamoeba castellani
Bacillary Dysentery or Amebic Dysentery
May be epidemic
Bacillary Dysentery
Parasites under Phylum Sarcomastigophora:
Sarcodina:
* Amoeba
* Commensal Amoeba
Mastigophora:
* Atrial Flagellates
* Non Pathogenic Flagellates
* Blood and Tissue Flagellates
Mode of transmission for N. fowleri
Oral and intranasal routes while swimming in contaminated lakes, pools, rivers
Associated with the use of improperly disinfected soft contact lenses
Acanthamoeba Keratitis
True or False
Single reported case of infection with Sappinia pedata in a human was identified in Brazil
False
It was identified in Texas.
The cytoplasm of this trophozoite contains ingested RBCs
Entamoeba histolytica trophozoite
Size of E. histolytica trophozoite:
12 - 60 um
How many nuclei are there in the cyst of E. histolytica?
1-4 nuclei
Has a fine granular texture, and is uniformly thicker
Endocyst
Bacillary Dysentery or Amebic Dysentery
Acute onset
Bacillary Dysentery
This commensal Amoeba is transmitted person-to-person orally by kissing or fomites and it resides in the oral cavity
Entamoeba gingivalis
True or False:
Body of amoeba is with pellicle, and has a fixed shape
False - Body of Amoeba is WITHOUT PELLICLE, and has NO FIXED SHAPE
Only member of the family “Entamoebidae” to cause colitis:
Entamoeba histolytica
Large endosome, finely granulated cytoplasm
Acanthamoeba spp. trophozoite
Systemic manifestations early in the course include fever, malaise, andanorexia
Granulomatous Amebic Encephalitis (GAE)
Bacillary Dysentery or Amebic Dysentery
No charcot-leyden crystals
Bacillary Dysentery
Pathogenesis of E. histolytica
Amoebic dysentery/diarrhea containing blood and mucus
Non-pathogenic (commensal) Amoeba: (8)
*Entamoeba coli
*Entamoeba dispar
*Emtamoeba hartmanni
*Entamoeba polecki
*Entamoeba gingivalis
*Entamoeba moshkovskii
*Endolimax nana
*Iodamoeba bütschlii
Neurologic symptoms may include increased sleeping time, severe
headache, mental status changes, epilepsy, and coma
Granulomatous Amebic Encephalitis (GAE)
Able to survive at temperature range of 0-41 deg Celsius and is Osmotolerant
Entamoeba moshkovskii
True or False:
Reproduction of Protozoans may switch to sexual method or undergo cystic change to its host
True
usually occurs in immunocompromised host, generally related to destruction of brain tissue and the associated meningeal irritation
Granulomatous Amebic Encephalitis (GAE)
Parasite under Phylum Ciliophora:
Ciliata:
* Balantidium coli
Formation of flask-shaped ulcers
Amoebic dysentery (E. histolytica)
This trophozoite has eccentric nucleus and short, blunt pseudopodia
Entamoeba coli trophozoite
Causative agent of Primary Amoebic Meningoencephalitis (PAM)
Naeleria fowleri
Used for locomotive, for protection, and sensory purposes:
Ectoplasm
Locomotory organelles of Protozoa;
Flagella, Cilia, or Pseudopodia
“Small race” Ameoba
Entamoeba hartmanni
Free living or endoparasite:
Amoebas
Bacillary Dysentery or Amebic Dysentery
Gradual onset
Amebic Dysentery
Outer hyaline portion of the Cytoplasm body:
Ectoplasm
For nutritive and reproductive function:
Endoplasm