Protozoans Flashcards
MOT and habitat or E. histolytica
MOT: ingestion of infective cyst
Habitat: Large intestine
The only pathogenic amoeba
E. histolytica
Number of nucleus of E. histolytica
Cyst: 4
Troph: 1
Described as clean-looking cytoplasm
E. histolytica trophozoite
Distribution of peripheral chromatin in E. histolytica
Evenly distributed
The only hematophagus amoeba
E. histolytica trophozoite
Appearance of chromatoidal bar of E. histolytica
cigar/sausage-shaped
Motility of E. histolytica trophozoite
Unidirectional, progressive
E. histolytica look-alikes
E. dispar
E. moshkovskii
E. bangladeshi
Virulence factor of E. histolytica
GalNac Lectin (for attachment), amoebapores (for holes), cysteine proteinases (for tissue disruption)
Used for differentiation of E. histolytica and E. dispar
ELISA
Drug of choice for E. histolytica for symptomatic px
Metronidazole
Drug of choice for E. histolytica for asymptomatic px
Diloxanide Furoate
Alternative drug for E. histolytica
Iodoquinol
Incubation period of E. histolytica
1-4 weeks
What are the commensal amebae?
E. coli, E. hartmanni, E. polecki, E. chattonii, E. nana, I. butschlii, E. gingivalis
Described as dirty-looking cytoplasm
E. coli troph
Appearance of chromatoidal bar of E. coli cyst
Splinter/broom stick shape
Motility of E. coli troph
Non-directional, non-progressive
Number of nuclei of E. coli
Cyst: 8
Troph: 1
Small race of E. histolytica
E. hartmanni
Number of nuclei of E. hartmanni
Cyst: 1-2
Troph: 1
Motility of E. hartmanni
Sluggish, non-progressive
Amoeba of pigs and monkeys
E. polecki
Number of nuclei of E. polecki
Cyst & Troph: 1
E. polecki is the most common parasite in ____
Papua New Guinea
Motility of E. polecki
Unidirectional, progressive, sluggish
Seen in apes and monkeys
E. chattoni
E. chattoni is morphologically similar to _____
E. polecki
Smallest intestinal amebae
E. nana
Number of nuclei of E. nana
Cyst: 4
Troph: 1
Has cross-eyed karyosome
E. nana
Appearance of chromatin in E. nana trophozoite
blunt and hyaline pseudopodia
Motility of E. nana troph
Unidirectional, non-progressive, sluggish
movement
Has a “basket of flowers” appearance
I. butschlii
Additional structure of I. butschlii
Glycogen vacuole
Amoeba that has no cyst stage
E. gingivalis
Also found in tartar, gingival pockets of teeth, and tonsillar crypts (of unhealthy mouths, but may also be in healthy mouths)
E. gingivalis
First amoeba in man
E. gingivalis
E. gingivalis is non-pathogenic, but can be seen in patients with _____
Pyorrhea alveolaris (gum infections)
The infective stage of free-living pathogenic amebae
Trophozoite
Found in inhabiting lakes, pools, tap water, air conditioning units, and heating units
Free-living pathogenic amebae
Target of free-living pathogenic amebae
CNS; brain tissue and CSF can be examined
Only Naegleria species that can infect humans
Naegleria fowleri
What does thermophilic mean?
thrive best in hot springs and other warm aquatic environments
Forms of N. fowleri
Cyst: spherical and single-walled
Troph: 1 nucleus, large & dense karyosome, cytoplasm is granular
Amoeboid form: limax-form (slug-like)
Ameboflagellate: 2 anterior flagella
Virulence factor of N. fowleri
Amebostomes (food cups)
Other pathogenic determinant of N. fowleri
▪ Secretion of lytic enzymes
▪ Membrane pore-forming proteins
▪ Induction of apoptosis
▪ Direct feeding of the ameba
Treatment and prevention of N. fowleri
Amphotericin B with Clotrimazole
Most common Acanthamoeba spp.
A. castellani
Entry of Acanthamoeba spp.
eyes, nasal passages to the lower respiratory tract, or ulcerated or broken skin
Acanthamoeba spp. is a possible reservoir host of medically important bacteria such as _____
Legionella spp., mycobacteria and gram-negative bacili (E. coli)
Trophozoite that as a “spring projection of the pseudopod”
Acanthamoeba spp.
Appearance of the walled cyst of Acanthamoeba spp.
Outer wall: wrinkled
Inner wall: polygonal
Acanthamoeba was first described in _____ as a/an _____
1974; opportunistic ocular surface pathogen
Symptoms: severe ocular pain, blurring vision, corneal ulceration with progressive corneal
infiltration
Acanthamoeba Keratitis
Acanthamoeba Keratitis can be mistaken for _____
Herpes keratitis (herpes has no ocular pain)
Caused by Acanthamoeba spp., usually occurs in immunocompromised hosts (chronically ill and debilitated patients, those on
immunosuppressive agents like chemotherapy and antirejection medications)
Granulomatous Amebic Encephalitis (GAE)
Incubation period of Granulomatous Amebic Encephalitis (GAE)
10 days
Signs and symptoms of Granulomatous Amebic Encephalitis (GAE)
destruction of brain tissue, meningeal irritation, fever, malaise, anorexia,
increased sleeping time, severe headache, mental status changes, epilepsy, and coma
Caused by Acanthamoeba spp., common in AIDS patients and which the parasite enters through skin
Cutaneous lesions
Cutaneous lesions can be distinguished by the presence of _____
Hard erythematous nodules or skin lesions
New species causing amebic meningoencephalitis; also causes Granulomatous Amebic Encephalitis (GAE)
Balamuthia mandrillaris
True or false. GAE is commonly diagnosed through the analysis of CSF
False. It is rarely demonstrated in CSF
Cyst and trophozoite appearance of B. mandrillaris
Cyst: wavy appearance
Troph: branching
Other free-living amoeba that causes amebic encephalitis
Sappinia diploidea
Hartmanella vermiformis
Flagellates that do not inhibit the large intestine
G. lamblia (small intestine), T. vaginalis (urogenital), T. tenax (mouth)
Flagellates that do not undergo encystation
Trichomons spp., D. fragilis
Non-commensal flagellates
G. lamblia, D. fragilis, T. vaginalis
Flagella is attached to the _____ found on the body of the parasite
blepharoplast
Giardia lamblia is also known as _____
G. duodenalis and G. intestinalis
How many cyst does it take for a person to be infected with G. lamblia?
8-10 cyst
What pH does G. lamblia prefer?
Alkaline = 7.8-8.2
Number of nuclei of G. lamblia
Cyst: 4
Trop: 2
Virulence factor of G. lamblia
Ventral sucking discs
Energy structure of G. lamblia
Median/parabasal bodies
Appearance of parabasal body of G. lamblia
Clawhammer shape
Incubation period of G. lamblia
1-4 weeks
Motility of G. lamblia
Falling Leaf Motility
Drug of choice for G. lamblia
Metronidazole
True or false. Chlorine can kill G. lamblia cyst
False. Iodine is used to disinfect water
A flagellate usually ingested with Enterobius and Ascaris
D. fragilis
Number of nuclei of D. fragilis
Troph: 2 (hence DIentamoeba)
Appearance of pseudopodia of D. fragilis troph
Angular
Fixation of D. fragilis
PVA or Schaudinn’s solution
Drug of choice of D. fragilis
Iodoquinol
Commensal parasite of the colon (specifically the cecal region)
Chilomastix mesnili
Shape of C. mesnili troph
Pyriform, pear-shaped
Shape of C. mesnili cyst
American lemon, nipple-shaped
With hyaline knob
C. mesnili cyst
Has cytostomal fibril that has a shepherd’s crook appearance
C. mesnili troph
Has a bird’s beak appearance
R. intestinalis cyst
Has a cleft-like cytostome
R. intestinalis
Motility of C. mesnili
Boring/Rotary/Corkscrew
Has a jerky motility
E. hominis
Number of nuclei of E. hominis
Cyst: 2-4
Troph: 1
Most prevalent nonviral sexually transmitted infection
Trichomoniasis (causative agent: T. vaginalis)
Shape of T. vaginalis troph
Pyriform, Pear-shaped
Motility of R. intestinalis
Jerky motility
Motility of T. vaginalis
Jerky tumbling
Has undulating membrane for movement
T. vaginalis
Also known as paraxostylar granules
Siderophil granules
Where is the undulating membrane found
Lateral portion
Effect of T. vaginalis to infants
Neonatal pneumonia
Incubation period of T. vaginalis
4-28 days
How is T. tenax diagnosed?
Swabbing tarter between teeth, gingival margin, or tonsillar crypts
Smallest among the Trichomonas species
T. tenax
Treatment of T. tenax
Metronidazole
Largest protozoan infecting man
B. coli
Function of micronucleus and macronucleus
micro: sexual reproduction
macro: asexual reproduction + vegetative function
Extrusive organelles in B. coli located beneath cell membrane
Mucocysts
The oral apparatus of B. coli
Cytostome
Function of contractile vacuoles in B. coli
Osmoregulation
Incubation period of B. coli
4-5 days
Shape of ulcers caused by B. coli
Flask-shaped (wider and rounded)
3 clinical manifestations of B. coli
Asymptomatic, Acute Cases (Fulminant Balantidiasis), Chronic cases