Protozoan Flashcards
(92 cards)
1
Q
Usual mode of transmission parasite
A
Ingestion
2
Q
Most members of the ameba inhabit which part/ organ
of the body?
A
Large intestine
3
Q
The small intestine is the site of
A
Encystation and
Excystation
4
Q
True or False: Lectin is used by pathogenic amebae to attach itself on the intestinal mucosa
A
True.
● by Entamoeba histolytica
5
Q
True or False: The cyst is the infective stage in the life cycles of all members of the amebae
A
False
● E. gingivalis is diagnosed through oral scraping -
trophozoite
6
Q
Which commensal amebae is known for its capacity to ingest leukocytes? Give the complete scientific name.
A
Entamoeba gingivalis
7
Q
Which amebae is known for causing PAM? Give the complete scientific name
A
Naegleria Fowleri: Free living amebae
8
Q
Locomotor apparatus of amebae
A
pseudopod. ○ “False feet”
9
Q
Amoeba have cytoplasm - Ectoplasmic extension wherein
where pseudopods are found,
A
outer ectoplasm
10
Q
one that would lead to infection.
Characterized by the most number of nuclei
A
Mature cyst
11
Q
True or false: Trophozoites are usually mononucleated.
A
True
12
Q
a reaction of the body to the agent.
A
Mucus
13
Q
True or false Red cells are indicative of
ulceration in the sample
It is also indicative that the parasite is
invasive.
A
True
14
Q
The enzyme that allows it to ulcerate
the intestine.
A
Cysteine proteinase
E. histolytica initiates response by increasing the mucous
production which ulcerates the intestinal mucosa through
its enzyme cysteine proteinase
15
Q
food of trophozoites. The moment you see one,
ulceration occurred already
A
RBCs
16
Q
trophozoites with ingested
RBCs. Very distinct in Entamoeba.
A
Hematophagous trophozoites -
17
Q
Ameba Generalized characteristic
A
Habitat: True with all the amoebae, they inhabit the Colon or large intestine
Infective Stage: True with all the amoebae, infective stage is cyst (only those that are encysting)
a. Except: E. gingivalis
Pathogenicity: Commensals (nonpathogenic)
a. Except: E. histolytica (causes amoebic
dysentery and ALA or amebic liver abscess
b. Free living amoebae are also non-
pathogenic
i. PAM: Naegleria fowleri
ii. GAM: Acanthamoeba
18
Q
maturity is determined whether
A
whether or
not cyst has attained max. number of nuclei, which
depends on the spp.
19
Q
One mature cyst can produce as many trophozoites as
A
the
number of nuclei it possesses (in mature stage)
20
Q
What are the INTESTINAL AMEBAE
A
E. histolytica (Pathogenic) E. dispar E. moshkovski E. harmanni Endolimax nana Iadoliman nana Iodamoabe butschlii
21
Q
3 Different types of Amoeba
A
Entamoeba
Endolimax
Iodamoeba
22
Q
Most invasive of the Entamoeba parasites
● Only member to cause colitis and liver abscess
A
ENTAMOEBA HISTOLYTICA
23
Q
Means of attachment of ENTAMOEBA HISTOLYTICA
A
Lectin
When it attaches, it creates a pore (amoebapore) para mabutas
24
Q
Multiplication means of ENTAMOEBA HISTOLYTICA
A
nuclear and cytoplasmic
divisions (binary fission)
25
Characteristics of Entamoeba Histolytica Trophozoite
Centrally located karyosome
Evenly distributed peripheral chromatin
Unidirectional (progressive) Pseudopod (fingerlike projection) motility
Extruded to one direction
Cystic wall is thin
Cytoplasm is clean looking
26
Characteristics of Entamoeba Histolytica Cyst
Spherical in shape
Centrally located karyosome
Evenly distributed peripheral chromatin
Chromatoidal bars or bodies are cigar-shaped
27
Other modes of transmission:
Venereal transmission through fecal-oral contact.
Direct colonic inoculation through contaminated
enema equipment.
28
A pseudopod-forming non-flagellated protozoan parasite.
Entamoeba Histolytica
29
The life cycle consists of two stages:
○ An infective cyst
○ An invasive trophozoite form
Entamoeba Histolytica
30
The quadrinucleate cyst is resistant to gastric acidity and
| desiccation, and can survive in a moist environment for several weeks
TRUE E. histolytica
31
Mechanism for virulence of E. histolytica
Contact-dependent cell killing
Cytophagocytosis - cell eater (consumes RBCs)
➢Lectin : Enzyme for the attachment of parasite to host
➢ Ameba pores : Formation of holes
➢ Cysteine Proteinase : Enzyme for tissue
destruction and spreading of infection
32
Contact-dependent cell killing
E. histolytica
33
E. histolytica cases may exist as Asymptomatic
Majority of cases present as asymptomatic infections with cysts being passed out in the stools (cyst carrier state).
34
Manifestations of E. histolytica infection:
1. Asymptomatic
2. Amebic Colitis
3. Ameboma
4. Amebic Liver Abscess
35
Manifestations of E. histolytica infection:
Most common presentation. It is the
inflammation of the large colon.
associated with a lot of bleeding and mucus
type of diarrhea here is watery and explosive = Amebic dysentery
Abdominal pain, blood and mucus in stool
Amebic Colitis
36
TRUE OR FALSE
Manifestations of E. histolytica infection:
Fever is not common and it occurs only in one third of patients.
TRUE
37
Manifestations of E. histolytica infection:
Children may develop
fulminant colitis
Severe bloody diarrhea, fever, abdominal
pain
38
Serious consequences of perforation (or ulceration) causes
Secondary bacterial peritonitis
39
When the amoeba invades the adjacent
intestinal organs, just like the liver, lungs, or any part of the peritoneal cavity. They may form cystic mass.
Mass-like lesion with abdominal pain and history of dysentery
Can be mistaken as a carcinoma (tumor/cancer)
May be asymptomatic
Occurs in less than 1% of intestinal
infections
Ameboma
40
The most common organ that is invaded
The abscess appearance of this amoebic is very characteristic. It’s characterized by anchovy-sauce just like in sardines (tomato).
Amebic Liver Abscess
41
Most common extraintestinal form of amebiasis
Amebic Liver Abscess
42
Usually presents with fever and RU quadrant pain. (Book) Several studies have shown these two as the most frequent complaints, particularly in acute cases (<2 weeks duration). Hepatomegaly is present in 50% of cases.
Amebic Liver Abscess
43
DIAGNOSIS OF E. HISTOLYTICA:
The standard method of parasitological diagnosis is microscopic detection of the trophozoites and cysts in stool specimens. Ideally, a minimum of ____ stool specimens collected on different days should be examined.
3
44
diagnosis of E. histolytica
DFS
```
Concentration technique (FECT - Formalin Ether/Ethyl Acetate Concentration
Test and Merthiolate Iodine Formalin Concentration Test (MIFC))
```
PCR (Polymerase Chain Reaction)
Serological tests (ELISA): Enzyme-linked immunosorbent assay
Ultrasound, CT scan, MRI
45
Molecular testing done to distinguish E. histolytica from E. dispar
PCR (Polymerase Chain Reaction)
46
Diagnostic testing for Amebic Liver Abscess
Serological tests (ELISA): Enzyme-linked immunosorbent assay
47
Non-invasive and sensitive methods in early
| detection of ALA.
Ultrasound, CT scan, MRI
48
Generic drug that is used for most protozoans including flagellates and ciliates
Drug of choice for trophozoites (invasive amebiasis, colitis, amebic dysentery, liver abscess, ameboma)
TROPHOZOITE
Metronidazole
49
Drug of choice for healthy carriers/asymptomatic cyst
passers (people who are reservoir for the infection)
○ (Book) Also given after a course of metronidazole for invasive amebiasis
CYST
Diloxanide furoate
50
EPIDEMIOLOGY OF AMEBVIASIS
Amebiasis: 1-5% worldwide
| Particular in trophics
51
3rd most important parasite
malaria, schistosomiasis, e. histolytica (amebiasis)
52
Morphologically similar to E. histolytica, but differs on their ribosomal RNA and DNA
E.DISPAR AND E. MOSHKOVSKII
53
E. moshkovskii differs biochemically and genetically because
Osmotolerant - able to grow at room temperature
54
Cosmopolitan in distribution
| More common than other human amebae
ENTAMOEBA COLI
55
Most common amebic organism that can be identified in stools of patients.
ENTAMOEBA COLI
56
Characteristics of E. coli cyst
```
Large amoeba (10-35)
Max of 8 nuclei
Nuclei looks like pocket of coins
More granular cytoplasm
Splinter-like chromatoidal bodies
RBC is not present
```
57
Nuclei looks like pocket of coins
E. coli cyst
58
Characteristics of E. coli trophozoite
Trophozoites measure 15 to 50 μm in diameter
More vacuolated or granular endoplasm with bacteria and debris but no red blood cells
Narrower, less-differentiated ectoplasm
Broader and blunter pseudopodia used more for
feeding than locomotion
More sluggish, undirected movements
Thicker, irregular peripheral chromatin with a large, eccentric karyosome in the nucleus
59
Appearance is relatively similar to E. histolytica apart from its smaller size.
Diminutive version of E. histolytica
Referred to as the “small race” of E. histolytica, it is differentiated primarily on the basis of the size.
ENTAMOEBA HARTMANNI
60
E. hartmanni cyst characteristics
Size 4-10
Quadrinucleated
Rod-shaped chromatic material with rounded or squared ends
61
Found in the intestines of pigs and monkeys
Rarely infects humans
Entamoeba Polecki
62
Entamoeba Polecki trophozoite characteristics
Motility is sluggish
A small karyosome is centrally located in the nucleus.
UNINUCLEATED
chromatoidal bars are frequently angular or pointed.
Chromatoidal body looks like a chinese character
○ Criss-crossing of chromatoidal body???
In stained fecal smears, the nuclear membrane and
karyosome are very prominent.
63
Occurs with the same frequency as Entamoeba coli
Endolimax nana
64
Endolimax nana trophozoite characteristics
small (5-12)
Motility: sluggish
Blunt hyaline pseudopodia
Nucleus has a large, irregular karyosome
Food vacuoles found in the cytoplasm may contain
bacteria
65
Endolimax nana cyst characteristics
same size as trophozoite
Quadrinucleated when mature
Often referred to as a cross-eyed cyst
Karyosome is very big, stained red and is
very prominent
66
Ameba of swine (pigs)
IODAMOEBA BUTSCHLII
67
IODAMOEBA BUTSCHLII TROPHOZOITES characteristics
Large, vesicular nucleus (uninucleated) with a large central karyosome; with achromatic granules
“Basket of Flowers”
No peripheral chromatin granules on the nuclear
membrane
9-14 um average diameter (ranging from 4 to 20 um)
68
IODAMOEBA BUTSCHLII cyst characteristics
9 to 10 um in diameter
Uninucleated with large glycogen body which stains
dark brown with iodine
Large glycogen vacuole → especially in the cystic stage
It’s important to look at the cyst because you’ll see there the large glycogen vacuole
69
Best demonstrated with iodine stain on the wet mount like your lugol's iodine and MIF
IODAMOEBA BUTSCHLII
70
Found in moutgh
Trophozoite measures 10 to 20 um
● It moves quickly, has numerous blunt pseudopodia
● Food vacuoles that contain cellular debris (mostly
leukocytes, which is characteristics of this species) and
bacteria are numerous
● Lives on the surface of gum and teeth, in gum pockets and
sometimes in the tonsillar crypts
● They are abundant in cases of oral disease
● It has no cyst stage
● Transmission is most probably direct: through kissing,
droplet spray, or by sharing utensils
ENTAMOEBA GINGIVALIS
71
MOT of E. gingivalis
Direct contact : Kissing or droplets spray
72
What are the Free-living pathogenic amebae
○ Acanthamoeba
○ Balamuthia
○ Naegleria
73
These pathogenic amoeba are found free living in
water bodies like lakes, ponds, tapwaters and even in the air conditioned units that are not cleaned or maintained regularly
Free-living pathogenic amebae
○ Acanthamoeba
○ Balamuthia
○ Naegleria
74
The Only free-living pathogenic ameba reported to cause disease in humans.
Naegleria Fowleri
75
Three stages of Naegleria Fowleri
Feeding trophozoite stage
Dormant cyst stage
Transitional flagellate stage
76
Naegleria fowleri trophozoites characteristics
Ameboid Trophozoite:
■ Cytoplasm: granular and contains many vacuoles.
■ Nucleus: single and large.
■ Dense karyosome.
■ Lacks peripheral chromatin.
77
form of Naegleria fowleri produced when conditions are not favorable.
Dormant cyst stage
78
form of Naegleria fowleri
that are Thermophilic organisms thriving best in hot
springs and warm aquatic environment.
Transitional flagellate stage
79
Means of transmission of Naegleria fowleri
Entry into the body: Olfactory Epithelium, Respiratory
| Tract, Skin and Sinuses
80
Causes Primary Amebic
| Meningoencephalitis (PAM)
Naegleria Fowleri
81
Diagnostically can find the trophozoite in the CSF
Naegleria Fowleri
82
meningitis symptoms: high
| grade fever, seizures, headache
Primary Amebic Meningoencephalities (PAM)
83
MOT of ACANTHAMOEBA SPP.
through eyes
Nasal passages to lower respiratory tract
Ulcerated or broken skin
84
highly resilient which transforms when environmental conditions are not favorable
ACANTHAMOEBA SPP. cyst
85
Free-living pathogenic ameba that causes Granulomatous Amebic Encephalitis (chronic; slow in progression) & Amebic Keratitis
ACANTHAMOEBA SPP.
86
very difficult to differentiate this from TB encephalitis, moreso TB is more common than this Amebic Encephalitis.
Granulomatous Amebic Encephalities
87
Signs and symptoms: generally related to destruction of brain tissue and the associated meningeal irritation.
Systemic manifestations early in the course include fever, malaise, and anorexia
Neurologic symptoms may include increased sleeping time, severe headache, mental status changes, epilepsy, and coma.
Granulomatous Amebic Encephalities
88
It is a ubiquitous ameba that has many reservoirs in nature like other animals.
ACANTHAMOEBA SPP.
89
Can cause Amebic keratitis or the infection of cornea
ACANTHAMOEBA SPP.
90
Both the trophozoite and the cystic stage can actually be the mode of infection, and they enter the human in various ways.
ACANTHAMOEBA SPP.
91
ACANTHAMOEBA SPP. trophozoite characteristic
thorn-like appendage called acanthopodia
92
Diagnosis of GAE
Biopsy
Corneal Scarpings
Culture
Molecular methods
