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MicroBio - Parasitology > Protozoa > Flashcards

Protozoa Flashcards

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1
Q

Cytoplasm contains

A

Ultramicrospcopic organelles

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2
Q

Protozoan nuclei:

A

Macronucelus

Micronuclues

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3
Q

Long hair-like structures; characteristic of mastigophorans

A

Flagella

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4
Q

Short hair-like structures; surrounds the organism, often in rows

A

Cilia

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5
Q

Common life stage:

A

Trophozoit

Cyst

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6
Q

Dormant stages, produced by many of the protozoans
Capable of protection: During adverse environmental conditions
Generally non-feeding
Non-motile
Size: Usually smaller than trophozoites of the same species

A

Cyst

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7
Q

Metabolic stage
Active, vegetative; feeding
Capable of movement: Motility dependent on organelles
Size: Varied, ultramicroscopic to 1.0 mm
Shape: Varied, mostly subspherical; dependent upon cytoplasmic structure and organelles

A

Trophozoite

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8
Q

Cyst wall: Secreted scleroproteins (keratin-like or elastin-like albuminoids)

Glycogen vacuoles: Food storage vacuoles

Chromatoidal bodies: Composed of RNA-protein complex; crystalline; resemble viral particles; 0.3 to 1.0μm helical bodies; aggregate in crystalline array and become visible; serve as storage for Ribosomes

A

Cyst

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9
Q

Disease characteristics
Intestinal amebiasis
Non-dysenteric colitis
Amebic dysentery

A

Entamoeba histolytica

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10
Q

Tissue lysing enzymes: Cytolysins; proteolytic secretions

Ulceration: Penetration of the mucosal crypts; extension into submucosa forming FLASK-SHAPED lesions

Amebomas (amebic granulomas): Granulation tissues; tumors

A

Entamoeba histolytica

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11
Q

Collect three specimens: One every other day
Avoid contact with water or urine
Liquid stools: Examine within 30 minutes
Perform direct examination in physiological saline and Lugol’s iodine
Perform concentration technique

A

Lab ID:

Feces

Entamoeba histolytica

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12
Q

Charcot-Leyden crystals: Formed from the breakdown of eosinophilic blood cells; indication of bleeding or inflammation of the intestinal mucosa

A

Microspcopic examination

Entamoeba histolytica

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13
Q

Trophozoite form
Cytoplasm: Clean
Appearance: Finely granular
Inclusions: Occasional RBCs (in case of dysentery); few bacteria or debris in vacuoles

A

Lab ID:

Entamoeba histolytica

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14
Q

Nucleus:
Centrally located endosome

‘bulls eye’

A

Entamoeba histolytica

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15
Q

Worldwide distribution, but mostly in tropical areas with poor sanitation

Acquired through ingesting the quadrinucleate cyst on contaminated food or water.

A

Entamoeba histolytica

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16
Q

Causes amoebic dysentery. 10% extraintestinal invasion to liver, lungs, brain.

A

Entamoeba histolytica

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17
Q

Causes flask shaped ulcers

A

Entamoeba histolytica

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18
Q

Trophozoites often contain ingested RBCs (diagnostic), but need molecular testing to be sure.

A

Entamoeba histolytica

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19
Q

Often confused with Entamoeba histolytica

“Nonpathogenic”

A

Entamoeba Coli

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20
Q

Nucleus: Vesicular, dispersed type
Number: One
Peripheral chromatin: Coarse granules; irregular size and distribution
Karyosome: Small (larger than Entamoeba histolytica); usually eccentric

A

Entameoba coli

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21
Q

Cytoplasm
Appearance: Vacuolated, coarsely granular
Inclusions: Yeast (may include spores of Sphaerita), molds, bacteria, etc.
Motility: Sluggish; non-directional with blunt, poorly defined, pseudopodia

A

Entamoeba coli

Trophozoite form

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22
Q

Mature cysts of ___ ___ characteristically have eight nuclei, rarely 16.

A

Entamoeba coli

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23
Q

Nonpathogenic commensal.

Worldwide distribution

An indicator of poor hygiene.

A

Entamoeba coli

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24
Q

Cysts will have 5 or more nuclei with ECCENTRIC ENDOSOME

A

Entamoeba coli

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25
Disease: Giardiasis
Giardia Lamblia
26
Incidence: Higher in children and young adults ``` Symptoms: Irritation to the intestinal mucosa Recurrent diarrhea (dehydration) ```
Giardia lamblia
27
Malabsorption Large numbers of parasites attached to the intestinal mucosa: Block absorption Inhibits fat absorption: Mechanical and chemical interference Excludes absorption of fat soluble vitamins: Primarily VITAMIN A
Giardia lamblia
28
Habitat: Small intestine Reservoir hosts: Beavers, small mammals, herbivores Infective form: Mature quadrinucleated cyst Mode of infection: Ingestion (may come from springs, creeks, or swimming pools
Giardia lamblia
29
Lab ID: Feces and duodenal contents Serological techniques, EIA, ELISA for antigen Flourescent for presence in feces
Giardia lamblia
30
Trophozoite form: "wry little face“ Size: 9 to 20μm Shape: Pear-shaped Dorsal surface: Convex Ventral surface: Concave with sucking disc Nucleus: Two (bi-symmetrical arrangement)
Giardia lamblia
31
Trophozoite form: "wry little face“ Cytoplasm Flagella: 8 Anterior: 2 (crossing at the midline) Ventral: 4 (2 just behind the ventral notch; 2 behind the median bodies) Caudal: 2 (extending from the posterior end)
Giardia lamblia
32
Worldwide distribution, common in daycare centers and institutionalized populations.
Giardia lamblia
33
Causes blunting of small intestinal villi and malabsorption, often of fats. Symptoms of persistent diarrhea, gas, greasy stools, can become chronic or carriers.
Giardia lamblia
34
Irregular patterns of cysts and trophs in stool samples, but are diagnostic. Molecular methods are available (PCR, antigen)
Giardia lamblia
35
Pathogenicity In females: Vaginitis, pruritus, strawberry cervix In males: Urethritis, prostatovesiculitis Habitat: Genitourinary tract Mode of infection: Sexual contact
Trichomonas vaginalis
36
Lab ID: Specimen source: Vaginal and urethral discharges, prostatic exudates Trophozoite Size 8 to 30μm Flagella: 4 anterior Undulating membrane: 1/3 to 1/2 the length of the organism
Trichomonas vaginalis
37
Pathogenicity: Considered nonpathogenic but often recovered from diarrheic stools Habitat: Colon Mode of infection: Ingestion, direct contact/sexual contact (prominent in homosexual communities)
Pentatrichomonas hominis
38
``` Laboratory identification Specimen source: Feces Trophozoite Size: 8 to 20μm Flagella: 5 anterior and 1 posterior Undulating membrane: Full length ```
Pentatrichomonas hominis
39
Pathogenicity: Considered to be nonpathogenic in the mouth (reported thoracic abscesses and respiratory infections) Habitat: Mouth Mode of infection: Direct contact
Trichomonas tenax
40
Worldwide distribution, humans only Acquired through sexual intercourse or passed to infants during birth
Trichomonas
41
T. vaginalis is pathogenic, the other two are easily confused commensals. T. vaginalis causes itching, petechial hemorrhaging, discharge (strawberry cervix)
Trichomonas
42
Often asymptomatic in men Increased risk of HIV passing or infection Diagnosis: No cyst, 4 anterior flagella with half body undulating membrane
Trichomonas
43
Causes balantidiasis, balantidial dysentery | Diarrhea and secondary complications
Balantidium coli
44
Note: Only pathogenic ciliate.
Balantidium coli
45
``` Life cycle: Habitat: Cecum Reservoir hosts: Swine, hogs Infective form: Cyst stage Mode of infection: Ingestion ```
Balantidium coli
46
Nucleus: Two Macronucleus: Large, elongated (kidney-bean shape) Micronucleus: Minute, spherical
Balantidium coli
47
Trophozoite form Cytoplasm Cytopyge: Excretory opening at posterior end of cell Contractile vacuoles: One or two; pulsating (osmoregulatory function)
Balantidium coli
48
Cytoplasm Transparent cyst wall Remnants cilia and gullet
Balantidium coli
49
Worldwide distribution, but endemic in Japan, South Africa, C & S America, New Guinea Acquired by eating contaminated food and water with feces from humans or animals.
Balantidium coli
50
Causes ulcer in large intestine similar to E. histolytica, but very rarely travels to other organs. Diagnosis: ID ciliated trophozoite or cyst in stool sample.
Balantidium coli
51
Pathogenicity Causes Primary Amebic Meningoencephalitis (PAM) Central nervous system involvement Rapid progression with high mortality
Naegleria fowleri
52
Lab ID: Specimen source: Cerebral spinal fluid NOTE: Finding the trophozoite in the spinal fluid is sufficient reason to initiate treatment
Naegleria fowleri
53
Wide distribution, thermotolerant, found in hot springs, water above 37 degrees Celsius. Free living amoeba, but can infect humans through the nasal cavity. Causes primary amoebic encephalitis (PAM).
Naegleria fowleri
54
Death can occur within 5 days, rapid diagnosis and treatment essential. Diagnosis: Amoeba isolated from CSF
Naegleria fowleri
55
Pathogenesis: Terramebiasis
Acanthamoeba species
56
Meningoencephalitis: Subacute; chronic (prominent species are A. castellani and A. culbertsoni)
Acanthamoeba species
57
Keratitis: Severe damage to eyes; blindness (prominent species are A. castellani and A. polyphaga),early on tied heavily to homemade contact lens solutions
Acanthamoeba species
58
Habitat: Usually free living; skin, central nervous system and corneal regions of the eye Reservoir hosts: A variety of mammals and invertebrates (oysters, grasshoppers and snails) Infective form: Amebic trophozoites or cysts Mode of infection: Uncertain
Acanthamoeba species
59
Lab ID: Specimen source: Exudates, tissue sections, CSF
Acanthamoeba species
60
Identification of ______ species: Requires differentiation from N. fowleri _______: No flagellated stage Presence of trophozoites and cysts in tissue indicative of ______ species
Acanthamoeba species
61
More ubiquitous environmentally, cysts survive desiccation well. Immune compromised individuals more at risk.
Acanthamoeba spp.
62
Known to cause keratitis after entering eye through non-sterile contact lens solution.
Acanthamoeba spp.
63
Causes a slow granulomatous amoebic encephalitis (GAE). Can enter through breaks in skin and respiratory tract. Diagnosis: Amoeba isolated from eye or brain tissue.
Acanthamoeba spp.
64
Leishmania has 3 types of disease:
a) visceral leishmaniasis b) cutaneous leishmaniasis c) mucocutaneous leishmaniasis
65
Discovered by Ronald Ross in 1903 (Leishman and Donovan)
Leishmani
66
Common names: Kala-azar, Dum-Dum fever
Leishmania donovani complex
67
Darkening of the skin (Kala-azar, black poison) Destruction of reticuloendothelial cells and histiocytes throughout the body Hepatosplenomegaly Frequently fatal (95% for untreated cases) Immunity: Gamma globulins; only after recovery from initial infection
Visceral leishmaniasis Leishmania donovani complex
68
Common name: Oriental sore
Leishmania tropica
69
Initial lesion: Shallow, dry scaly ulcerated lesion Ulceration: Crater-like with thickened edges Secondary bacterial infections common Ulcers leave disfiguration Seldom fatal Immunity: Self-healing process confers immunity
Cutaneous leishmaniasis Leishmania tropica
70
Common name: “Baghdad boil”
Leishmania major
71
Initial lesion: Shallow, dry scaly ulcerated lesion Ulceration: Crater-like with thickened edges Secondary bacterial infections common Ulcers leave disfiguration Seldom fatal Immunity: Self-healing process confers immunity
Cutaneous leishmaniasis (like tropica) Leishmania major
72
Common names: Espundia, uta, chiclero ulcer
Leishmania braziliensis/L. panamensis
73
Ulcers with moist centers Secondary lesions: Destruction of the nasal septum; masses of necrotic tissue Marked deformities Frequently fatal
Mucocutaneous leishmaniasis Leishmania braziliensis/L. panamensis
74
Habitat: Phagocytic macrophages of the reticuloendothelial system Intermediate host: Sandflies of the genus Phlebotomus Reservoir hosts: Cats, dogs, other mammals Infective stage: Promastigote Mode of infection: Injection by the bite of the vector
Leishmania
75
``` Specimen source Tissue impression smears and sections (stained by Wright-Giemsa) Exudates or scraping of lesions Buffy coat preparations of venous blood Bone marrow aspirations Culture on Novy, MacNeal and Nicolle (NNN) medium Animal inoculation: Hamsters Serological testing ``` b) Looking for amastigotes!!!
Leishmania
76
Nearly worldwide distribution Causes 3 different diseases based on species Visceral, cutaneous, mucocutaneous
Leishmania spp
77
Acquired through the bite of an infected sandfly. Promastigotes injected into the skin which become amastigotes once phagocytized.
Leishmania spp
78
Symptoms: vary with species, but fever (twice daily), splenomegaly, skin nodules progressing to ulcers. Diagnosis: Tissue samples from edge of ulcer, PCR and stain for amastigotes in blood or tissue
Leishmania spp
79
Discovery: Sleeping Sickness known in Europe since the 1700s. Discovered in 1895 by Bruce in African cattle: First recovered from humans in 1902.
Trypanosoma
80
Trypanosomes were first observed in the blood of amphibians (frogs, etc.), but since then many other species have been discovered in the blood of many vertebrates, including fish, reptiles, birds and mammals. Much research and investigation has been conducted on this genus because of the great debilitation of infections in humans and domestic animals.
Trypanosoma
81
Common name: African sleeping sickness
Trypanosoma brucei
82
West African sleeping sickness | Affects humans more (reservoir host), spread by riverine TseTse fly
T. brucei gambiense
83
East African sleeping sickness | Affects game animals more (reservoir host), savanna-woodland TseTse fly
T. brucei rhodesiense:
84
Pathogenesis: Often fatal in untreated cases Localized inflammatory reaction near entry site Invasion of lymph nodes: Winterbottom’s sign (posterior cervical lymph nodes involved)
Trypanosoma brucei
85
Invasion of central nervous system (CNS) Disinclination to exertion and lack of interest Reflexes retarded: Difficulty in articulation, incoherent speech, loss of coordination Lapses of diurnal sleep Coma: Usually terminal Evades immune system by varying surface antigens (1000 VSGs)
Trypanosoma brucei
86
Duration: | CHRONIC may last for several years
T. brucei gambiense
87
Easily cured during circulatory invasion; fatal in 12 to 18 months, ACUTE
T. brucei rhodesiense
88
Habitat: Circulatory system, central nervous system, lymph nodes, spleen and other organs _____?: Domestic animals _____?: Game animals
T. brucei gambiense: Domestic animals T. brucei rhodesiense: Game animals
89
Infective stage: Metacyclic trypomastigote Mode of infection: Bite of tsetse flies
Trypanosoma brucei
90
Specimen source: Blood or CSF, thick and thin blood smears | _____ from a lymph node, _____ in blood
gambiense from a lymph node, rhodesiense in blood
91
Common name: Chagas disease
Trypanosoma cruzi
92
Pathogenesis: South American trypanosomiasis
Trypanosoma cruzi
93
Localized severe inflammation: Chagoma; periorbital swelling, ROMANA's SIGN Invasion of host cells: Cardiomyopathy Multiple cardiac symptoms Congestive heart failure Mega-disease: Enlargement of visceral organs; dilatation of digestive tract Frequently fatal
Trypanosoma cruzi
94
Habitat: Circulatory and reticuloendothelial systems; heart muscle; bone marrow, etc. Intermediate hosts (vectors): *Reduviid bugs* (KISSING BUGS) Reservoir hosts: Various mammals; wood rats, opossums, armadillos
Trypanosoma cruzi
95
Infective stage: Metacyclic trypomastigote | Mode of infection: Contamination of infected bug feces in the bite wound; also transfusion and organ transplants
Trypanosoma cruzi
96
Which of these organisms tend to infect liver tissue? A. Giardia lamblia B Leishmania major C. Entamoeba histolytica D. Paragonimus westermani
C. Entamoeba histolytica
97
What would be the best treatment option for giardiasis? A. Metronidazole B. Artemisinin C. Aspirin D. Fluoroquinolone
A. Metronidazole
98
``` Which of these diseases has been termed the “Baghdad boil”?   A. Trypanosomiasis B. Cryptosporidiosis C. Acanthamoeba infection D. Leishmaniasis ```
Leishmania major
99
periorbital swelling (T. Cruzi)
ROMANA's SIGN
100
Mega-disease: Enlargement of visceral organs; dilatation of digestive tract
T. Cruzi

MicroBio - Parasitology (14 decks)

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