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PARASITOLOGY > MIDTERM: COCCIDIANS > Flashcards

MIDTERM: COCCIDIANS Flashcards

1
Q

 Phylum Apicomplexa (The coccidian parasites are
the LARGEST GROUP of apicomplexan protozoa falling under Class Conoidasida.)
 Spore forming, microscopic, single-celled parasites
(withstand extreme conditions of starvation, acidity,
temperature, and desiccation by producing resistant
forms called “spores.”)
 OBLIGATE INTRACELLULAR (which means they strictly need host cell in order to reproduce)
 Intracellular parasites are microparasites that are
capable of growing and reproducing inside the
cells of a host.
 Order Eucoccidiorida Suborder
Eimeriorina

A

COCCIDIANS

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2
Q

MEMBERS

A
  1. Cystoisospora
  2. Cyclospora
  3. Cryptosporidium
  4. Toxoplasma
  5. Sarcocystis
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3
Q

ALL MEMBERS OF COCCIDIANS ARE HOST SPECIFIC EXCEPT for?

A

Toxoplasma gondii

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4
Q

3 sequential stages:

A

SPOROGONY
SCHIZOGONY/MEROGONY
GAMETOGONY

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5
Q

produces oocysts containing trophozoite

A

Sexual or Sporogony

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6
Q

production of merozoites (meronts)

A

Asexual or Schizogony or Merogony

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7
Q

Development of micro (male), macro (female)
gametocytes (gamonts)

A

Gametogony

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8
Q

a dormant stage of protozoa which facilitates the
survival during unfavourable environmental conditions

A

CYST

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9
Q

reproductive cell): Present in the life cycle of protozoa which contains a zygote within it. A reproductive structure that is formed by a protozoa to aid in transmission to a new host.

A

OOCYST

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10
Q

a nucleated and long asexual stage of coccidians.

A

MEROZOITES (MERONTS)

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11
Q

motile, spore-like stage in the life cycle of
a protozoan

A

SPOROZOITES

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12
Q

activated, feeding stage in the life cycle of
protozoan parasite

A

TROPHOZOITES

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13
Q

a cell that divides by schizogony to form daughter
cells; multinucleate sporozoan that reproduces by schizogony.

A

SCHIZONT

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14
Q

 all stages of development completed in
gastrointestinal tract
 found mainly in humans
 causes CRYPTOSPORIDOSIS
 oocysts found in the human and animal feces
 attach to epithelial cells:
- outside cytoplasm (within brush
borders)
- located intracellular but
extracytoplasmic
 Mode of transmission: WATERBORNE (common)

A

Cryptosporidium hominis

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15
Q

Only specie that infect mammals is the __________
MOT: zoonotic and anthroponotic

A

Cryptosporidium parvum

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16
Q

 roundish (4 to 6 Um)
 contains 4 sporozoites present in feces
o Turns to small trophozoite then divided
by schizogony producing merozoites
(micro and macrogamete)

A

Cryptosporidium hominis OOCYST

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17
Q

Cryptosporidium hominis OOCYST Merozoite type 1 contains how many nuclei?

A

8

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18
Q

Cryptosporidium hominis OOCYST Merozoite type 2 contains how many nuclei?

A

4

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19
Q

o Burst inside the small intestine and releases
sporozoite
o INTERNAL AUTOINFECTION

A

Cryptosporidium hominis OOCYST THIN - WALLED

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20
Q

o 1-6 dark granules may be viable
o Passed in the feces
o EXTERNAL AUTOINFECTION

A

Cryptosporidium hominis OOCYST THICK - WALLED

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21
Q

INFECTIVE STAGE OF Cryptosporidium hominis

A

OOCYST

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22
Q

CLINICAL MANIFESTATION
 SELF - LIMITED DIARRHEA lasting for 2 to 3
weeks
 Other manifestation: abdominal pain, anorexia, fever, nausea, and weight loss

A

CRYPTOSPORIDIOSIS on Immunocompetent Host

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23
Q

CLINICAL MANIFESTATION
 MORE SEVERE DIARRHEA, progressive and may become life threatening
 Acute and Gangrenous cholecystitis
 Dyspnea, chronic cough, bronchiolitis, pneumonia
 Blunted intestinal Villi: malabsorption and excessive fluid loss

A

CRYPTOSPORIDIOSIS on Immunocompromised Host

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24
Q

Commonly used technique to detect oocyst in Cryptosporidium hominis

A. Acid-fast staining
B. Sheather’s sugar flotation
C. Kinyoun’s modified acid fast stain
D. Formalin ether/acetyl concentration test (FECT)

A

B & D
- Sheather’s sugar flotation
- Formalin ether/acetyl concentration test (FECT)

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25
Q

Cryptosporidium hominis DIAGNOSIS
- Routinely used with the oocysts (appear as RED PINK)
- appearing red-pink doughnut-shaped circular
organisms in blue background

A. Acid-fast staining
B. Sheather’s sugar flotation
C. Kinyoun’s modified acid fast stain
D. Formalin ether/acetyl concentration test (FECT)

A

C. Kinyoun’s modified acid fast stain

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26
Q

Cryptosporidium hominis DIAGNOSIS
- probably the quickest and cheapest method of diagnosis

A. Acid-fast staining
B. Sheather’s sugar flotation
C. Kinyoun’s modified acid fast stain
D. Formalin ether/acetyl concentration test (FECT)

A

A Acid-fast staining

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27
Q

Cryptosporidium hominis treatment that is reported effective in preliminary/clinical trials

A

Nitazoxanide

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28
Q

Used to treat severe diarrhea

A

o Bovine colostrum
o Paromomycin
o Clarithromycin
* Azithromycin

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29
Q

 Causes CYCLOSPORIASIS
 originally called a CYANOBACTERIUM-LIKE body (CLB)
 Showed organelle that undergoes photosynthesis
and autofluorescence.
 Acid-fast variable resembling “wrinkled
cellophane-unstained”
 invades the epithelial cells of the small intestines
o site of predilection: jejunum
 MODE OF TRANSMISSION: Ingestion of sporulated
oocyst

A

Cyclospora cayetanensis

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30
Q

 7 – 10 um in diameter
 Ingestion, contains two sporocysts with two
sporozoites each then invades the small intestine
 Multiple fissions of these sporozoites take place
inside the cells to produce meronts

A

Cyclospora cayetanensis OOCYTS

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31
Q

Cyclospora cayetanensis OOCYST First generation contains how many merozoites?

A

8 - 12

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32
Q

Cyclospora cayetanensis OOCYST second generation contains how many merozoites?

A

only 4

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33
Q

infective stage of Cyclospora cayetanensis

A

Cyclospora cayetanensis SPORULATED OOCYST/OOCYTE

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34
Q

Cyclospora cayetanensis OOCYST undergo complete sporulation within ____ days in a _____ environment.

A

7 to 12 , warm

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35
Q

malaise, low grade fever (12-24 hours
post exposure)

A

Initial Symptoms

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36
Q

proximal small intestine malabsorption

A

D-xylose malabsorption

37
Q

Cyclospora cayetanensis DIAGNOSIS:

Recommended diagnostic test?

A

Direct microscopic examination (HPO) of DFS

38
Q

Cyclospora cayetanensis DIAGNOSIS:
- Differentiates Cyclospora from Eimeria spp.

A

Polymerase chain reaction

39
Q

Cyclospora cayetanensis other diagnostic test:

A

 Acid fast staining (Kinyoun’s stain)
 Oocyst: auto fluorescent
o Fluorescent microscopy: blue or
green circles
 Safranin staining and microwave heating

40
Q

treatment for CYCLOSPORIASIS

A

Trimethoprim-sulfamethoxazole
o 160/800 mg twice daily for 7 days

41
Q
  • causes Cystoisosporiasis
  • Humans are the only host
  • sporulated oocysts contains 2 sporocysts each
    containing 4 sporozoites
  • Sporulation usually occurs within 48 hours after
    passage with the stool.
  • Habitat: small intestine
  • MODE OF TRANSMISSION: Ingestion of a MATURE
    OOCYST
A

Cystoisospora belli

42
Q
  • 25 -35um long, 10 – 15 um wide; TRANSPARENT; oval;
  • cell wall is 2 layered, colorless and smooth
  • developing sporoblast is unicellular with granular cytoplasm
A

Cystoisospora belli OOCYST

43
Q

o is elongated and ovoidal (20-33u x 10-19u)
o Has 2 sporoblast

A

Cystoisospora belli IMMATURE OOCYST

44
Q

 2 sporocysts with 4 long and slender (sausage shaped) sporozoites each
 Total of 8 sporozoites

A

Cystoisospora belli MATURE SPORULATED OOCYST

45
Q

Cystoisosporiasis is more common on ____and ____________________

A

children,immunocompromised patients

46
Q

o Generally ASYMPTOMATIC or self-limiting gastroenteritis
o Stools contain undigested food, mucus, and Charcot-Leyden crystals

IMMUNOCOMPETENT OR IMMUNOCOMPROMISED?

A

IMMUNOCOMPETENT

47
Q

o Self-limiting enteritis to severe diarrheal illness
o Mucosal bowel biopsy may reveal flattened mucosa and damaged villi

IMMUNOCOMPETENT OR IMMUNOCOMPROMISED?

A

IMMUNOCOMPROMISED

48
Q

Prolonged Mild diarrhea, Abdominal pain may
lead to _________ with weight loss

A

Malabsorption syndrome

49
Q

Oocysts of C. belli may be detected in feces
through:

A

Direct microscopy/FECT

50
Q

Other concentration:

A

Zinc sulphate, Sugar floatation, Enterotest

51
Q

oocysts can be seen in a fecal smear stained
by a _________________ (granular red color against a green background)

A

Modified Ziehl-Neelsen method

52
Q

Help visualize the organism:

A

o Phenol-auramine
o iodine staining

53
Q

FOR BLOOD EXAMINATION?

A

peripheral eosinophilia

54
Q

Asymptomatic infections:

A

bed rest and bland diet

55
Q

Symptomatic infections:
 For AIDS patient

A
  • Trimethoprim- sulfamethoxazole 160/800 mg (4/day for 10 day) then (2/day for 3 weeks)
  • Combination therapy with pyrimethamine and
    sulfadiazine for 7 weeks
56
Q
  • coccidian that belongs to the Phylum Apicomplexa - has worldwide distribution
  • causes TOXOPLASMOSIS, CONGENITAL
    TOXOPLASMOSIS, CEREBRAL
    TOXOPLASMOSIS
  • Infects humans and many species of animals.  Hosts:
  • Definitive host: Cat family (Felidae)
  • Intermediate host: other animal like
    mouse, bird, rodents, pigs, cows, sheep
  • Accidental host: Humans
A

Toxoplasma gondii

57
Q

infective stages of Toxoplasma gondii

A
  • Sporulated oocyst
  • Encysted bradyzoites
  • Motile tachyzoites
58
Q

Toxoplasma gondii unsporulated oocyst undergo sporulation for how many days?

A

3 - 4 days

59
Q

Toxoplasma gondii mot for accidental host (human)

A
  • Consuming contaminated food or water
  • eating raw/undercooked meat
  • blood transfusion
  • trans placental infection
  • transplantation
60
Q

Diagnostic specimens and stages of Toxoplasma gondii

A
  • Tissue biopsy showing encysted bradyzoites
  • Blood smear showing tachyzoites
  • Serum or CSF for serologic testing
61
Q

FORMS OF Toxoplasma gondii
- Found in the stool of definitive host
- ovoidal, thin wall
- 10 - 13 um by 9 to 11 um
- Contain 2 sporocysts, each sporocysts
contains 4 sporozoites

A

Toxoplasma gondii OOCYST

62
Q

FORMS OF Toxoplasma gondii
- ACTIVELY multiplying morphologic form
- 3-7 um x 2-4 um
- Crescent – shaped, often more rounded on one end
- Single central nucleus
- Contains a variety of organelles that are not readily visible
- found during the initial and acute stage of the infection

A

Toxoplasma gondii TACHYZOITE

63
Q

FORMS OF Toxoplasma gondii
- SLOW-GROWING morphologic form
- Smaller than tachyzoites, appearance is similar to that of the tachyzoites
- single nucleus is located posteriorly
- Hundreds or thousands of bradyzoites enclosed themselves to form a cyst that may measure 12-100 um in diameter

A

Toxoplasma gondii BRADYZOITE

64
Q

CLINICAL MANIFESTATION of Toxoplasma gondii
o commonly asymptomatic as long as the immune system of the patient is functioning well.
o recognized as an important disease associated with AIDS.

A

TOXOPLASMOSIS

65
Q

CLINICAL MANIFESTATION of Toxoplasma gondii
- most common manifestation among the immunocompromised patients

A

Encephalitis:

66
Q

DIAGNOSTIC TEST used to detect antibodies against T. gondii (positive titer or a four-fold increase in titers)

A

Serodiagnostic methods:

67
Q

very sensitive and specific but it requires the maintenance of live organisms in the laboratory

A

Sabin-Feldman methylene blue dye test

68
Q

o successfully used in the diagnosis of toxoplasmosis
o Samples taken: serum, amniotic fluid, cerebrospinal fluid, and bronchoalveolar lavage

A

Polymerase chain reaction

69
Q

Used in combination for 1 MONTH, keeps Toxoplasma under control but DO NOT KILL
IT:

A

PYRIMETHAMINE (25 – 100 mg daily) and
SULFADIAZINE (1 – 1.5 g 4 times daily)

70
Q

o can lower blood counts
o given together with leucovorin (folic acid)

A

Pyrimethamine

71
Q

o cause serious allergic reactions like fever and rash
o can be substituted with clindamycin

A

Sulfadiazine

72
Q

given to prevent occurrence of hypersensitivity reactions

A

Corticosteroids

73
Q

given for the immunocompromised:

A

Prophylaxis with trimethoprim-sulfamethoxazole

74
Q
  • Causes Sarcosporidiosis or Sarcocystosis
  • Definitive host: Humans  Intermediate host: cattle (S. hominis) and pigs (S. suihominis)
A

Sarcocystis spp.

75
Q
  • Oval, transparent o Contains 2 sporocysts (10-18 um long)
  • Each sporocysts contains 4 sausage-shaped sporozoites
  • Cell wall: Clear, colorless, double-layered
A

Sarcocystis spp. MATURE OOCYST

76
Q

o first reported this parasite in 1843
o described it as a white thread like cyst in striated muscles of a house mouse

A

Miescher

77
Q

Sarcocystis spp. referred to as ________ until 1899

A

Miescher’s tubules

78
Q

Sarcocystis spp. 1st proposed name:

A

Sarcocystis miescheriana

79
Q

Sarcocystis spp. Infective Stage:

A

OOCYST or FREE SPOROCYST (sarcocyst containing bradyzoites)

80
Q

Sarcocystis spp. MOT?

A

consumption of uncooked or undercooked meat of intermediate host that contains sarcocysts

81
Q

Sarcocystis spp. in the PHIL.
- in backyard cattles, has type 7 sarcocyst wall

A

S. cruzi

82
Q

Sarcocystis spp. in the PHIL.
- in water buffaloes, has type 7 sarcocyst wall, with
similarities to S. cruzi

A

S. levinei

83
Q

Sarcocystis spp. in the PHIL.
- in domestic pigs, has type 10 sarcocyst wall

A

S. miescherenia

84
Q

Sarcocystis spp. in the PHIL.
- in domestic goats, has type 14 sarcocyst wall

A

S. capracanis

85
Q
  • Simplest form of Sarcocystis
  • Banana-shaped cell
  • Has a pointed anterior end
  • Hosts: pigs, ducks, birds
A

Sarcocystis spp. ZOITE

86
Q
  • Size: 15-19um by 8-10um
  • Contains 4 sporozoites and a discrete
    refractile residual body
  • Capable of surviving on the ground and
    infecting intermediate hosts
A

Sarcocystis spp. SPOROCYSTS

87
Q

CLINICAL MANIFESTATION OF Sarcocystis spp.
o presents with vasculitis and myositis
o involve a wide variety of tissues (lymph nodes, muscles, and the larynx)

A

Rare Invasive Form

88
Q

CLINICAL MANIFESTATION OF Sarcocystis spp.
o presents with nausea, abdominal pain, and diarrhea
o normally mild and lasting under 48 hours
o occasionally be severe or even life threatening

A

Intestinal form

89
Q

DIAGNOSIS OF Sarcocystis spp.

A
  • Fecal floatation wet mount
  • Biopsy of an infected muscle

PARASITOLOGY (23 decks)

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