Parasites Flashcards

1
Q

Infective form of naegleria fowleri

A

Free living amoebic trophozoites

Transmission by inhalation

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2
Q

naegleria fowleri affects

A

Olfactory nerve, penetrates cribriform palate

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3
Q

Tissue destruction by naegleria fowleri mediated by

A

Ingestion of brain tissue by amoebostome

Contact dependent cytolysis

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4
Q

naegleria fowleri causes

A

Primary amoebic meningoencephalitis

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5
Q

Incubation period of naegleria fowleri

A

1-2 weeks

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6
Q

Early symptoms of naegleria fowleri

A
Taste and smell changes
Headache
Nausea, vomiting
High fever
Stiff neck, +Kernig's sign
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7
Q

Late symptoms of naegleria fowleri

A

Confusion
Hallucinations
Ataxia
Seizures

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8
Q

Specimen to be collected for naegleria fowleri

A

CSF

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9
Q

CSF properties in naegleria fowleri

A

Thick, purulent
Pus cells >20,000/microl
Inc. protein, dec. Sugar

Trophozoites detected in microscopy

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10
Q

Histopathology of naegleria fowleri

A

Brain biopsy
H&E/Giemsa
Trophozoites with sky blue cytoplasm and pink nucleus

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11
Q

Culture for naegleria fowleri

A

Non nutrient agar

Trail sign - naegleria feeds on bacteria and crawls over lawn culture of E.Coli

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12
Q

Special test for naegleria fowleri

A

Enflagellation test
When scrapping of non nutrient agar is transferred to sterile tubes, amoeboid form transforms into pear shaped flagellated form

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13
Q

CT/MRI for naegleria fowleri

A

Obliteration of cisterns

Diffuse enhancement

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14
Q

Toxoplasma gondii is (intra/extra)

A

Obligate intracellular

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15
Q

Morphological forms of Toxoplasma gondii

A
Tachyzoites
Pseudocyst
Tissue cyst
Sporulated oocyst
Sporozoites/bradyzoites
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16
Q

C/F of Toxoplasma gondii in immunocompetents

A
Flu like symptoms
Cervical lymphadenopathy
Headache
Fever
Malaise
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17
Q

C/F of Toxoplasma gondii in HIV

A
necrotising encephalitis
Seizures
C.N palsies
Altered mental status
Motor defects
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18
Q

C/F of Toxoplasma gondii in congenital

A

3rd trimester
Intracranial calcifications
Hydrocephaly
Chorioretinitis

Microcephaly

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19
Q

Toxoplasma gondii direct microscopy

A

PBS, body fluids, bone marrow aspirate, l.n aspirate
Giemsa, PAS
Comma shaped tachyzoites
Tissue cyst in muscle and brain tissue

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20
Q

Ab detection in Toxoplasma gondii

A

IgG - 4 fold rise needed. Can’t differentiate
IgM - confirms congenital
IgA - acute and congenital

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21
Q

Special test for Toxoplasma gondii

A

Sabin Feldman Dye Test
Detects IgG
Complement mediated neutralization test
Needs live tachyzoites

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22
Q

CT/MRI for Toxoplasma gondii

A

Multiple ring enhancing lesions

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23
Q

CSF of Toxoplasma gondii

A

Inc. ICP
Lymphocytosis
Normal glucose

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24
Q

Antenatal DX of Toxoplasma gondii

A

Ultrasonography

PCR/isolation using amniotic fluid

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25
Q

Postnatal DX of Toxoplasma gondii

A

Isolation from amniotic fluid, placenta, cord leukocyte
IgG > 1000 in neonates
IgM > 1:4 in neonates

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26
Q

African sleeping sickness caused by

A

Trypanosoma brucei gambiense

Trypanosoma brucei rhodesiense

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27
Q

Vector for African sleeping sickness

A

Tsetse fly

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28
Q

Forms of Trypanosoma

A

Infective - metacyclic promastigote
Long slender trypomastigote
Epimastigote

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29
Q

Special feature of trypanosoma

A

Variable Surface Glycoprotein (VSG) Ag

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30
Q

Stage 1 of African sleeping sickness

A

1 wk - trypanosomal chancre (self limiting)
Few months - asymptomatic
Systemic febrile illness

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31
Q

What is systemic febrile illness in African sleeping sickness

A

Due to dissemination of parasite through lymph and blood
Remittant irregular fever and night sweats
Posterior cervical lymphadenopathy- winterbottom sign

32
Q

What is winterbottom sign

A

Posterior cervical lymphadenopathy in systemic febrile illness in African sleeping sickness

33
Q

Stage 2 of African sleeping sickness

A

CNS invasion
Day time somnolence
Night time restlessness and insomnia

34
Q

What causes C/F of CNS invasion in African sleeping sickness

A

Inc. PGD2

35
Q

Blood microscopy in Trypanosoma

A

Trypomastigote forms

36
Q

CSF microscopy in Trypanosoma

A

Trypomastigotes in CSF
or
WBC > 20 cells / micro l
Parasites in blood

37
Q

Ag and Ab detection in Trypanosoma

A

Ag - ELISA
Ab -
Card agglutination test
Semi quantitative ELISA

38
Q

Special test for Trypanosoma

A

FISH - Florescent In Situ Hybridization

Molecular method

39
Q

Culture for Trypanosoma

A

KIVI kit

40
Q

Opportunistic coccidians

A

Cryptosporidium
Cyclospora
Cystoisospora

41
Q

Life cycle stages of cryptosporidium

A
Parasitophorous vacuole
Schizont
Merozoites
Gametes
Oocyst
42
Q

cryptosporidium stages in pathogenesis

A
Excystation
Attachment
Penetration
Vacuole
Cytokines
43
Q

Excystation cryptosporidium

A

Oocyst secretes proteases and aminopeptidases

44
Q

Attachment cryptosporidium

A

Attach to brush border using CP47 virulence factor

45
Q

Penetration cryptosporidium

A

By apicomplex discharge

46
Q

Vacuole cryptosporidium

A

Parasitophorous vacuole formed

47
Q

Cytokines cryptosporidium

A

TNF, IL8, PG cause inflammation

48
Q

C/F of cryptosporidium in immunocompetent host

A

Self limiting watery diarrhea

49
Q

C/F of cryptosporidium in immunocompromised host

A

Chronic persistent watery diarrhea

50
Q

Stool wet mount of cryptosporidium

A

Refractile, double walled cysts

Concentration technique - sheathers sugar floatation technique

51
Q

Microscopy of stool cryptosporidium

A

Acid fast stain - red oocysts on blue background
Direct Florescent Ab
Auto fluorescence test

52
Q

Histology of cryptosporidium

A

H&E - blue bead appearance

53
Q

Schistosomes are also called

A

Blood flukes

54
Q

Stages in life cycle of schistosomes

A

Cercaria larva
Adult worm
Miracidium
Sporocyst

55
Q

3 stages of S. Mansoni

A
Cercarial dermatitis (swimmers itch)
Acute schistosomiasis (katayama fever)
Chronic schistosomiasis
56
Q

Acute schistosomiasis S. Mansoni

A

Ags from eggs stimulate immune complex formation and serum sickness - katayama fever

Fever
Generalized lymphadenopathy
HSM

57
Q

Chronic schistosomiasis S. Mansoni

A

Diarrhea
Portal HTN
Cirrhosis
Nephrosclerosis

58
Q

Eggs of S. Mansoni detected by

A

Hatching test - hatching of motile miracidia from eggs when stool specimen is diluted and beam is light is passed through it

59
Q

Histology of S. Mansoni

A

Egg shell - acid fast (ZN)

Lateral spine

60
Q

Other tests for S. Mansoni

A

Dipstick test

ELISA

61
Q

C/F of S. Japonicum

A

Swimmers itch
Katayama fever
Portal HTN, cirrhosis (esp. left lobe)
Cerebral schistosomiasis

62
Q

Eggs of S. Japonicum

A

Seen in stool

Small spine

63
Q

Special tests for S. Japonicum

A

Pyrosequencing assay - detect DNA

Magnetic fractionation method - egg-microsphere conjugate formed

64
Q

Acute infection of S. Hematobium

A

Swimmers itch

Pruritic papular lesion

65
Q

Chronic infection of S. Hematobium

A
Spines damage bladder mucosa
Hematuria
Egg granuloma (type 4 HSR)
Elephantiasis in scrotum and penis
Hydroureter, hydronephros
Bladder carcinoma (SCC or transitional cell carcinoma)
66
Q

Microscopy of S. Hematobium

A

Urine sample - terminal hematuria portion

Terminal spined eggs

67
Q

Histology of S. Hematobium

A

Bladder mucosa biopsy or wet cervical biopsy

68
Q

Ab detection in S. Hematobium

A

HAMA-FAST-ELISA

HAMA-EITB

69
Q

Ag detection in S. Hematobium

A

Circulation cathodic and anodic Ag (CCA, CAA)
detected by ELISA

CCA>CAA

70
Q

Diphyllobothrium latum also called

A

Fish tapeworm

71
Q

Life cycle stages of Diphyllobothrium

A

Plerocercoid larvae (L3)
Coracidium (,L1)
Procercoid (L2)

72
Q

C/F of Diphyllobothrium

A

Diarrhea
Vit B12 deficiency
Megaloblastic anaemia

73
Q

Lab dx of Diphyllobothrium

A

Stool - eggs, segments of adult worm
Molecular - PCR
Blood - eosinophilia, Marcocytes

74
Q

Life cycle stages of hymenolepis Nana

A

Cysticercoid larva
Adult worm
Eggs
Ingested by rat flea

75
Q

C/F of hymenolepis

A

Diarrhea with mucus

76
Q

Egg of hymenolepis

A
Non bile stained
Hooklets
Polar thickening
Polar filament
Yolk granules