Parasitology Review

1. PART I

2. laboratory methods
protozoa
blood and tissue
intestinal and urogenital

3.  examination of blood
 examination of fecal specimens
 examination of urogenital and other
specimens (sputa, aspirates, biopsies)
 immunodiagnostic methods
 molecular diagnostic methods
laboratory methods

4. examination of blood
 malaria, babesiosis, trypanosomiasis,
leishmaniasis, filariasis
 thick and thin blood films
 concentration techniques
QBC blood parasite detection method
Knott’s concentration or membrane filtration

5. examination of blood
species ID
parasite detection
GIEMSA stain
- host cell & parasite chromatin;
Hb in rbc stains pale red
- only stain that allows visualization of the rbc stippling

6. examination of blood
species ID parasite diagnosis
at least 200 fields (requiring at least
15 mins) using 100x objective
at least 100 oil immersion fields
(requiring at least 5 mins)

7. examination of blood
 concentration techniques
QBC blood parasite detection method
uses fluorochrome acridine orange in a
microhematocrit centrifuge format
more sensitive than traditional thick/thin smears

8. examination of blood
 Centrifugation (Knott’s technique)
 Prepare 2% formaldehyde
(2 ml of 37% formaldehyde + 98 ml H2O).
 9 ml 2% formaldehyde + 1 ml of patient’s venous blood
 centrifuge at 500 × g for 10 minutes
 discard supernatant.
 sediment = WBCs and microfilariae (if present).
 temporary wet mounts.
 thick and thin smears
 allow to dry
 dip in absolute methanol before Giemsa staining to enhance
staining of microfilariae

9. examination of blood
 Filtration
 Millipore® or Nucleopore® membrane filter (5 µm
pore) in filter holder with syringe attachment
 1 ml of venous blood (in EDTA) + 10 ml of 10%
Teepol® 610 (Shell Co.); allow to stand for several
minutes to allow lysis;
 transfer to a 10 ml Luer-Loc® syringe
 attach the filter apparatus.
 force the solution through the 5 µm pore filter,
followed by several syringes of water to wash out the
remaining blood, then 1 or 2 syringes full of air to
clear excess fluid.
 temporary wet mount: remove the filter and place it
on a glass slide, adding a drop of stain or dye and a
coverslip
 permanent slide: pass 2 to 3 ml of methanol through
the filter while it is still in the holder; remove filter and
dry it on a glass slide; then stain it with Giemsa stain,
horizontally (so that the filter does not wash off the
slide); coverslip filter before examining.

10. examination of fecal specimens
 specimen collection, handling & preservation
 macroscopic examination
 microscopic examinations
direct wet mount
concentration techniques
permanent stains
wheatley’s trichrome stain
iron hematoxylin stain
modified acid-fast stains
stains for microsporidia
additional techniques for examination of enteric parasites
cellulose tape technique for pinworms
egg studies
nematode culture & recovery techniques

11. examination of fecal specimens
 specimen collection, handling & preservation
 fresh specimens: examined w/n 1 hr of passage
 liquid specimens: w/n 30 minutes or placed
immediately in preservatives
 clean containers w/ tight-fitting lids
 preservatives:
2-vial technique: 5-10% buffered formalin
polyvinyl alcohol (PVA) fixative
merthiolate-iodine-formalin (MIF)
sodium acetate-formalin (SAF)
zinc-sulfate-based PVA

12. examination of fecal specimens
 specimen collection, handling &
preservation
 adequate O & P evaluation:
3 specimens collected every other day
purgation
 sodium sulfate, buffered phosphosoda
 specimens collected in separate containers and submitted
w/n minutes of collection
G. lamblia
Strongyloides
E. histolytica

13. examination of fecal specimens
 macroscopic examination
consistency
 formed
 soft
 loose
 watery
+ mucus, blood, larval or adult worms & proglottids
CYSTS
TROPHOZOITES

14. examination of fecal specimens
 microscopic examinations
 direct wet mounts of fresh or preserved material
fresh: allow detection & observation of motile protozoan
trophozoites & helminth larvae
preserved: allow detection of parasites that do not
concentrate well
 concentration techniques
more sensitive
increase the examiner’s ability to detect protozoan cysts &
helminth eggs & larvae
unsatisfactory for detecting protozoan trophozoites
 permanent stains
useful for detection & morphologic examination of protozoan
trophozoites & cysts

15. examination of fecal specimens
 microscopic examination
 direct wet mount
small amt of stool + drop of 0.85% saline
(NaCl), covered w/ coverslip
10x, 40x
or 1:5 dilution of Lugol’s iodine
loss of trophozoite motility & cyst refractility
difficulty in recognizing chromatoid bodies
organisms: very pale and transparent
(refractile objects)
low light intensity

16. examination of fecal specimens
 microscopic examination
 concentration techniques
 zinc sulfate centrifugal flotation technique of
Faust
 fresh/formalinized stool
 parasites are recovered from the surface film of
the solution following centrifugation
 yields a cleaner preparation
 unreliable for the recovery for nematode larvae,
infertile eggs of ascaris, & the eggs of most
trematodes & large tapeworms

17. examination of fecal specimens
 microscopic examination
 concentration techniques
 formalin-ether/ethyl acetate sedimentation of
Ritchie
 efficient in recovering most protozoan cysts & helminths
eggs & larvae, including operculate eggs
 moderately effective for schistosome eggs
 easiest to perform and least subject to technical error
 less distortion of protozoal cysts than flotation
technique

18. examination of fecal specimens
 microscopic examination
 permanent stains [100x]
WHEATLEY’S TRICHROME STAIN
IRON HEMATOXYLIN STAIN
MODIFIED ACID-FAST STAINS
STAINS FOR Microsporidia
 depend on the age of the specimen, proper smear
preparation & fixation, & quality of the reagents

19. examination of fecal specimens
 microscopic examination
 permanent stains [100x]
WHEATLEY’S TRICHROME STAIN
 most common: simple, reliable, cost-effective
 stool specimens + Schaundinn’s or PVA fixatives

20. examination of fecal specimens
 microscopic examination
 permanent stains [100x]
IRON HEMATOXYLIN STAIN
 superior in enhancing key nuclear & cytoplasmic characteristics
 preferred stain for SAF fixative

21. examination of fecal specimens
 microscopic examination
 permanent stains [100x]
MODIFIED ACID-FAST STAINS
 MODIFIED KINYOUN METHOD
 MODIFIED ACID-FAST DIMETHYL SULFOXIDE
 AURAMINE-O
 sensitive & cost-effective
 lack specificity

22. examination of fecal specimens
 microscopic examination
 permanent stains [100x]
STAINS FOR Microsporidia
 *Modified Trichrome Stain
 Fluorescent Staining Method using whitening agents,
Uvitek-2B & Calcofluor white

23. examination of fecal specimens
 additional techniques for examination of
Enteric Parasites
CELLULOSE TAPE TECHNIQUE (PINWORMS)
EGG STUDIES
NEMATODE CULTURE & RECOVERY
TECHNIQUES

24. examination of urogenital & other
specimens [sputa, aspirates, biopsies]
 Direct Wet mount
 10X: Trichomonas vaginalis - jerky
movement
 Acid-fast or specific antibody-based stains
 Cryptosporidium
 Modified trichrome or fluorochrome stains
 Microsporidia
 same methods used in sputa
 Giemsa stain (hemoflagellates)
vaginal & urethral
discharges,
prostatic secretions,
urine
sputa
aspirates

26. Immunodiagnostic methods

27. Molecular Diagnostic methods

28. blood & tissue protozoa
Malaria
Babesiosis
Hemoflaggelates:
Trypanosoma
Leishmania
Toxoplasma gondii
Opportunistic Free-living Amebae

29. Plasmodium species
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium falciparum
female Anopheles
 .
 .

31. Plasmodium spp
morphologic stages:
 GROWING forms
 trophozoites
 DIVIDING forms
 schizonts
 SEXUAL forms
 gametocytes

32. Plasmodium spp
morphologic stages:
 GROWING forms
 trophozoites
 DIVIDING forms
 schizonts
 SEXUAL forms
 gametocytes

33. Plasmodium spp
morphologic stages:
 GROWING forms
 trophozoites
 DIVIDING forms
 schizonts
 SEXUAL forms
 gametocytes

34. Plasmodium spp
 DX
 history of travel
 [+] thick and thin blood films
blood specimens are collected just prior to the next
anticipated fever spike or at the outset of a fever
 shaking chills
 fever (≥400C)
 generalized diaphoresis
 resolution of fever
 synchronous to the rupture of RBCs with the release of
new infectious blood stage forms …..MEROZOITES

35. Plasmodium spp
 DX
 febrile periodicity
tertian : P. vivax/ovale/falciparum
quartan : P. malariae
tropical & temperate areas: P. vivax
tropical areas: P. falciparum
worldwide: P. malariae

36. Plasmodium spp
 THICK blood films
 presence of the parasites
 THIN blood films
 appearance of infected
RBCs
 appearance of parasites
 stages

37.  2-6: Young trophozoites
(ring stage parasites);
 7-18: Trophozoites;
ameboid
 19-27: Schizonts;
 28 and 29:
Macrogametocytes
(female);
 30: Microgametocyte
(male)

38.  1: Normal red cell;
 2-5: Young trophozoites
(Rings);
 6-15: Trophozoites;
 compact
 16-23: Schizonts;
 24:
Macrogametocytes
(female);
 25: Microgametocyte
(male)

39.  1: Normal rbc
 2-5: Young trophozoites (rings);
 6-13: Trophozoites;
 compact
 band form
 14-22: Schizonts;
 23: Developing gametocyte;
 24: Macrogametocyte (female);
 25: Microgametocyte (male)

40.  1: Normal red cell;
 2-18: Trophozoites
 2-10 correspond to
ring-stage
trophozoites;
 19-26: Schizonts
 26: ruptured
schizont;
 27, 28: Mature
macrogametocytes
(female);
 29, 30: Mature
microgametocytes
(male)
size: 1/6 the diameter of RBC
double chromatin dots
applique or accole forms
doubly infected cells

41. blood & tissue protozoa
Malaria
Babesiosis
Hemoflaggelates:
Trypanosoma
Leishmania
Toxoplasma gondii
Opportunistic Free-living Amebae

42. Babesiosis
 Babesia microti : I. scapularis
 Babesia divergens: I. ricinus
 WA1 : I. pacificus
Ixodes sp.
 fever, chills, malaise, anemia
 no febrile periodicity

43. Babesiosis

44. Babesiosis
 fever, chills, malaise,
anemia
 no febrile periodicity
 Hx of residence in or
travel to endemic
areas
 HX of a recent tick
bite
 presence of parasites
in blood films
 IFA
Ixodes sp.
 DX

45. Babesiosis
 multiple rings in 1 RBC
 may form a tetrad
 NO hemozoin pigment in
infected cells
 NO growing trophozoites
& gametocytes

46. blood & tissue protozoa
Malaria
Babesiosis
Hemoflaggelates: KINOPLAST – large mitochondrion
Trypanosoma
Leishmania
Toxoplasma gondii
Opportunistic Free-living Amebae

47. Hemoflagellates
 morphologic forms
 depending on their presence in vertebrate hosts
(human) or their insect vectors

48.  T. brucei rhodesiense
EAST AFRICA
rapidly progressive acute febrile
illness with LAD
CNS involvement is not prominent
 T. brucei gambiense
WESTERN AFRICA
CLASSIC AFRICAN SLEEPING SICKNESS
chronic: intermittent fever, night sweats, malaise
Winterbottom’s sign: cervical LAD
Trypanosoma brucei
Tsetse fly

49. Trypanosoma

50. Trypanosoma brucei
 geographical Hx
 clinical mx
 high total IgG
 BLOOD
 CSF
 pleocytosis
- 50-500 mononuclear
cells per microliter
 presence of parasites
 thick/thin bld films
 buffy coat prep
 LN/BM aspirates
 spun CSF (Giemsa
stain)
 DX

51. Trypanosoma brucei
Thin blood smear stained w/ Giemsa
trypomastigotes
 30 um long
 small kinetoplast
 graceful movement

52. Trypanosoma cruzi
 AMERICAN TRYPANOSOMIASIS
OR CHAGAS DISEASE
Kissing bug/ REDUVIID

53. Trypanosoma cruzei

54. Trypanosoma cruzi
 AMERICAN TRYPANOSOMIASIS
OR CHAGAS DISEASE
 Acute
 mc: <5 y.o.
 malaise, chills, fever,
hepatomegaly,
myocarditis
 Romana’s sign
 Chagoma
 Chronic
 destruction of the effector
cells of the
parasympathetic system by
autoantibodies
 megaesophagus
 megacolon
 alterations of cardiac
conduction system

55. Trypanosoma cruzi
 Acute stage
 thick/thin blood films
 buffy coat prep
 aspirates of chagomas or
enlarged LN
 culture: Novy-MacNeal-
Nicolle medium
 Chronic stage
 MOC: Serodiagnosis
 EIA, IFA, CF
 DX: trypomastigotes

56. Trypanosoma cruzi
Blood Smear. Giemsa stain.
 20 um shorter
 S and C shapes
 larger kinetoplast

57. blood & tissue protozoa
Malaria
Babesiosis
Hemoflaggelates:
Trypanosoma
Leishmania
Toxoplasma gondii
Opportunistic Free-living Amebae

58. Leishmania sp.
 LEISHMANIASIS: disease of RE System
 clinical forms
 CUTANEOUS
old world or oriental sore
new world
 MUCOCUTANEOUS
espundia: L. braziliensis
 VISCERAL
old world: L. donovani
new world: L. chagasi
KALA-AZAR
Sandfly

59. Leishmania

60. Leishmania
 amastigotes
 smears
 imprints
 biopsies
 growth of
promastigotes
in culture
 DX

61. Leishmania…… amastigotes
skin touch imprint
inside the macrophage
BM smear. Giemsa stain.
2-4um
delicate cytoplasm
nucleus
kinetoplast

62. Leishmania….promastigotes
Culture

63. blood & tissue protozoa
Malaria
Babesiosis
Hemoflaggelates:
Trypanosoma
Leishmania
Toxoplasma gondii
Opportunistic Free-living Amebae

64. Toxoplasma gondii
Toxoplasma gondii
• organ transplantation
•blood transfusion
•transplacental

65. Toxoplasma gondii
 Tachyzoites/tissue cyst
 bld/bloody fluids: acute
 tissues : chronic
 H&E stain
 fluorescent or
immunoperoxidase stains
 Giemsa stain
 growth of
promastigotes in
culture
 DX

66. Toxoplasma gondii
tachyzoites
 3x7 um
 crescent-shaped or oval
 central nucleus

67. blood & tissue protozoa
Malaria
Babesiosis
Hemoflaggelates:
Trypanosoma
Leishmania
Toxoplasma gondii
Opportunistic Free-living Amebae
NAEGLERIA
ACANTHAMOEBA
BALAMUTHIA

68.  dx
 autopsy tissue
sections: brain
 antemortem
dx: CSF
• direct wet
mounts
• stained prep
• culture:
• non-nutrient agar
seeded w/ lawn of
heat-killed or living
Escherichia coli

69. NAEGLERIA
 trophozoites
ameboid
10-35 um
large round central
karyosome
CSF. Trichrome stain.
Culture from CSF.

70. NAEGLERIA
Histopathology of amebic meningoencephalitis due to Naegleria fowleri. CDC.
Direct fluorescent antibody stain.

71.  dx
 (autopsy) brain tissue
 culture
• Acanthamoeba
• same w/ Naegleria
• Balamuthia
• tissue culture using
mammalian cell lines

72. Acanthamoeba
CSF.
trophozoites: acanthopodia double-walled cysts

73. Acanthamoeba & Balamuthia
 DX
antigenically distinct
specific monoclonal or polyclonal antisera
in immunofluorescence or
immunoperoxidase assays

74. blood & tissue protozoa

75. intestinal & urogenital protozoa
Amebae
Entamoeba histolytica
Nonpathogenic amebae
Blastocystic hominis
Flagellates
Dientamoeba fragilis
Giardia lamblia
Chilomatrix mesnili
Pentatrichomonas hominis
Trichomonas vaginalis
Other flagellates:
Enteromonas hominis
Retortamonas intestinalis
Trichomonas tenax
Ciliates
Balantidium coli
Coccidia
Isospora belli
Sarcocystis sp.
Cryptosporidium sp.
Cyclospera cayetanensis
Microsporidia

77. Diagnosis:
 MICROSCOPIC
EXAMINATION
 direct wet mount
 permanent stain
 Stool exam
 Aspirates
 LIVER ABSCESS
 last material aspirated
 Tissue sections
 PAS stain
 CULTURE
 E. histolytica/dispar
 EIA ANTIGEN DETECTION
TESTS
 PCR
 DNA probes
 Extraintestinal infections
 Serologic tests
 EIA, ID, IHA

79. trophozoites
cysts

80. NUCLEUS CYTOPLASM
Species Size (Length) Motility Number
Peripheral
Chromatin
Karyosomal
Chromatin
Appearance Inclusions
Entamoeba
histolytica
10-60 mm.
Usual range,
15-20 mm
commensal
form.1 Over 20
mm invasive
form.2
Progressive
with hyaline,
finger-like
pseudopods.
1
Not visible in
unstained
preparations.
Fine
granules.
Usually
evenly
distributed
and uniform
in size.
Small,
discrete.
Usually
centrally
located, but
occasionally
is eccentric.
Finely
qranular.
Red blood
cells
occasionally.
Noninvasive
organisms
may contain
bacteria.
NUCLEUS CYTOPLASM
Species
Size
(Diameter or
length)
Shape Number
Peripheral
Chromatin
Karyosomal
Chromatin
Chromatoid
Bodies
Glycogen
Entamoeba
histolytica
10-20 mm
Usual range,
12-15 mm.
Usually
spherical.
4 in mature
cyst.
Immature
cysts with
1 or 2
occasionally
seen.
Peripheral
chromatin
present.
Fine, uniform
granules,
evenly
distributed.
Small,
discrete,
usually
centrally
located.
Present.
Elongated
bars with
bluntly
rounded
ends.
Usually
diffuse.
Concentrated
mass often
present in
young
cysts. Stains
reddish
brown with
iodine.

82. NUCLEUS CYTOPLASM
Species
Size
(Length)
Motility Number
Peripheral
Chromatin
Karyosomal
Chromatin
Appearance Inclusions
Entamoeba
hartmanni
5-12mm.
Usual range,
8-10 mm.
Usually non-
progressive
but may be
progressive
occasionally.
1
Not visible in
unstained
preparations.
Similar to
E. histolytica.
Small,
discrete,
often
eccentric.
Finely
granular.
Bacteria.
NUCLEUS CYTOPLASM
Species
Size
(Diameter or
length)
Shape Number
Peripheral
Chromatin
Karyosomal
Chromatin
Chromatoid
Bodies
Glycogen
Entamoeba
hartmanni
5-10 mm
Usual range,
6-8 mm.
Usually
spherical.
4 in mature
cyst.
Immature
cysts with
1 or 2 often
seen.
Similar to E.
histolytica.
Similar to E.
histolytica.
Present.
Elongated
bars with
bluntly
rounded
ends.
Similar to E.
histolytica.

84. NUCLEUS CYTOPLASM
Species
Size
(Length)
Motility Number
Peripheral
Chromatin
Karyosomal
Chromatin
Appearance Inclusions
Entamoeba
coli
15-50mm.
Usual range,
20-25 mm.
Sluggish,
non-
progressive,
with blunt
pseudopods.
1
Often visible
in unstained
preparations.
Coarse
granules,
irregular in
size and
distribution.
Large,
discrete,
usually
eccentric.
Coarse, often
vacuolated.
Bacteria,
yeasts, other
materials.
NUCLEUS CYTOPLASM
Species
Size
(Diameter or
length)
Shape Number
Peripheral
Chromatin
Karyosomal
Chromatin
Chromatoid
Bodies
Glycogen
Entamoeba
coli
10-35 mm
Usual range,
15-25 mm.
Usually
spherical.
Occasionally
oval,
triangular, or
other shapes.
8 in mature
cyst.
Occasionally
super-
nucleated
cysts with 16
or more are
seen.
Immature
cysts with 2
or more
occasionally
seen.
Peripheral
chromatin
present.
Coarse
granules
irregular in
size and
distribution,
but often
appear more
uniform than
in
trophozoites.
Large,
discrete,
usually
eccentric but
occasionally
centrally
located.
Present, but
less
frequently
seen than in
E. histolytica.
Usually
splinter-like
with pointed
ends.
Usually
diffuse, but,
occasionally
well defined
mass in
immature
cysts. Stain
reddish brown
with iodine.

86. NUCLEUS CYTOPLASM
Species
Size
(Length)
Motility Number
Peripheral
Chromatin
Karyosomal
Chromatin
Appearance Inclusions
Endolimax
nana
6-12 mm.
Usual range,
8-10 mm.
Sluggish,
usually non-
progressive
with blunt
pseudopods.
1
Visible
occasionally
in unstained
preparations.
None. Large,
irregularly
shaped,
blot-like.
Granular,
vacuolated.
Bacteria.
NUCLEUS CYTOPLASM
Species
Size
(Diameter or
length)
Shape Number
Peripheral
Chromatin
Karyosomal
Chromatin
Chromatoid
Bodies
Glycogen
Endolimax
nana
5-10 mm.
Usual range,
6-8 mm.
Spherical,
ovoidal, or
ellipsoidal.
4 in immature
cysts.
Immature
cysts with
less than 4
rarely seen.
None Large
(blot-like),
usually
central.
Occasionally
granules or
small oval
masses seen,
but bodies as
seen in
Entamoeba
spp. are not
present.
Usually
diffuse.
Concentrated
mass seen
occasionally
in young
cysts. Stains
reddish brown
with iodine.

88. NUCLEUS CYTOPLASM
Species
Size
(Length)
Motility Number
Peripheral
Chromatin
Karyosomal
Chromatin
Appearance Inclusions
Iodamoeba
buetschlii
8-20 mm.
Usual range,
12-15 mm.
Sluggish,
usually non-
progressive.
1
Not usually
visible in
unstained
preparations.
None. Large, usually
central.
Surrounded
by refractile,
achromatic
granules.
These
granules are
often not
distinct even
in stained
slides.
Coarsely
granular,
vacuolated.
Bacteria,
yeasts, or
other
material.
NUCLEUS CYTOPLASM
Species
Size
(Diameter or
length)
Shape Number
Peripheral
Chromatin
Karyosomal
Chromatin
Chromatoid
Bodies
Glycogen
Iodamoeba
buetschlii
5-20 mm.
Usual range,
10-12 mm
Ovoidal,
ellipsoidal,
triangular, or
other shapes.
1 in mature
cyst.
None Large, usually
eccentric.
Refractile,
achromatic
granules on
one side of
karyosome.
Indistinct in
iodine
preparations.
Occasionally
granules
present, but
chromatoid
bodies as
seen in
Entamoeba
spp. are not
present.
Compact,
well-defined
mass. Stains
dark brown
with iodine.

91. intestinal & urogenital protozoa
Amebae
Blastocystic hominis
Flagellates
Dientamoeba fragilis
Giardia lamblia
Chilomatrix mesnili
Pentatrichomonas hominis
Trichomonas vaginalis
Other flagellates:
Enteromonas hominis
Retortamonas intestinalis
Trichomonas tenax
Ciliates
Balantidium coli
Coccidia
Isospora belli
Sarcocystis sp.
Cryptosporidium sp.
Cyclospera cayetanensis
Microsporidia

92. Blastocystic hominis

93. Blastocystic hominis
Size Shape Motility Number of Nuclei Other Features
5-30 mm.
Usual range, 8-10 mm.
Spherical,
oval, or
ellipsoidal
Nonmotile 1, usually, but 2-4 may
be present. Located in
"rim" of cytoplasm.
In binucleated
organisms, the 2 nuclei
may be at opposite
poles.
In quadrinucleated
forms, the 4 nuclei are
evenly spaced around
periphery of cell.
Cell contains large central
body, or "vacuole" with a
thin band, or "rim" of
cytoplasm around the
periphery.
Occasionally a ring of
granules may be seen in
cytoplasm and the cell
appears to have a
"beaded rim."
 may predominate in
heavy infections

94. Blastocystic hominis
trichrome stain

95. intestinal & urogenital protozoa
Amebae
Blastocystic hominis
Flagellates
Dientamoeba fragilis
Giardia lamblia
Chilomatrix mesnili
Pentatrichomonas hominis
Trichomonas vaginalis
Other flagellates:
Enteromonas hominis
Retortamonas intestinalis
Trichomonas tenax
Ciliates
Balantidium coli
Coccidia
Isospora belli
Sarcocystis sp.
Cryptosporidium sp.
Cyclospera cayetanensis
Microsporidia

96. Dientamoeba fragilis
MULTIPLE Stool examinations
 [last portion of the stool evacuated]

97. Dientamoeba fragilis
NUCLEUS CYTOPLASM
Species
Size
(Length)
Motility Number
Peripheral
Chromatin
Karyosomal
Chromatin
Appearance Inclusions
Dientamoeba
fragilis3
5-15
mm. Usual
range, 9-
12 mm.
Pseudopods
are angular,
serrated, or
broad
lobed, and
hyaline,
almost
transparent.
2
(In
approximatel
y 20% of
organisms
only 1
nucleus is
present.)
Nuclei
invisible in
unstained
preparation
s.
None. Large
cluster of
4-8
granules.
Finely,
qranular.
Bacteria:
occasional
ly red
blood
cells.

98. Giardia lamblia

99. Giardia lamblia
 DX
 Microscopic examinations
direct wet mount
concentration techniques (cyst)
permanent stain
 Small bowel aspirates or
String test specimens
 Antigen detection methods

100. Giardia lamblia
Size (Length) Shape Motility
Number of
Nuclei
Number of
Flagella*
Other Features
10-20 mm.
Usual range,
12-15 mm.
Pear
shaped.
“Falling
leaf.”
2
Not visible
in unstained
mounts.
4 lateral.
2 ventral.
2 caudal.
Sucking disk
occupying
1/2-3/4 of
ventral
surface.
Median bodies
lying
horizontally or
obliquely in
lower part of
body.

101. Giardia lamblia
Size (Length) Shape Number of Nuclei Other Features
8-19 mm.
Usual range. 11-12 mm.
Oval or
ellipsoidal.
Usually 4.
Not distinct in
unstained
preparations.
Usually located
at one end.
Fibrils or flagella
longitudinally in
unstained cysts.
Deep staining fibers
or fibrils may be seen
lying laterally or
obliquely across
fibrils in lower part of
cyst.
Cytoplasm often
retracts from a
portion of cell wall.

102. Chilomastix mesnili
Chilomastix mesnili

103. Chilomastix mesnili
Size (Length) Shape Motility
Number of
Nuclei
Number of
Flagella*
Other
Features
6-24 mm.
Usual range,
10-15 mm.
Pear
shaped.
Stiff,
rotary.
1
Not visible
in
unstained
mounts.
3 anterior.
1 in
cytosome.
Prominent
cytostome
extending
1/3-1/2
length of
body.
Spiral
groove
across
ventral
surface.

104. Chilomastix mesnili
Species Size (Length) Shape Number of Nuclei Other Features
6-10 mm.
Usual range, 8-9 mm.
Lemon shaped
with anterior
hyaline knob.
1. Not visible in
unstained
preparations.
Cytostome with
supporting
fibrils. Usually
visible in stained
preparations.

105. Trichomonas vaginalis
asymptomatic

106. Trichomonas vaginalis
 DX:
 vaginal fluid, prostatic fluid, sediments
of freshly passed urine
Direct wet mount
Culture
Immunofluorescent & EIA techniques
monoclonal antibodies
 Papanicolaou-stained gyne smears

107. Trichomonas vaginalis

108. Pentatrichomonas/Trichomonas
hominis
Size (Length) Shape Motility
Number of
Nuclei
Number of
Flagella*
Other Features
8-20 mm.
Usual range. 11-
12 mm.
Pear
shaped.
Nervous,
jerky.
1
Not visible
in
unstained
mounts.
3-5
anterior.
1 posterior.
Undulating
membrane
extending
length of
body.

109. Trichomonas tenax
 nonpathogenic
 occasionally recovered from the oral
cavity

110. Enteromonas hominis
Retortamonas intestinalis

111. Enteromonas hominis
Species Size (Length) Shape Motility
Number of
Nuclei
Number of
Flagella*
Other
Features
Enteromonas
hominis
4-10 mm.
Usual range,
8-9 mm.
Oval. Jerky. 1
Not visible
in
unstained
mounts.
3 anterior.
1 posterior.
One side of
body
flattened.
Posterior
flagellum
extends
free
posteriorly
or laterally.

112. Enteromonas hominis
Species Size (Length) Shape Number of Nuclei Other Features
4-10 mm.
Usual range, 6-8 mm.
Elongated or
oval.
1-4, usually 2 lying
at opposite ends of
cyst.
Not visible in
unstained mounts.
Resembles E. nana
cyst.
Fibrils or flagella are
usually not seen.

113. Retortamonas intestinalis
Species Size (Length) Shape Motility
Number of
Nuclei
Number of
Flagella*
Other Features
Retortamon
as
intestinalis
4-9 mm.
Usual range, 6-7
mm.
Pear
shaped or
oval.
Jerky. 1
Not visible
in unstained
mounts.
1 anterior.
1 posterior.
Prominent
cytostome
extending
approximately
1/2 length of
body.

114. Retortamonas intestinalis
Species Size (Length) Shape Number of Nuclei Other Features
4-9 mm.
Usual range, 4-7 mm.
Pear shaped or
slightly lemon
shaped.
1.
Not visible in
unstained
mounts.
Resembles
Chilomastix cyst.
Shadow outline of
cytostome with
supporting fibrils
extends above
nucleus.

115. intestinal & urogenital protozoa
Amebae
Blastocystic hominis
Flagellates
Dientamoeba fragilis
Giardia lamblia
Chilomatrix mesnili
Pentatrichomonas hominis
Trichomonas vaginalis
Other flagellates:
Enteromonas hominis
Retortamonas intestinalis
Trichomonas tenax
Ciliates
Balantidium coli
Coccidia
Isospora belli
Sarcocystis sp.
Cryptosporidium sp.
Cyclospera cayetanensis
Microsporidia

116. Balantidium coli

117. Balantidium coli
Species Size Shape Motility Number of Nuclei Other Features
Trophozoite 50-70 mm or
more.
Usual range, 40-
50 mm.
Ovoid with
tapering anterior
end.
Rotary, boring. 1 large, kidney
shaped
macronucleus.
1 small micronucleus
immediately adjacent
to macronucleus.
Macronucleus
occasionally visible in
unstained
preparations as
hyaline mass.
Body surface
covered by spiral,
longitudinal rows
of cilia.
Contractile
vacuoles are
present.
Cyst 45-65 mm. Usual
range, 50-55 mm.
Spherical or oval. 1 large macronucleus
visible in unstained
preparations as
hyaline mass.
Macronucleus and
contractile vacuole
are visible in
young cysts.
In older cysts,
internal structure
appears granular.

118. intestinal & urogenital protozoa
Amebae
Blastocystic hominis
Flagellates
Dientamoeba fragilis
Giardia lamblia
Chilomatrix mesnili
Pentatrichomonas hominis
Trichomonas vaginalis
Other flagellates:
Enteromonas hominis
Retortamonas intestinalis
Trichomonas tenax
Ciliates
Balantidium coli
Coccidia
Isospora belli
Sarcocystis sp.
Cryptosporidium sp.
Cyclospera cayetanensis
Microsporidia

119. Isospora belli

120. Isospora belli
 DX
 UNSPORULATED OOCYSTs
direct wet mounts
concentration techniques
acid-fast stain

121. Isospora belli
Size Shape Motility Number of Nuclei Other Features
Oocyst: 25-30 mm.
Usual range, 28-
30 mm.
Ellipsoidal Nonmotile Usual diagnostic stage is
immature oocyst with
single granular mass
(zygote) within.
Mature oocyst contains 2
sporocysts with 4
sporozoites each.

122. Sarcocystis sp.

123. Sarcocystis sp.
 DX
 SPORULATED SPOROCYSTS
direct wet mounts
acid-fast stains

124. Sarcocystis sp.
Species Size Shape Motility
Number of
Nuclei
Other Features
Sporocyst1 Oval Nonmotile Mature oocysts with
thin wall collapsed
around 2 sporocysts or
free fully mature
sporocysts with 4
sporozoites inside are
usually seen in feces.
hominis 13-17 mm. Usual
range, 14-16 mm.
suihominis 11-15 mm.
Usual range, 12-13
mm.

125. Sarcocystis sp.
wet mount viewed in uv microscopy.
cyst in undercooked meat

126. Cryptosporidium sp.
Cryptosporidium

127. Cryptosporidium sp.
 DX
 concentration methods
 acid-fast stain:
MODIFIED COLD KINYOUN METHOD
deep fuscia
 commercial immunofluorescent & EIA
reagents

128. Cryptosporidium sp.
Species Size Shape Motility
Number of
Nuclei
Other Features
Cryptosporidium Oocyst: 3-6 mm.
Usual range, 4-5 mm.
Spherical or
oval.
Nonmotile Mature oocyst
contains 4 "naked"
sporozoites.
No sporocysts are
present.

129. Cyclospera cayetanensis
Cyclospera cayetanensis

130. Cyclospera cayetanensis
 DX: unsporulated oocysts
 direct wet mount
 trichrome stain
 UV epifluorescence
 modified acid-fast stain
 auramine-o stain

131. intestinal & urogenital protozoa
Amebae
Blastocystic hominis
Flagellates
Dientamoeba fragilis
Giardia lamblia
Chilomatrix mesnili
Pentatrichomonas hominis
Trichomonas vaginalis
Other flagellates:
Enteromonas hominis
Retortamonas intestinalis
Trichomonas tenax
Ciliates
Balantidium coli
Coccidia
Isospora belli
Sarcocystis sp.
Cryptosporidium sp.
Cyclospera cayetanensis
Microsporidia

132. Microsporidia
NO reservoir hosts identified!
merogony

133. Microsporidia
 DX
 tissue examination
routine light & electron microscopy
 stool specimens
modified trichrome staining method (WEBER)
Fluorochrome stain
Uvitex 2B, Calcoflour white

134. Microsporidia
 Enterocytozoon bieneusi
 Light microscopy photographs of
stained stool smears
Quick-Hot Gram Chromotrope stain Weber stain

135. Microsporidia
 Enterocytozoon bieneusi
mature spore.
 double rows of polar tubule coils in
cross section
electron micrograph.
 Encephalitozoon intestinalis
spores and developing forms
inside septated parasitophorous
vacuole.

136. Microsporidia
Scanning electron micrograph of a microsporidian spore with an
extruded polar tubule inserted into a eukaryotic cell.
The spore injects the infective sporoplasms through its polar tubule.