Details of identification features of Diagnostic stage

1. Lab diagnosis of Trematodes,
Blood Flagellates,Plasmodium
and Protozoans
Prepared by: Faiz Ullah 2nd batch MLT

2. T. b. rhodesiense and T. b.
gambiense
T. b. rhodesiense and T. b. gambiense
trypanosomes
● Trypanosomes measure 13–42 micro meter in
length and may show a variety of forms (pleomorphic).*
* In the early stages of acute African trypanosomiasis,
long slender trypanosomes (often seen dividing) can be
found. In the later stages, intermediate and
trypanosomes, some having no free flagellum,may be
seen.
● Single flagellum arises from the kinetoplast.
It extends forwards along the outer margin of undulating
membrane and usually beyond it as a free anterior
flagellum.

3. T. b. rhodesiense and T. b.
gambiense
● Small dot-like kinetoplast stains darkly.
● Nucleus stains dark-mauve and is usually
centrally placed but posterior nuclear forms
may also be seen.
● Cytoplasm stains palely and contains granules.
Note: Microscopically, the trypanosomes of
T. b. rhodesienseand T. b. gambienselook the same.

4. T. b. rhodesiense and T. b.
gambiense
Morphology of a trypanosome of
T.b.gambiense or
T.b.rhodesiense
Left: T.b.gambiense/T.b.rhodesiensein thick
blood film.
Right: T.b.gambiense/T.b.rhodesiense in thin
blood film.

5. T. cruzi trypanosomes
● Usually C-shaped, measuring 12–30 micro meter in
length with a narrow membrane and freeflagellum.
● Has a large, round to oval, dark-red staining kinetoplast
at the posterior end.
● Nucleus is centrally placed and stains redmauve.
Note: Occasionally slender forms of T. cruzican be seen
which have an elongated nucleus, subterminal
kinetoplast, and shorter free flagellum.

6. T. cruzi trypanosomes
Right: T.cruziin Giemsa stained thin blood film.
Left: T.rangeli.

7. Amastigotes of Leishmania
species
Structurally, the amastigotes of Leishmania
species that cause VL, CL and MCL are similar.
There are variations in size between species.
● Small, round to oval bodies measuring 2–4 micro meter
● Can be seen in groups inside blood monocytes (less
commonly in neutrophils), in macrophages in aspirates
or skin smears, or lying free between cells.
● The nucleus and rod-shaped kinetoplast in each
amastigote stain dark reddish-mauve.
● The cytoplasm stains palely and is often
difficult to see when the amastigotes are in groups.

8. Amastigotes of Leishmania
species
Leishmaniaamastigotes in
monocyte in a Giemsa
stained blood film
Giemsa stained amastigotes of
L.donovani.
Right:As seen in bone marrow.
Left: As seen in splenic aspirate.

9. Plasmodium Species
• The appearance of each of the four species of plasmodia
that infect humans is sufficiently different to allow their
differentiation in stained smears
• The parasitized erythrocyte in P. vivax and P. ovale
infections is pale, enlarged, and contains numerous
Schüffner’s dots
• All asexual stages (trophozoite, schizont, merozoite)
may be seen simultaneously
• Cells infected by P. ovale are elongated and frequently
irregular or fimbriated in appearance
• In P. malariae infections, the RBCs are not enlarged and
contain no granules. The trophozoites often present as
“band” forms, and the merozoites are arranged in
rosettes around a clump of central pigment.
• In P. falciparum infections, the rings are very small and
may contain two chromatin dots rather than one

10. Plasmodium Species
• There is often more than one parasite per cell, and
parasites are frequently seen lying against the margin of
the cell
• Intracytoplasmic granules known as Maurer’s dots may
be present but are often cleft shaped and fewer in
number than Schüffner’s dots
• Schizonts and merozoites are not present in the
peripheral blood. Gametocytes are large and banana
shaped

11. Plasmodium Species

12. Trophozoites - Plasmodium falciparum: Early trophozoites have the
characteristic signet ring shape. Also, unique to P. falciparum is the
presence of multiple trophozoites in one cell.

13. Trophozoites - Plasmodium vivax: Red blood cells infected by
P. vivax are often larger than uninfected red blood cells.
They approximately 1.5 times the size of a normal cell

14. Trophozoites - Plasmodium malariae: Characteristic trophozoites of
P. malariae showing the ring shape and the tendency of infected cells
to be of normal or smaller size (arrows).

15. Gametocyte - Plasmodium falciparum: The gametocytes of
P. falciparum have a crescent or banana shape.

16. Gametocyte - Plasmodium malariae: The gametocytes of P. malariae havea round
shape about the size of red blood cells. They have a fine granular appearance.

17. Gametocyte - Plasmodium ovale: A round gametocyte that is larger
than normal red blood cells. It has a granular appearance as well as Schuffner's dots

18. Schizont - Plasmodium malariae: A schizont containing merozoites (6 to 12)
giving a coarse granular appearance

19. Schizont - Plasmodium vivax: A schizont showing the large
number of merozoites typical of this species (16-24). Also note the
larger size compared to a normal red blood cell

20. A red blood cell showing the Schuffner's dots characteristic of cells
infected by Plasmodium vivax and Plasmodium ovale

21. Egg of S. mansoni
● It is pale yellow-brown, large, and oval,
measuring about 150*60 micro meter.
● Has a characteristic side (lateral) spine.
Note:Sometimes the spine may appear terminal like
that of an S. haematobiumegg but if the egg is rolled
over by pressing gently on the cover glass the spine
will be seen to be lateral.
● Contains a fully developed miracidium.

22. Egg of S. japonicum
● It is colourless or pale yellow-brown, large and round to
oval, measuring about 90*65 micro meter.
● A very small hook-like spine (rudimentary spine) can
sometimes be seen projecting from the egg wall but
often it is hidden by faecal debris and red cells.
● Contains a fully developed miracidium.

23. Egg of S. mansoni & S. japonicum
Egg of S.mansoni with lateral spine. Egg of S.japonicum. Rudimentary spine is not
visible.

24. Egg of S. haematobium
● It is pale yellow-brown, large and oval in
shape, measuring about 145*55 micro meter.
● Has a characteristic small spine at one end
(terminal spine).
● Contains a fully developed miracidium.
Note: Sometimes the miracidia hatch from the eggs and
can be seen ‘swimming’ in the urine
● A living egg (in fresh unpreserved urine) shows what is
called flame cell movement, i.e. flickering of the
excretory flame cells

25. Egg of S. haematobium
S.haematobiumegg and red
cells in urine
Position
of flame cell

26. Egg of F. hepatica
● It is yellow-brown, large and oval. F. hepatica eggs
measure 130–145*70–90micro meter. F. gigantica eggs
are larger, measuring 156–197*90–104 micro meter.
● Has an indistinct operculum (lid).
● Contains an unsegmented ovum
surrounded by many yolk cells.
Note: Morphologically Fasciolaeggs resemble
those of Fasciolopsis buski and Echinostoma species.

27. Egg of F. hepatica
Eggs of F.hepatica.

28. Egg of F. buski
● It is yellow-brown, large and oval, measuring 130–
154*78–98 micro meter.
● Has a small operculum (lid) which is usually
difficult to see.
● Contains an unsegmented ovum surrounded by yolk
cells.
Note: Morphologically the eggs of F. buskiresemble
those of F. hepatica, F. gigantia(similar but smaller), and
Echinostomaspecies.

29. Egg of F. buski
Egg of F.buski.

30. Trophozoite of E. histolytica
● Average size is about 25*20 micro meter
● Shows active amoeboid movement (directional)
in fresh warm specimen.
● In dysenteric specimens, the amoebae
contain ingested red cells. This is diagnostic
of E. histolytica.
● Single nucleus is present which has a central
karyosome (not always visible).

31. Trophozoite of E. histolytica
Morphology of E.histolyticatrophozoite

32. Cysts of E. histolytica/E. dispar
● Round, measuring 10–15 micro meter
● Contain, 1, 2 or 4 nuclei with a central karyosome
(special staining techniques are required to show details
of nuclear structure).
● Chromatoid bodies (aggregations of ribosomes) can be
seen particularly in immature cysts. They do not stain
with iodine but can be stained with Burrow’s stain or
Sargeaunt’s stain

33. Cysts of E. histolytica/E. dispar
Morphology of immature and matureE.hisolytica
/E.disparcysts.

34. Trophozoite of G. lamblia
● Small pear-shaped flagellate with a rapid tumbling and
spinning motility, often likened to a falling leaf.
● Measures 12–15*5–9 micro meter
● Has a large concave sucking disc on the ventral surface
(attaches trophozoite to the intestinal mucosa).
● It has four pairs of flagella, two axonemes,and two nuclei
which stain well (Giemsa or Field’s technique).
● A single or two curved median bodies are
present (function unknown).
T

35. Cyst of G. lamblia
● Small and oval measuring 8–12 * about
6 micro meter
● Internal structures include four nuclei grouped at one end
(sometimes difficult to see), axonemes, median bodies,
and remains of flagella. These structures can be seen in
unstained preparations but are more clearly defined in
an iodine preparation.

36. Trophozoite & Cyst of G. lamblia
Morphology of G.lamblia. Left: cyst.
Right: trophozoite

37. Cyst of B. coli
● Large, round, thick walled, measuring 50–60 micro meter
in diameter.
● Cilia (inside wall) can sometimes be seen in younger
cysts.
● Macronucleus stains well with iodine.

38. Trophozoite of B. coli
● Large, easily seen oval shaped ciliate with a rapid
revolving motility, measuring 50–200*40-70 micro meter
● With careful focusing, the beating cilia can be seen
particularly in the region of the funnel-shaped cytostome.
● Often contains ingested red cells.
● A large macronucleus may be seen. A very small
micronucleus lies close to the macronucleus but this can
only be seen instained preparations.
● One of two contractile vacuoles may be
visible.

39. Trophozoite & Cyst of B. coli
Morphology of B.colicyst &
B.coli cyst in saline
preparation
B.coli trophozoite in saline preparation.

40. Trichomonas vaginalis

41. Trichomonas vaginalis