Presented By:
Dr. Shaymaa Abdalal
Medical Parasitology Demonstrator
INTESTINAL PROTOZOA
 Numerous protozoa inhabit the gastrointestinal tract of humans .
 Entamoeba histolytica can become a highly
virulent and invasive organism that causes a
potentially lethal systemic disease.
 Giardia lamblia can cause severe acute
diarrhea which may lead to a chronic diarrhea
and nutritional disorders
INTESTINAL PROTOZOA
 Intestinal protozoa are transmitted by the
fecal-oral route .
 exhibit similar life cycles consisting of a cyst
stage and a trophozoite stage
INTESTINAL PROTOZOA
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Giardia lamblia
Disease:
GIARDIASIS
Distribution:
worldwide distribution and is the most common
protozoan isolated from human stools.
Giardia lamblia
 Definitive host : man
 Habitat:
intestine.
upper
portions
 Infective stage: cysts.
of
the
small
Giardia lamblia trophozoite
Characteristic features :
 Two nuclei (Nu).
 Central karyosomes (k).
 median bodies (MB).
 Axonemes (Ax) .
 Four pairs of flagella (Fg).
 An adhesive disk (AD).
www.tulane.edu/~wiser/protozoology/notes/intes.html
Giardia lamblia trophozoite
Morphology:
 Size : 12-15 X 5-10µm.
 Shape: Pear or Tear Drop
www.tulane.edu/~wiser/protozoology/notes/intes.html
Giardia lamblia trophozoite
Giardia lamblia cyst
Characteristic features :
 Four nuclei (Nu).
 Axonemes (Ax) .
 Median bodies (MB).
 Well-defined wall (CW)
Giardia lamblia cyst
Morphology :
 Size : 11-14X 6-10µm.
 Shape: Oval
Giardia lamblia cyst
Entamoeba histolytica
Disease:
amebiasis or amebic dysentery.
Distribution:
 found throughout the world, they are more
common in tropical countries or other areas
with poor sanitary conditions.
Entamoeba histolytica
 Definitive host : man
 Habitat: large intestine.
 Reservoir: no animal reservoirs.
 Infective stage: cysts.
Entamoeba histolytica trophozoite
Characteristic features :
 a finger-like
pseudopodium (psd) .
 the ectoplasm (ecto).
 cytoplasm has a granular
appearance the endoplasm (endo).
 a glycogen vacuole (vac).
 Nuclear (Nu).
 chromatin and a centrally located
karyosome (ka).
Entamoeba histolytica trophozoite
Morphology :
 Size : 15-30 µm.
 Shape: an amorphous shape .
Entamoeba histolytica trophozoite
Entamoeba histolytica cyst
Characteristic features :
 Chromatoid bodies (cb) .
 1-4 nuclei (Nu).
 a glycogen vacuole (vac) .
Entamoeba histolytica cyst
Morphology :
 Size : 12-15 µm.
 Shape: spherical shape .
Entamoeba histolytica cyst
Malaria
 Malaria is the 5th cause of death from
infectious diseases worldwide (after
respiratory infections, HIV/AIDS, diarrheal
diseases, and tuberculosis) in low-income
countries.
 Malaria is the 2nd leading cause of death from
infectious diseases in Africa, after
HIV/AIDS.
Malaria
Disease:
Malaria
Distribution:
Malaria today is usually restricted to tropical
and subtropical areas
Malaria
 Intermediate Host: man
 Vector (Definitive host) : femaleAnopheles mosquito
 habitat: RBC`s
 Infective stage: sporozoites .
P. vivax
P. Vivax ring stage
Diagnostic Points:
1.Red cells containing parasites
are usually enlarged.
2.Schuffner's dots are
frequently present in the red
cells as shown above.
3.The mature ring forms tend to
be large and coarse.
4.Developing forms are
frequently present.
P. Vivax schizont stage
 schizonts of P. vivax are large and amoeboid.
 Schizont large may almost fill the RBC`s.
 Mature = 12 to 24 merozites.
P. falciparum
P. falciparum ring stage
Diagnostic Points:
 Red Cells are not enlarged.
 Rings appear fine and
delicate and there may be
several in one cell.
 Some rings may have two
chromatin dots.
 Presence of marginal or
applique forms.
 No Trophosoite and
schizont.
P. falciparum gametocyte stage
Gametocytes of P. falciparum. Figs. 27-28: Macrogametocytes
(female); Figs. 29-30: Microgametocytes (male).
Illustrations from: Coatney GR, Collins WE, Warren M, Contacos PG. The Primate Malarias. Bethesda: U.S. Department of Health,
Education and Welfare; 1971.
P. falciparum gametocyte stage
 crescent- or sausageshaped.
 1.5 times the diameter
of an RBC in length.
 remnants of the host
RBC can be seen; this
is often referred to
as Laveran's bib.
P. falciparum gametocyte stage
 Gametocyte of P.
falciparum in a thin
blood smear, showing
Laveran's bib.
Key Morphological Differences
Falciparum
vivax
 numerous rings
 enlarged erythrocyte
 smaller rings
 Schüffner's dots
 no trophozoites or
 'ameboid' trophozoite
schizonts
 cresent-shaped
gametocytes