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1. Giardia lamblia
• Cyst:
• Size 10-12ϻm
• Oval
• 4 nuclei
• Fibrils longitudinally in cyst
• Cytoplasm often retracts from
portion of cell wall
• Trophozoite
• Size 10-15ϻm
• Pear shaped
• Falling leaf motility
• 2 nuclei
• Flagella

2. Trichomonas vaginalis
• Flagellate
• Sexually transmitted
• Causes vaginal inflammation and
itching
• Diagnosis is by observing
trophozoites in direct wet mount
from vaginal swab, urine or
prostatic secretions
• 1 nucleus, small karyosome
• Unevenly distributed chromatin
• Size 30ϻm

3. Hemoflagellates
• All have kinetoplast which is a mitochondrium containing DNA
• Have a variety of stages in humans and insect vectors
• Trypanosoma and Leishmania
• Amastigote:
• Oval, 2-5ϻm, nucleus, Kinetoplast, axoneme & no external
flagellum
• Promastigote:
• Elongated with central nucleus. Anteriorly located
kinetoplast and axoneme. Flagellum extending from
anterior end
• Epimastigote:
• Kinetoplast closer to the nucleus and small undulating
membrane with axoneme the flagellum
• Trypomastigote:
• Kinetoplast at posterior end and undulating membrane and
exoneme extending the entire length emerging as a
flagellum at anterior end.

4. Hemoflagellates
• Leishmania have only
amastigote and promastigote
stages
• Trypanosoma may have all 4

5. Leishmania
• Transmitted by sand flies
• Infections of monocyte-
macrophage system with
intracellular amastigotes
• Can cause Cutaneous or visceral
Leishmaniasis
• Divided into new world and old
world

6. Leishmania
• Cutaneous leishmaniasis of the old
world
• South Europe, Northern Africa,
Middle East, Iran, Afghanistan,
Southern Russia and some parts of
central Africa
• L. tropica, L.major, L.aethiopica (more
aggressive)
• Cutaneous leishmaniasis of the
new world
• Central and South America
• L.braziliensis, L.Mexicana, L.peruviana

7. Leishmania
• Visceral leishmaniasis (kala-
azar)of the old world or new
world.
• Fatal if left untreated
• Fever, weight loss, enlargment of
liver and spleen, anemia
• Brazil, East Africa and India
• Mucocutaneous
• Leads to partial or total distruction
of mucous membranes of nose,
mouth and throat
• Bolivia, Brazil, Ethiopia and Peru

8. Leishmania
• Diagnosis: Amastigotes in
smears, biopsies (Giemsa stain)

9. Trypanosoma
• African trypanosomiasis is caused by
Trypanosoma brucei
• Sleeping sickness: CNS involvement,
confusion fatigue, death
• Acute febrile illness: Death before CNS
is prominent
• Transmitted by Tsetse fly
• Sub-Saharan Africa
• Patients show high IgM in Blood and
CSF
• Diagnosis is by demonstrating
trypomastigotes in peripheral blood
film or lymph node aspirate stained
with Giemsa

10. Trypanosoma

11. Trypanosoma
• American trypanosomiasis
• Central or South America
• Chagas disease (fever, headache, rash,
diarrhea, vomiting, swelling or sore
near bite site, enlarged glands)
• Caused by Trypanosoma cruzi
• Transmitted by reduviid bug (kissing
bug)
• Can be transmitted by blood
transfusion
• Diagnosis by demonstrating
trypomastigotes in peripheral blood

12. Trypanosoma

13. Toxoplasma gondii
• Coccidian
• Obligate intracellular parasite
• Found in domestic and wild animals especially carnivores
• May cause serious congenital and ocular infections
• Immature oocysts are passed in cat feces and mature to infective stage in the environment in 2 to
21 days
• Ingestion by humans where trophozoites infect nucleated cells.
• Proliferation may lead to cell death or formation of tissue cysts containing up to 3000 organisms
• Only trophozoite (tachyzoite) and cyst (bradyzoite) stage occur in humans
• Examination of tissues hematoxylin and eosin stain
• Smears Giemsa stain
• Serology IgG and IgM
• PCR

14. Toxoplasma gondii

15. Toxoplasma gondii
• Tachyzoites (trophozoites)
of T. gondii are approximately 4-8 µm
long by 2-3 µm wide, with a tapered
anterior end, a blunt posterior end
and a large nucleus.
• Cysts are usually spherical in the brain
but more elongated in cardiac and
skeletal muscles. They may be found
in various sites throughout the body
of the host, but are most common in
the brain and skeletal and cardiac
muscles.