giardia features

1. Giardia Lamblia

2. Giardia Lamblia
• The genus Giardia belongs to the class
mastigophora (flagellates).
• It is one of the most primitive eukaryotes.
• G. lamblia (also called intestinalis or duodenalis)
is the species infecting humans.
• It occurs all over the world.
• Habitat
• Duodenum and upper part of jejunum

3. Morphology
G. lamblia is found in following 2 stages:
• Trophozoites
• Cysts

4. Trophozoites &Cysts
• Trophozoite: pear shaped, symmetric and 10-20m long by 6-
8m wide, 4 pairs of flagella with bilateral symmetry; 2 nuclei
with central karyosomes and 2 axistyles.
• Large concave sucking disk on anterior ventral surface.
• Trophozoites found in upper 1/3rd of small intestine.
• When swept into the colon they encyst.
• Cysts: are 8-14m long, ellipsoid, contain 2-4 nuclei and have
a thick (0.3 m) wall.
• Ruminant flagellae and margins of sucking disc lie inside
cytoplasm
• They are passed in stools

6. Cysts are formed in bowel
L
I
F
E
C
Y
C
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Cysts passed with stools
Ingestion of edibles & water
contaminated with cyst
Acidic pH of stomach initiates excystation
Which completed in duodenum
thus release trophozoites
Multiply by binary fission
It can also localize in biliary tract

7. Life Cycle

8. Pathogenesis
•The production of diarrhea, and occasionally
malabsorption, is the result of a complex interaction of
Giardia with the host,
•Infection occurs after oral ingestion of as few as 10 to 25
cysts.
•After excystation, trophozoites colonize and multiply in
the upper small bowel
•Adherence of G. lamblia in the human gut may be via the
disk.
•It may cause a disturbance of intestinal function, leading
to malabsorption of fat.

9. Pathogenesis cotd….
•Disruption of the brush border
•Mucosal invasion
•Stimulation of an inflammatory infiltration
leading to fluid and electrolyte secretion and
occasionally to villous changes

10. Giardia Lamblia clinging to the wall of a duodenal villus.

11. •Acute onset of diarrhea
•Abdominal cramps, bloating, and flatulence
•Feelings of malaise, nausea, and anorexia
•May complain of sulfuric belching
•Vomiting, fever, and tenesmus occur less
commonly.
•Stools may be profuse and watery, but later they
are commonly greasy, and foul-smelling and may
float
•Steatorrhea
Clinical Features

12. Laboratory Diagnosis
• Microscopic examination
• Wet, saline mounts: falling leaf motion, fibrils
present, and nucleic characteristics.
• Biopsy tissue/duodenal aspirate stained by
trichrome or Giemsa stain.
• Enzyme immunoassay and fluorescent- anitbody
monoclonal antigen detection systems
•Treatment
•Metronidazole
•Quinacrine
•Furazolidone
•Tinidazole

13. PREVENTION
The prevention of giardiasis requires proper
handling and treatment of water
 Good personal hygiene on an individual basis
Chlorination of water
Bringing water to a boil is sufficient to kill all
protozoal cysts; at high altitudes, boiling for longer
periods may be necessary