- Giardia lamblia is a unicellular parasite that causes giardiasis in humans. It was first observed by Van Leeuwenhoek in 1681 and named after Alfred Giard. - It exists in two forms - a cyst form which is infective, and a trophozoite form which attaches to the small intestine mucosa. The cyst is ingested and the trophozoite emerges to attach and feed. - Symptoms of giardiasis include diarrhea, flatulence, and greasy stool. The infection is common in children and spreads through contaminated food, water, or direct fecal-oral transmission.

1. lamblia
Prepared by:
NOE P. MENDEZ
CENTRAL MINDANAO UNIVERSITY(CMU)
npolomendez@gmail.com

2. Giardia lamblia
• traveler diarrhea or beaver fever
• unicellular parasite
• Initially found by Van Leeuwenhoek in 1681
• named after Alfred Mathieu Giard (Clinical
Microbiology Review, 2001).

3. Domain: Eukarya
Kingdom: Protista
Phylum: Sarcomastigophora
Class: Zoomastigophora
Order: Diplomonadida
Family: Hexamitidae
Genus: Giardia
Species: G. lamblia

4. Giardia lamblia
Mode of infection:
Contaminated food or water
Flies and food handlers
Faeco-oral Trophozoite
Causes : Giardiasis in man especially children.
Geological Distribution: Cosmopolitan.
Habitat : Duodenum, upper part of small intestine, bile ducts and gall
bladder as trophozoites attached to the mucosa.
D.H: man R.H: animals
Infective stage : the cyst.
Cyst

6. Giardia lamblia
Morphology of Cyst stage:
Average size 12 X 7 µ
Oval with well defined cyst wall
Four nuclei present usually at one pole.
Includes: axostyle – parabasal bodies – remnants
of flagella

7. Giardia lamblia
Morphology of Trophozoite stage:
Average size 15 X 8 µ
Pear shaped (broad anteriorly –tapering posteriorly)
Convex dorsally –flat ventrally with bilobed anterior
concavity (sucking discs) for attachment.
Motility by 4 pairs of flagellae (similar to a falling leaf)
Two oval nuclei with central karyosome.
Two axostyle traversing the body
Two rod-shaped parabasal bodies across the
axostyle

9. Binary fission
Enter with food
Pass in stool
Duodenal mucosa
cyst
trophozoite

11. • Giardia infected patients complain of
diarrhoea and flatulence.
• Stool of Giardia infected patients is light-
coloured and greasy.
• G. lamblia infection is common in children.
• Giardia cysts are infective to man.

12. Muller, J., G. Ruhle, N. Muller, JF. Rossignol and A. Hemphill.
2006.In Vitro Effects of Thiazolides on Giardia lamblia
WB Clone C6 Cultured Axenically and in Coculture with
Caco2 Cells. American Society for Microbiology.50:1
(162–170).
Mohamed, R. 2003. Giardia lamblia.