This document discusses the intestinal flagellate Giardia intestinalis. It describes the two stages of G. intestinalis as trophozoite and cyst. The trophozoite is oval to pear shaped and 9-20μm in length. The cyst is 8-18μm in length and contains 4 nuclei. G. intestinalis has a worldwide distribution and causes giardiasis in humans. It is transmitted through ingestion of cysts from contaminated water or food. Symptoms include diarrhea, abdominal cramps, and malabsorption. Treatment involves medications like metronidazole. Prevention relies on water filtration and hygiene.

1. Intestinal Flagellates
(Gardia intestinalis)
Prepared by:
NOE P. MENDEZ
CENTRAL MINDANAO UNIVERSITY (CMU)
npolomendez@gmail.com

2. INTESTINAL FLAGELLATES
Chilomastix mesnili (non-pathogenic)
Enteromonas hominis (non-pathogenic)
Retortamonas intestinalis (non-pathogenic)
Trichomonas hominis (non-pathogenic)
Dientamoeba fragilis (non-pathogenic)
Giardia intestinalis (pathogenic)

3. Stages of
Intestinal
Flagellates

4. Giardia intestinalis
 Also known as G. duodenalis.
 Diseases: Giardiasis, lambliasis, flagellate diarrhea.
 Geographic distribution: world wide, more prevalence in warm
climates.
 Consist of 2 stages: 1)trophozoite 2)cyst
 Trophozoite: 9-20µm in length, 5-15µm in width, oval to pear
shaped, 2 nucleus,
 Cyst: 8-18µm in length, 7-10µm in width, oval, more eccentric
karyosome, 4 median bodies (mature cyst), 4 nucleus (mature
cyst).

5. G. intestinalis (trophozoite)
 K= karyosome
 Nu=nucleus
 MB=median body
 Fg=flagella
 Ax=axoneme
 AD=adhesive disk

6. Gardia intestinalis under
EM
Trophozoite Stage

7. G. Lamblia (cyst)
Nu=nuclues
K=karyosome
Ax=axoneme
MB=median
body
CW=cyst wall

8. Gardia intestinalis
under EM
Cysts Stage

9. Life Cycle

10. Infective stage: cyst
Acquired by ingestion passage through stomach
small intestine  duodenum  large intestine 
pass in stool  environment.
Duodenum= excystation occurs  trophozoite
multiply itself by longitudinal binary fission
(approximately 8 hours intervals).
Large intestine= encystation occurs.
Both trophozoite and cyst can be found in the feces.

11. Transmission & Pathogenesis
 The most pathogenic intestinal flagellate.
 Distribution: world wide
 Found in the gastrointestinal tracts of a variety of
mammals, including man.
 Habitat: ponds, lakes, stream.
 Resistant to chlorine.
 Filtration is necessary to eliminate contamination.

12. Transmitted via: water, foods (fruits and raw
vegetables), person to person contact (oral-anal
sexual practices).
Incubation period bout 2-3 weeks  get
symptoms: watery foul-smelling diarrhea,
abdominal cramps, flatulence, anorexia, and
nausea.
Also have fat-soluble deficiencies, folic acid
deficiencies, hypoproteinemia with
hypogammaglobulinemia and structural changes in
intestinal villi.

13. Severe cases: get malabsorption syndrome
and steatorrhea, and weight loss.
Patient r often, however asymptomatic.
How d parasite attaches to the intestinal
mucosa? By the sucking disc/adhesive disc
located on the ventral side of the cell.

14. Treatment
Metronidazole
Quinacrine
Tinidazole
Furazolidone
Paromomycin

15. Prevention
 By avoidance of contaminated water.
 Filtration (this parasite resistant to chemicals such as chlorine).
 Protecting water supplies from reservoir hosts such as beavers, muskrats
and voles.
 Exercising good personal hygiene.
 Safe sexual practices.

16. Thank you 