Most flagellates are free-living but most intestinal flagellates are non-pathogenic for man. Although flagellates are characteristic for member of this group, they are not always visible under the microscope.

Unlike the amoebae, most flagellates move by floggingof flagella which allows it to "swim" move about in fluid environments. Diseases caused by flagellates are mainly due to inflammation and mechanical irritation.



Extracted from: Essentials of Human Parasitology

Giardia Lamblia

(causes Giardiasis)


 Extracted from: Essentials of Human Parasitology


Physiology and Structure:

Its life cycle consists of 2 stages - the trophozite and cyst. The trophozoite is a pear-shaped with 2 nuclei, 4 pairs of flagella, and a suction dish whereby it attaches to the intestinal wall. The oval cyst is thick-walled with 4 nuclei and a Giardia that appears as a face of a man under the microscope.

taken from: https://www.smittskyddsinstitutet.se/diagnostik/urdjur/giardia-intestinalis/?sid=36

Life Cycle:



Extracted from: Essentials of Human Parasitology



Caused by:

Giardia is caused by ingestion of the cyst found in contaminated food and water.

Contaminated water; chlorination does not kill the cysts but filtration removes them. Hikers who drink untreated stream water are frequently affected.


What effect it has on humans:

The trophozoite attaches to the gut wall but does not invade; instead it causes inflammation of the first part of the small intestine which leads to malabosorption of protein and fat.


Treatment, Prevention and Control: