Giardia, the endoparasite

Giardia is one of the endoparasite which lives inside the alimentary canal of men and other vertebrates. This is the unicellular protozoan which comes under the class ciliata. Giardia lambla or Giardia intestinalis is a parasite in the small intestine and colon of men. It remains attached in masses to the mucus membrane from where it absorbs food consisting mainly of mucus.Occasionally the parsite invades the bile ducts and gall bladder.Other species of Giardia are parasites in the intestine of vertebrates.
Giardia has an elliptical body which is bilaterally symmetrical. The dorsal side is convex, but the ventral side is flat or may be convex.. The anterior end is rounded and the posterior end is tapering.In the anterior half of the ventral surface is a concave sucking disc for attachment to the host.There are two vesicular nuclei and four pairs of long flagella.Passing through teh cytoplasm from the anterior to the posterior end are two parallel ,flexible, needle like axostyleswhich support the body. The nuclei are attached by fibrils to the axostyles. Just behind he sucking discs is a deep staining parabasal body.
   Giardia prevents absorption of fats by the host inside the body of which it lives. The unabsorbed fat causes diarrhoea.It also forms oval thick-walled cysts. Cyst undergoes the division of nuclei inside it as a result of which four nuclei  are formed. The cysts pass out with the faeces and remain infective for about ten daysor more. The parasites can be removed by the treatment of the disease by the help of antimalarial drugs like chloroquin ans antrebrin.