Giardia Iamblia

Abstract

The flagellated protozoan Giardia lamblia (also known as G.intestinalis or G.duodenalis) is the causal organism of one of the most common intestinal infections worldwide. The organism exists as a free-living trophozoite and as a thin-walled cyst form. The trophozoite is pear-shaped and dorsally convex with a concave ventral sucking disc, and a characteristic arrangement of nuclei and other organelles which results in a face-like appearance. Infection is acquired by ingesting the cysts, usually in faecally contaminated water or food, although person-to-person spread also occurs. The disease is more common in areas of poor sanitation. Numerous large waterborne outbreaks in the United States, Europe and elsewhere have been described. Although humans are the main reservoir of infection, a variety of animals may carry Giardia spp., and are considered by many to play a role in the epidemiology of the infection.