**2. Overview and general aspects of giardiasis**

*Giardia* was described and was associated with the symptoms in 1681 for the first time when the Dutchman, Van Leeuwenhoek, found the trophozoites in his own feces; nevertheless, just until 1859, the first report was credited to the Czech Vilém Lambl [1–3]. *Giardia intestinal* is a flagellated protozoon (also known as *G. lamblia* or *G. duodenalis*) and is a tiny and ubiquitous intestinal and/or biliary parasite, which affects mammals, such as humans, pets, and livestock by inhabiting the upper part of the small intestine [4–6]. Frequently, this parasite contaminates water sources worldwide especially in temperate and tropical locations where sanitary conditions are suboptimal; for this reason, giardiasis is the commonest parasitic infection of the gastrointestinal tract, the most important responsible for outbreaks of diarrhea and sporadic endemic disease [7, 8].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
