Pathophysiology Giardiasis is an infection that affects the gastrointestinal tract caused by the parasite, Giardia lamblia, which is also known as Giardia intestinalis. Giardiasis is most commonly spread by contaminated water or food or by direct contact from person to person. In the world, there is an estimated 200 million people are affected by giardiasis. In the United States, there have been over a 120 …show more content…
outbreaks of giardiasis since 1964 (CDC, 2015). The parasite the causes giardiasis, G.
lamblia, is a single celled organism that was formerly classified as an animal in the animal kingdom. As a parasite, it is pear shaped with four flagella extending from its body for easy movement. G. lamblia has a two stage life cycle that can be directly spread to humans without a transitional host. The cycle of the infection is initiated when a human swallows the parasite either through contaminated water of food in the oral cavity. The parasite is covered in a cyst, which is protective shell that surrounds the organism offering protection and allows it to survive when it is outside an animal or human host. It takes approximately 10 to 15 cysts of G. lamblia for a person to swallow in order to be infected. The cyst is oval shaped and consists of a smooth wall. When the cyst reaches inside the body, it passes through the digestive
tract