Giardia
Giardia (Lamblia intestinalis, Giardia lamblia) - unicellular parasitic animal organisms belonging to the class of flagellates (Mastigophora), causative agents of giardiasis. The disease manifests in various forms: from intestinal with a diarrheal syndrome and other dysfunctions of the gastrointestinal tract and hepato-biliary system, to nervous, characterized by headaches, irritability, weakness, urticaria, as well as may manifest in various types of allergic reactions. Giardia can exist in two forms: vegetative (in the host's body) and cystic. Human infection occurs through ingestion of cysts, including from water into which they enter with
by the feces of an infected individual (parasite carrier)
Source: "SANITARY-PARASITOLOGICAL ASSESSMENT OF THE EFFICACY OF WATER DISINFECTION USING ULTRAVIOLET RADIATION. METHODICAL GUIDELINES. MU 3.2.1757-03"
(approved by the Chief State Sanitary Doctor of Russia on September 28, 2003)