This parasite is transmitted via person to person, waterborne, foodborne, and zoonotic (i.e., transmission of the pathogen from infected animals to humans) routes. Several drinking water-associated outbreaks wereFigure 1.6 Immunofluorescece images of Giardia lamblia cysts (A) and Cryptosporidium parvum oocysts (B). Courtesy of H.D.A. Lindquist, U.S. EPA. (For a color version, see the color plate section.)