ABSTRACT
I. BACKGROUND Giardia is a flagellated protist that belongs to the order Diplomonadida (two karyomastigonts, eight flagella, two nuclei, and no mitochondria or Golgi) and the family Hexamitidae (along with the mole parasite Spironucleus muris and the free-living organism Hexamita inflata). The assignment to the family Hexamitidae was based on morphological criteria, but is also supported by molecular phylogenies (1,2).
