SPECIALIZED SURFACE ADAPTATIONS OF GIARDIA-LAMBLIA

Although Giardia lamblia trophozoites were first described by Von Leeu wenhoek in his own diarrheic stool, relatively little is known of the basic biology of this common parasite or the pathophysiology of giardi asis. In particular, there is little specific information about tropho zoite properties that cause diarrhea, as neither toxins nor convention al virulence factors have been identified. Therefore, parasite adaptat ions that promote cyst survival in the external environment and infect ion and trophozoite persistence in the small intestine, may be viewed as key virulence properties. This review focuses on unusual surface st ructures of the trophozoite and cyst forms that enable Giardia to be s uch a successful parasite.