Blastocystis is a common intestinal protistan parasite with global distribution. Blastocystis is a species complex composed of several isolates with biological and morphological differences. The surface coats of Blastocystis from three different isolates representing three subtypes were analyzed using scanning electron microscopy. This structure contains carbohydrate components that are also present in surface glycoconjugates in other parasitic protozoa. Electron micrographs show variations in the surface coats from the three Blastocystis isolates. These differences could be associated with the differences in the pathogenic potential of Blastocystis subtypes. Apart from the surface coat, a plasma membrane-associated surface antigen has been described for Blastocystis ST7 and is associated with programmed cell death features of the parasite.
Keywords: Blastocystis; subtypes; surface coat.