Figure 1: (a) Vacuolar forms of Blastocystis having a large centrally placed vacuole showing extensive variation in size (arrows), (b) Granular forms with distinct granules filling the central body, (c) Amoeboid form with characteristic pseudopodia, (d) Cyst forms. Note the smaller size and the characteristic refractile cyst wall surrounded by loose irregular outer coat. Bar-10 μm. Reproduced from Kevin S. W. Tan (reference 1) with permission