Graph representing epithelial permeability of Caco-2 monolayers after co-incubation with live cells of Blastocystis ST-7 and ST-4 for 24 h. All strains in ST-7 induced significant increase in flux of dextran–FITC across epithelial monolayer of Caco-2 cells compared with control monolayers (p<0.01). No significant change in permeability was observed in Blastocystis ST-4-infected Caco-2.Within ST-7, an intra-subtype variation in the capability of inducing permeability change was observed. Isolates C, G and H induced much higher permeability increase compared to isolates B and E within the same subtype (p<0.01). **, p<0.01 vs. ST-7 (B, E)-infected cells; ##, p<0.01 vs. ST-4-infected cells; ‡, p<0.01 vs. non-infected cells. Each value represents mean of twelve samples, taken from three independent experiments, four samples from each. Error bars represent the standard errors.