Cholecystolithiasis Is Associated with Clonorchis Figure 6. C. sinensis eggs with morphologic changes under SEM (original magnification, 63000). a, b, eggs were without operculum, and adhered to or wrapped with bilirubinate granules or mucoid matter; c, d, eggs were depressed, and adhered to bilirubinate granules, calcium carbonate crystals or mucoid matter; e, f, eggs had a shedding texture or their operculum had split from the shell. doi:10.1371/journal.pone.0042471.g006 from a comparison of patients with and without C. sinensis infection [18–20]. We think that the two opposing conclusions may be due to the difference in the types of samples analyzed and in the experimental methods employed (e.g. diagnosis of C. sinensis infection). Remarkably, the egg-positive stones were mainly pigment stones. These results suggest that although C. sinensis infection may not necessary lead to increased incidence of cholecystolithiasis [18–20], it is positively associated with high proportion of pigment stones. It remains to be investigated PLoS ONE | www.plosone.org 8 August 2012 | Volume 7 | Issue 8 | e42471