Manual of basic techniques for a health laboratory - libdoc.who.int

134 Manual of basic techniques for a health laboratoryFig. 4.49 Clonorchis sinensiseggsB: boss.Clonorchis sinensis (Fig. 4.49)Size: 25–45mm.Shape: distinctive.Shell: fine and smooth but quite thick (double line).Operculum: easily visible at the narrow end of the egg, fitting into a thickened rim ofthe shell.Boss: a small knob at the wide end of the egg.Content: a well-organized ciliated embryo.Colour: shell — yellowish-brown, content — pale yellow.Dicrocoelium spp.Size: 35–50mm.Shape: oval, rather asymmetrical.Shell: thick, smooth and yellow, orange or light brown.Operculum: easily visible.Type A. Eggs in passage 1 (form most often found; Fig. 4.50)Shell: yellow, orange or light brown.Content: an indistinct dark yellow oval mass, often with 1–4 shiny globules.Fig. 4.50 Dicrocoelium sp. egg inpassageO: operculum.Fig. 4.51 Dicrocoelium sp. egg frominfected patientType B. Eggs from infected patient (very rare; Fig. 4.51)Shell: uniform dark brown.Content: a ciliated embryo.Diphyllobothrium latum (Fig. 4.52)Size: 55–80mm.Shape: oval.Shell: smooth and thick.Operculum: scarcely visible when not raised.Boss: very small, at the opposite end to the operculum.Content: a mass of small cells around a large central cell.Colour: pale yellow.Fig. 4.52 Diphyllobothriumlatum eggB: boss;O: operculum.1Observed when the patient has eaten sheep or beef liver infected by the flukes. The eggs of theflukes are not digested and although they appear in the stools, the patient is not infected. Repeatthe examination 8 days later. Tell the patient not to eat liver or liver products in the meantime.