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

138 Manual of basic techniques for a health laboratoryFig. 4.63 Transferring the sample toa slideFig. 4.64 Fasciola hepatica eggT: thickening; O: operculum.Fasciola hepatica (Fig. 4.64)Size: 130–145mm.Shape: oval with rounded poles.Shell: smooth and fine with a double line.Content: a mass of large indistinct cells with clear, granular nuclei (adjust the focus).Colour: ranges from yellow to dark brown.Other features: finely marked operculum at one pole; the cell wall may be visiblyretracted. Thickening of a small part of the cell wall at the other pole.Only small numbers of eggs are found in the stools (a search can be made byduodenal aspiration in doubtful cases).Fasciolopsis buski (Fig. 4.65)Very similar to the eggs of Fasciola hepatica (see Fig. 4.64), but usually present ingreater numbers in the stools.Size: 125–140mm.Shape: oval.Shell: thinner than F. hepatica, single line, with a marked thickening of the wall atthe opposite pole to the operculum.Operculum: slightly smaller than F. hepatica.Content: cells may be shiny with one clear cell in the centre of the egg.Fig. 4.65 Fasciolopsis buskieggT: thickening;O: operculum.Heterophyes heterophyes (Fig. 4.66)Similar to the eggs of Clonorchis sinensis (see Fig. 4.49).Size: 25–30mm.Shape: more oval than C. sinensis; the operculum does not overlap.Shell: slightly thicker than that of C. sinensis.Boss: tiny and wart-shaped, at the wider end of the egg; not always visible.