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

146 Manual of basic techniques for a health laboratoryPollen grains and fungus spores (Fig. 4.91)Size: very variable, depending on the geographical area and the local diet.Shape: distinctive geometrical shapes.Other features: distinctive saw-like or rounded projections, etc.4.4.2 Identification of adult helminthsAdult helminths brought to the laboratory for identification may have been foundin stools, in clothing or bed linen, or during a surgical operation.What to examine:— their length— their shape— whether they are flat or segmented— whether they are cylindrical (round)— their internal structure.Fig. 4.90 Plant hairsCommon helminthsAscaris lumbricoides (roundworm) (Fig. 4.92)Length: male — about 15cm, with a curved tail; female — 20–25cm, with a straighttail.Colour: pinkish.Fig. 4.91 Pollen grains and fungus sporesEnterobius vermicularis (pinworm or threadworm) (Fig. 4.93)Length: male — 0.5cm; female — 1cm, with a very pointed tail (males are lesscommon).Colour: white.Pinworms or threadworms are found in large numbers, especially in children’sstools, and are motile. They may also be found in the folds of skin around the anus,where they can be collected with a strip of adhesive cellophane (see section 4.4.1,page 135).Taenia saginata (beef tapeworm) and T. solium (pork tapeworm)Length: total worm, 3–10m, but single mature segments (1–3cm long) or fragmentsof the chain (variable in length) are usually presented for examination.