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

128 Manual of basic techniques for a health laboratoryTable 4.5 Helminth species whose eggs are found in stoolsScientific nameAncylostoma duodenaleAscaris lumbricoidesClonorchis sinensisDicrocoelium dendriticum, Dicrocoelium hospesDiphyllobothrium latumDipylidium caninumEnterobius vermicularisFasciola giganticaFasciola hepaticaFasciolopsis buskiHeterophyes heterophyesHymenolepis diminutaHymenolepis nanaMetagonimus yokogawaiNecator americanusOpisthorchis felineusParagonimus westermani aSchistosoma haematobium bSchistosoma intercalatumSchistosoma japonicumSchistosoma mansoniSchistosoma mekongiStrongyloides stercoralis cTaenia saginataTaenia soliumTrichostrongylus (various species)Trichuris trichiuraWorldwideWorldwideSouth-east AsiaWorldwideWorldwideWorldwideWorldwideWorldwideWorldwideEastern and southern AsiaGeographical distributionSouth-east Asia, eastern MediterraneanWorldwideWorldwideEastern and southern Asia, central and eastern EuropeWorldwideEastern and southern Asia, central and eastern EuropeCentral Africa, South America, eastern and southern AsiaAfrica, eastern MediterraneanAfricaEastern and southern AsiaAfrica (south of the Sahara), Central and South America,the CaribbeanSouth-east AsiaWorldwideWorldwideWorldwideAsiaWorldwideaFound mainly in sputum.bFound mainly in urine.cFound mainly as larvae in stools.●●C: semi-decorticated fertilized egg (less frequent).D: semi-decorticated unfertilized egg (very rare).Type A. Fertilized egg with double shell (Fig. 4.45)Size: 45–70mm.Shape: oval or sometimes round.Shell: the two shells are distinct:— the external shell is rough, brown and covered with small lumps(mamillated)— the internal shell is smooth, thick and colourless.Content: a single round granular central mass.Colour: external shell — brown; content — colourless or pale yellow.