Scanning Electron Microscopy of the Denticles and Eggs of Ascaris lumbricoides and Ascaris suum
Morphological differences between Ascaris of human and porcine origins have been difficult to detect. Sprent has distinguished the two species by the characteristics of the denticles observed by light microscopy. The present study is concerned with the differences in morphology of the denticles and with the examination of the ova of the two species as revealed by scanning electron microscopy.Hospital and slaughter house specimens were acquired locally, fixed in phosphate buffered paraformaldehyde and stored in 70% ethanol overnight. Preparative procedures for scanning electron microscopy were as previously reported. Specimens were examined in a JEOL JSMU-3 scanning electron microscope.The denticles of Ascaris suum are regular in distribution and conoid in shape (Fig. 1, A and B). Each denticle is cuspid; no multiple cusps were observed. The “molar teeth” forms previously described probably result from observations of cusps from which adhering debris was not removed in preparation.