Surface Topography of Newly Excysted Metacercariae of Thai Paragonimus Species

Abstract

Abstract

The surface topography of newly excysted metacercariae of five species of Thai lung flukes:Paragonimus westermani, P. siamensis, P. heterotremus, P. harinasutai and P. bangkokensis aredescribed. The findings showed that the metacercarial bodies were ellipsoidal or oval in shape. Theirsurfaces were armed almost entirely with tegumentary spines. These spines were single-pointed andwell developed in the antero-ventral region. Three morphological types of papillae were observed,as follows: a) large-domed papillae on the lips of the oral and ventral suckers; b) small-domed papillaeover the entire body, persistently distributed around both suckers; and c) pit-type papillae whichwere limited to the oral sucker area.

Keywords: Paragonimus, metacercariae, topography, scanning electron microscopy, Thailand