Scanning electron microscopy of cuticular surface of the adults Paragonimus heterotremus in Phitsanulok, Thailand.

Scanning electron microscope observation of surface structure was made on adult Paragonimus heterotremus (Phitsanulok, Thailand) and the surface topography of the anterior end, suckers, body cuticle and papillae was described. The numerous thorn-like tegumentary spines were distributed all over the surface. The spines were well-developed and branched. The papillae were divided into two types: dome-shaped and ciliated. Two pairs of papillae were seen around the lip of the oral sucker, while those around the ventral sucker were not evident.

Surface ultrastructure of newly excysted metacercariae of Paragonimus heterotremus.

The newly excysted metacercariae of P. heterotremus were examined by scanning electron microscopy (SEM). Large dome-shaped papillae, small ones with a pit, and small ones with a smooth surface were observed around the suckers. The number of the small dome-shaped papillae with a pit was about 30 around the oral sucker and that of the small ones with a smooth surface varied from 9 to 13 around the ventral sucker. The present report is the first record of excysted metacercariae of P. heterotremus examined by SEM.