HomePhilippine Journal of Veterinary Medicinevol. 44 no. 2 (2007)

Scanning Electron Microscope Observations on the Tegumental Surface of Adult Eurytrema pancreaticum (Janson, 1889) Looss, 1907 (Trematoda: Dicrocoeliidae), a Parasite of Ruminants in the Philippines

Salcedo L. Eduardo | Henry G. Sy

Discipline: Veterinary Medicine

 

Abstract:

The tegumental surface of adult Eurytrema pancreaticum from the pancreas of water buffaloes and cattle in the Philippines was studied under the scanning electron microscope (SEM). Specimens were processed following standard procedure of fixation, post-fixation, gradual dehydration, critically-point drying, and coating with gold for examining under the SEM. Adult Eurytrema pancreaticum appeared leaf-like, oval to pyriform in shape, thick at the midregion from anterior to posterior along the region of the oral and ventral suckers and less thick laterally forming a "fringe". Tegument is devoid of spines or scales. Ventral surface is marked with transverse ridges on the anterior region and with irregular folds on the posterior region. Dome-shaped papillae with smooth apical surface are found altered on the ventral surface but were concentrated around the oral and ventral suckers and in concentric rows around the genital pore opening. Irregular and anastomosing networks cover the cirrus surface giving a mesh-like appearance. The dorsal surface except althe mid-caudal portion is marked with irregularly arranged and transversely directed short ridges giving the surface a rough appearance. Dome-shaped papillae with smooth apical surface but with irregular borders were randomly scattered on the anterior fourth of the dorsal and lateral sides of the body. The mid-caudal portion revealed a small porous surface and few smaller dome-shaped papillae with apical cilia. The tegumental surface of Eurytrema pancreaticum is compared with those of other trematodes examined by SEM especially with respect to the occurrence and distribution of the tegumental papillae. The possible function especially of the tegumental papillae, the porous area on the dorsal side, the network of ridges on the cirrus and lateral "fringe" is discussed.