LIGHT AND SCANNING ELECTRON MICROSCOPIC OBSERVATIONS OF THE LARVAL STAGES AND ADULT OF SPHAERIDIOTREMA GLOBULUS (TREMATODA: PSILOSTOMIDAE)

Abstract

Sphaeridiotrema globulus (Rudolphi, 1814) is a digenetic trematode occurring in river and lentic aquatic systems in North America and has been identified as the cause of ulcerative hemorrhagic enteritis in waterfowl. The purpose of this study was to describe the stages of S. globulus using light (LM) and scanning electron microscopy (SEM). Elimia virginica snails infected with S. globulus were collected from Lake Musconetcong, NJ. Daughter rediae and cercariae were collected from the infected snails and LM and SEM microscopy were used to describe these stages with particular emphasis on the tegumentary surface. The tegument of S. globulus daughter rediae and cercariae is aspinose. The daughter rediae and cercariae showed simpler tegumentary structures than similar stages described in several species of echinostomids.