<u>Diplostomulum trituri</u> is associated with pathological damage which includes increased size of the ventricles and loss of neural tissue. Neurophysiological symptoms of parasitism include sluggish behavior and poor reflexes. Black material was observed in the lumen of the intestinal ceca. Several mesocercariae were observed to be attached to the neural tissue by their oral sucker. In 150 newts examined from Mountain Lake, Giles County, Virginia, the incidence of infection with <u>D. trituri</u> was 100 percent. The total number of parasites in the brain and surrounding area ranged from 2 to 300. The number of mesocercariae in the ventricles of the brain was approximated to range from 5 to 30. The attempts to recover the encysted larval stage and/or adult failed using Japanese quail, mallard ducks, raccoon, muskrat, opossum, domestic cat, and fish from families Salmonidae, Catostomidae, Cyprinidae, and Centrarchidae as experimental definitive hosts for <u>Diplostomulum trituri</u>. / Master of Science