Showing papers on "Trematoda published in 1970"

Life Cycle of Procyotrema marsupiformis Harkema and Miller, 1959 (Trematoda: Strigeoidea: Diplostomatidae)

Abstract: The life cycle of P. marsupiformis, a pancreatic duct parasite of the raccoon, Procyon lotor, is described. Eggs were obtained from naturally and experimentally infected raccoons. Miracidia are of characteristic strigeoid morphology with 6 to 8 germinal cells. Mother and daughter sporocysts develop in the small planorbid snail, Promenetus exacuous (Say). Pharyngeate, longifurcate, distomate cercariae are liberated 3 weeks postinfection. The cercaria has 4 preacetabular glands and 20 flame cells. Cercariae penetrated tadpoles, but not adults, of Rana clamitans and R. pipiens sphenocephala. Adult frogs containing mesocercariae are infective to raccoons. Diplostomula develop within the tissue of the pancreas and then enter the pancreatic duct as young adults. Eggs are present in feces 18 days after feeding infected frogs to the definitive host. The strigeoid trematode, Procyotrema marsupiformis, has been reported from the pancreatic duct of the raccoon from Piedmont and coastal regions of North Carolina (Harkema and Miller, 1959) and Maryland (Locke and Brown, 1965), and from the gall bladders of three mink and one gray fox in North Carolina (Miller and Harkema, 1964). Locke and Brown commented on hyperplasia of the pancreatic duct caused by this parasite. Preliminary studies showed the intermediate hosts to be a small planorbid snail, Promenetus exacuous (Say) and adult frogs. The essential features of the life cycle are presented. MATERIALS AND METHODS Raccoons from salt-marsh habitats were used as experimental hosts after fecal examinations over a period of several weeks revealed no P. marsupiformis eggs. Autopsy records of raccoons from salt marshes had been negative for this trematode. The pancreatic ducts of infected raccoons were flushed with unfiltered swamp water from the habitat of naturally infected intermediate hosts, and eggs obtained in this manner were incubated in 3-inch finger bowls placed in the dark at approximately 25 C for 3 weeks without disturbing or changing the water. Hatching was effected by chilling embryonated eggs at 4 C and then placing them in direct sunlight. Living miracidia, either unstained or stained with neutral red and/or Nile blue sulfate, were mounted in fresh egg white or Received for publication 5 September 1969. * Paper No. 3034 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, N. C. t Supported in part by NIH Grant AI-05927 and NIH Postdoctoral Research Fellowship Award 1-F2-A1-32, 189-01. t Present address: Francis T. Nicholls State College, Thibodaux, Louisiana. methyl cellulose for study with light and phase microscopy. Miracidia prepared by the silver staining technique of Lynch (1933) and mounted in CMC-10 were used for measurements as well as determination of the epidermal plate pattern. Some were fixed in hot AFA, stained with Semichon's carmine, and mounted in Permount. Laboratory-reared snails were obtained by maintaining Promenetus exacuous in swamp water (pH 5.2 to 5.8) from endemic areas; food was decaying leaves of the water tupelo (Nyssa aquatica), the dominant plant species in those areas. Pond water, aerated tap water, and distilled water were unsatisfactory. The shell of P. exacuous is sufficiently transparent to permit study of living sporocysts within the snail. Mother and daughter sporocysts were removed and studied alive, or as fixed, stained, and mounted specimens. Living cercariae were studied as for miracidia whereas specimens prepared after the method of Talbot (1936) were measured. Laboratory-reared Rana clamitans tadpoles were used to study cercarial penetration and mesocercarial development. Tadpoles that had been exposed to 25 to 100 cercariae and naturally infected adult frogs were fed to uninfected