Bernard Fried

Echinostomes as experimental models for biological research.

Preface. 1. Biology of Echinostomes - An Overview I. Kanev, et al. 2. The Systematics of the Echinostomes A. Kostadinova, D.I. Gibson. 3. Echinostomes in Veterinary and Wildlife Parasitology J.E. Huffman. 4. Human Echinostomiasis: Mechanisms of Pathogenesis and Host Resistance M.A. Haseeb, L.K. Eveland. 5. Maintenance, Cultivation, and Excystation of Echinostomes B. Fried. 6. Ultrastructural Studies on Echinostomes T. Fujino, H. Ichikawa. 7. Reproductive Physiology and Behavior of Echinostoimes P.M. Nollen. 8. Immunobiology of the Relationship of Echinostomes with Snail Intermediate Hosts C.M. Adema, et al. 9. The Behavioral Biology of Echinostomes W. Haas. 10. Physiology and Biochemistry of Echinostomes J. Barrett. 11. Neuromusculature - Structure and Functional Correlates J.E. Humphries, et al. 12. Immunobiology and Immunodiagnosis of Echninostomiasis T.K. Graczyk. 13. Molecular Biology of Echinostomes J.A.T. Morgan, D. Blair.

An Overview of the Biology of Echinostomes

Echinostomes are digenean parasites in the class Trematoda. The adult worms are parasites of fishes, reptiles, birds and mammals, including humans. Their characteristic morphological feature is a crown of spines and a collar-like tegumentary flap surrounding the oral sucker. Larval stages develop in freshwater and marine snails, mussels, insects, amphibians and reptiles. Adult and larval echinostomes are used widely as models for laboratory work for the following reasons: n n1). n nThey are wide spred and common and some species are cosmopolitan. Other species are found in several geographical regions. Relatively few species are restricted locally. n n n n n2). n nThey are found in many wild and domestic birds and mammals, including humans. Many echinostomes are hematophagous, ingesting lymph and blood from their hosts. Therefore, they are parasites with significant health and economic importance. Some species such as Echinostoma lindoense Sandground & Bonne, 1940 (known after Kanev, 1985 as E. echinatum Zeder, 1803) and E. ilocanum (Garrison, 1908) cause severe health problems in humans in Southeast Asia. n n n n n3). n nEchinostomes infect most organs and sites in the abdominal cavity of birds and mammals, including the alimentary, excretory and reproductive systems. n n n n n4). n nLarval and adult echinostomes provide good material for biological, physiological, biochemical, immunological and other studies in modern biology. n n n n n5). n nEchinostomes can be maintained easily and inexpensively in the laboratory.

The biology of Echinoparyphium (Trematoda, Echinostomatidae)

Echinoparyphium species are common, widely distributed intestinal parasites causing disease in animals worldwide. Intermediate hosts include snails, bivalves, and fish, whereas the definitive hosts are mainly birds and mammals. This review examines the significant literature on Echinoparyphium. Descriptive studies, life cycle, experimental and manipulative studies, and biochemical and molecular studies are presented. The influence of environmental factors, and toxic pollutants, are reviewed as well as studies on the pathology of Echinoparyphium.

Maintenance, Cultivation, and Excystation of Echinostomes

The need for a consistent and reliable source of material is important for continued research on parasitic helminths. Often, only a particular stage in the life cycle of a helminth is available and workers have exploited use of that stage. For instance, Halton and colleagues (see Smyth and Halton, 1983 for review) have examined various aspects of the biology of the monogenean Diclidophora merlangi, by obtaining these parasites from the gills of naturally infected adult whitings, Merlanguis merlanguis. My laboratory has relied on obtaining Echinostoma trivolvis cercariae from naturally infected Helisoma trivolvis snails in a farm pond in Northampton County, PA for continuing studies on the biology of echinostomes (Schmidt and Fried, 1997).