Literaturdatenbank
Literaturdatenbank |
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Johnson, A. J. (2006). Iridovirus infections of captive and free-ranging chelonians in the united states. Unpublished thesis PhD, University of Florida.
Added by: Sarina Wunderlich (28 Feb 2010 12:07:21 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Johnson2006a View all bibliographic details  |
Categories: General Keywords: Emydidae, Geochelone, Geochelone elegans, Geochelone platynota, Schildkröten = turtles + tortoises, Terrapene, Terrapene ornata, Testudinidae, Trachemys, Trachemys ornata, Trachemys scripta, Veterinärmedizin = veterinary medicine, Viren = viruses Creators: Johnson Publisher: University of Florida |
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Testudinidae Iridoviruses of the genus Ranavirus are well known for causing mass mortality events of fish and amphibians with sporadic reports of infection in reptiles. The objective of this study was to characterize Ranavirus infections of chelonians. First, histopathologic and molecular investigations of naturally occurring infections in several species of chelonian were investigated. A virus isolate (BSTRV) obtained from a captive Burmese star tortoise (Geochelone platynota ) was experimentally inoculated into western ornate box turtles (Terrapene ornata ornata ) and red-eared sliders (Trachemys scripta elegans ). Oral transmission failed to create illness, however five of six turtles inoculated intramuscularly developed clinical and histologic lesions consistent with naturally infected cases. Virus was re-isolated, fulfilling Koch's postulates and establishing BSTRV as a causative agent of disease and mortality in chelonians. Restriction enzyme analysis of this isolate with an isolate from a leopard frog ( Rana utricularia ) obtained at the site where the tortoise died was found to have identical restriction patterns suggesting xii they are either the same or very closely related strains. This indicates that amphibians might serve as a source of infection for chelonians, or vice versa. BSTRV was also utilized as a coating antigen in the development of an indirect enzyme linked immunosorbent assay (ELISA). Plasma from a surviving pen-mate of the Burmese star tortoise served as a positive control for optimization. A seroprevalence study of 1000 banked free-ranging gopher tortoise plasma samples found that only 1.5% of tortoises were positive for exposure to the virus. The role of amphibians in the route of transmission of virus was assessed by experimentally inoculating leopard frogs, euthanizing them, homogenizing them, and feeding them to turtles via feeding tubes over a six-week period. All turtles failed to develop clinical signs or to produce anti-Ranavirus antibodies over three months. Lastly, the antiviral compound acyclovir was assessed at 0, 0.2, 1, 5, 10, and 25/ml for its ability to reduce or eliminate virus replication in vitro and to create cytotoxicity in Terrapene heart cells. No cytotoxicity was observed at any concentration. Increasing concentration found only a slight ten fold reduction in virus titer from 104.8 to 103.8 TCID50 .
Added by: Sarina Wunderlich |