EXPERIMENTAL CHALLENGE STUDY OF FV3-LIKE RANAVIRUS INFECTION IN PREVIOUSLY FV3-LIKE RANAVIRUS INFECTED EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) TO ASSESS INFECTION AND SURVIVAL.

The Maryland Zoo in Baltimore experienced an outbreak of Frog virus-3 (FV3)-like ranavirus during the summer of 2011, during which 14 of 27 (52%) of its captive eastern box turtles (Terrapene carolina carolina) survived. To assess survival, immunity, and viral shedding, an experimental challenge study was performed in which the surviving, previously infected turtles were reinfected with the outbreak strain of FV3-like ranavirus. Seven turtles were inoculated with virus intramuscularly and four control turtles received saline intramuscularly. The turtles were monitored for 8 wk with blood and oral swabs collected for quantitative polymerase chain reaction (qPCR). During that time, one of seven (14%) inoculated turtles and none of the controls (0%) died; there was no significant difference in survival. Clinical signs of the inoculated turtles, except for the turtle that died, were mild compared to the original outbreak. Quantitative PCR for FV3-like ranavirus on blood and oral swabs was positive for all inoculated turtles and negative for all controls. The turtle that died had intracytoplasmic inclusion bodies in multiple organs. Three inoculated and two control turtles were euthanized at the end of the study. No inclusion bodies were present in any of the organs. Quantitative PCR detected FV3-like ranavirus in the spleen of a control turtle, which suggested persistence of the virus. The surviving five turtles were qPCR-negative for FV3-like ranavirus from blood and oral swabs after brumation. Quantitative PCR for Terrapene herpesvirus 1 found no association between ranavirus infection and herpesvirus loads. In conclusion, previously infected eastern box turtles can be reinfected with the same strain of FV3-like ranavirus and show mild to no clinical signs but can shed the virus from the oral cavity.

KUDOA SP. (Myxozoa: Multivalvulida) in skeletal muscle of captive bullnose eagle rays, Myliobatis freminvillei (Rajiformes: Myliobatidae).

Kudoa spp. (Myxozoa: Multivalvulida) are of significant concern in marine and estuarine teleosts because of trophozoites and spores in the skeletal muscle reducing the marketability of wild and cultured fish. Kudoa spp. have rarely been reported from elasmobranchs. Spores of a Kudoa sp. were identified in two captive, mature bullnose eagle rays (Myliobatisfreminvillei) (Rajiformes: Myliobatidae). The male bullnose eagle ray (case 1) showed intractable weight loss, muscle wasting, and hyperkalemia, and was euthanized. The skeletal muscle showed myofiber degeneration, vacuolation, and necrosis, and spores of a Kudoa sp. were present multifocally through the muscle. The female bullnose eagle ray (case 2) had a severe, rapidly progressive, erosive lesion extending through the pectoral fin and was euthanized. Spores of a Kudoa sp. were not found in the lesion but were present in two disparate sections of skeletal muscle. There was no inflammation or degeneration associated with the infected myofibers in case 2. From case 1, morphometrics of 15 spores in histologic section were apical width 6.5-8.0 µm, apical thickness 5.0-7.0 µm, lateral width 5.5-6.5 µm, length 4.5-6.5 µm; the equal-sized polar capsules were spherical, 1.5-2.5 µm in diameter; there was a clear halo 2 µm thick around the spores, considered to be a mucous envelope. Spores from case 2 were indistinguishable from those in case 1. This appears to be the first report of Kudoa sp. in bullnose eagle rays.