Replication and persistence of VHSV IVb in freshwater turtles

Abstract

With the emergence of viral hemorrhagic septicemia virus (VHSV) strain IVb in the Great Lakes of North America, hatchery managers have become concerned that this important pathogen could be transmitted by animals other than fish. Turtles are likely candidates because they are poikilotherms that feed on dead fish, but there are very few reports of rhabdovirus infections in reptiles and no reports of the fish rhabdoviruses in animals other than teleosts. We injected common snapping turtles Chelydra serpentine and red-eared sliders Trachemys scripta elegans intraperitoneally with 10(4) median tissue culture infectious dose (TCID50) of VHSV-IVb and 21 d later were able to detect the virus by quantitative real-time reverse transcriptase PCR (qrt-RTPCR) in pools of kidney, liver, and spleen. In a second experiment, snapping turtles, red-eared sliders, yellow-bellied sliders T. scripta scripta, and northern map turtles Grapetemys geographica at 14 degrees C were allowed to feed on tissues from bluegill dying of VHSV IVb disease. Turtle kidney, spleen, and brain pools were not positive by qrt-RTPCR on Day 3 post feeding, but were positive on Days 10 and 20. Map turtles on Day 20 post-feeding were positive by both qrt-RTPCR and by cell culture. Our work shows that turtles that consume infected fish are a possible vector for VHSV IVb, and that the fish rhabdoviruses may have a broader host range than previously suspected.