Abstract

Ranavirus has caused mass mortality events in wildlife populations of reptiles and amphibians worldwide, and is proposed as a significant threat to biodiversity. The pathogenicity of Ranavirus has been documented to vary in adult chelonian species at different environmental temperatures, but has yet to be determined in juveniles. The objective of this study was to determine the pathogenicity of Ranavirus in four species of juvenile chelonians: red-eared sliders (RES), Mississippi map turtles (MMT), false map turtles (FMT), and river cooters (RC) at two environmental temperatures. Two simultaneous trials (n = 8 treatment and n = 4 controls of each species) were conducted in separate temperature-controlled rooms with animals maintained at 22°C or 27°C. Each treatment individual was infected via intramuscular injection with 5 x 10⁵ TCID50 of a FV3-like virus isolated from a box turtle, while each control animal was injected with a similar volume of cell lysate. There was 100% mortality observed in each species at each temperature. Median survival time (MST) varied between 6 and 12 days, with RES in the 27°C trial surviving the shortest and the FMT in the 22°C trial surviving the longest. When combining all species, turtles in the 27°C trial survived fewer days than those housed at 22°C, despite all turtles in the 22°C trial having higher viral copies detected in post-mortem tissues. This study confirmed that juvenile chelonians have a high susceptibility to ranaviral disease.

Acknowledgements

Funding for this project was provided by the Merial Veterinary Scholars Program and the Wildlife Epidemiology Lab at the University of Illinois.

* Presenting author