Ranavirus

This woodland photo was taken of one of our large males at the end of August, 2003. He was full of vigor and on his return trek from a long (>400 yard) 3-day excursion that took him from his usual habitat into a region where turtles had recently died from an outbreak of Ranavirus. 


Three weeks after the photo was taken, this male displayed severe signs of the viral infection and was evacuated for therapy in our infirmary (where he died 50 hours later).  We wonderred whether he contracted the disease during his sojourn in habitat where the virus was known to be active.  Such an obvious inference, however, is not reliable. Despite the circumstances surrounding this male's disease, we have other evidence that suggests that the virus may not be transmitted by turtle-to-turtle proximity, or even by contact. Significant insights gained from investigation by the University of Florida Veterinary College laboratories in Gainesville still leave many unknowns about the mechanism by which this virus gets transmitted to turtles.

This second image shows a moribund turtle displaying the severe disease signs seen in turtles infected with this virus, not many days before death. He died only 10 hours after this photo was taken.  



The Ranavirus infection is quickly fatal. The virus damages numerous organs so quickly that an infected turtle can appear to be in good health one day, but appear with near-terminal signs a week or less later, and be dead within hours or days after that.
Our observations and immunology findings provided by the U of Fla Veterinary College lead us to suspect that the virus kills too quickly for infected individuals to have sufficient time to mount an effective immune response.

For interested readers, our general overview of the viral outbreak and progression in wild habitat was published in an article that is now available on-line at http://herpetology.com/belzer/boxturtle.htm

More details from our experience with this disease will be published shortly. We have authored a paper ( A natural history of Ranavirus in an eastern box turtle population) which details the 4-year progression, and eventual subsidence, of the disease in a wild population. The paper is projected for publication in Turtle and Tortoise Newsletter in late 2009 or early 2010.  The text shares an extensive array of observations we made in the field before, during and after the outbreak, and of the pathology data provided us by numerous cooperating laboratories, so that other fieldworkers will have a baseline of insight into this poorly understood and very lethal disease.  The virus (historically recognized as a pathogen affecting amphibians and fish) is now known to have caused sudden deaths in wild populations of various and disparate turtle species.