Management of a Concurrent Ranavirus and Herpesvirus Epizootic Event in Captive Eastern Box Turtles (Terrapene Carolina carolina)
1Hospital Department, Maryland Zoo in Baltimore, MD, USA; 2Department of Comparative Biosciences, University of Illinois Urbana-Champaign, Urbana, IL, USA; 3Animal Department, Maryland Zoo in Baltimore, Baltimore, MD, USA
Ranavirus is an emerging pathogen affecting captive and wild Eastern Box Turtles (Terrapene carolina carolina) in eastern North America. In July 2011, five Eastern Box Turtles from a group of 27 presented dead or moribund with fibrinonecrotic stomatitis and cloacitis. The remaining 22 animals were quarantined indoors and isolated into one of three groups based on clinical severity: no lesions, mild, or severe. Treatment included nutritional support, fluid therapy, antibiotics, and antiviral famciclovir (10, 20, or 30 mg/kg p.o. q 24 hr, randomly assigned). Treatment was discontinued at 34 days for the no lesions group and 10 days after clinical resolution for the others. Oral swabs from days 0, 10, 34, and 60 were tested for Ranavirus by quantitative real-time PCR and from day 0 for Herpesvirus by conventional PCR. On day 80, the surviving 14 turtles were returned to the outdoor exhibit for brumation. Overall, 77.3% tested positive for Ranavirus and 54.5% for Herpesvirus. Median duration of treatment for Ranavirus-positive survivors was 49 days (range 34–80 days). On days 0, 10, 34, and 60, Ranavirus prevalence was 72.7% (n=22; median viral copies (MVC) 7.06x106), 50% (n=18; MVC 9.11x107), 31.3% (n=16; MVC 2.46x106), and 0% (n=14; MVC 0). The survival rate was 64.7% (n=11) among those that were Ranavirus-positive. Of the 17 Ranavirus-positive animals, 10 were concurrently Herpesvirus-positive. Survival was 57% among those that tested only Ranavirus-positive, and 70% among those that tested positive for Ranavirus and Herpesvirus. All 14 turtles survived brumation, showing no clinical signs 1 mo after emergence.