A Retrospective Clinicopathologic Study of Fibropapillomatosis in Rehabilitating Sea Turtles
Abstract
Fibropapillomatosis (FP), a neoplastic disease of sea turtles with a likely primary herpesviral etiology, is characterized by variable numbers of cutaneous, conjunctival, and occasionally visceral growths.5,6 Over the past three decades, FP has emerged as an important disease in green sea turtles (Chelonia mydas), and has reached epizootic proportions in several locations.3,4,8 We characterized and statistically evaluated the occurrence, clinical presentation, case progression, and outcome of sea turtles with FP at a rehabilitation facility, the Georgia Sea Turtle Center, Jekyll Island, GA (GSTC). As a control group, we also evaluated case data from an equivalent set of non-FP rehabilitating turtles. Tumor scores (0–3) were assigned to all patients according to size, number, and location.9 During 2009–2012, FP was present in ~ 5% (n = 18) of rehabilitating sea turtles at the GSTC, including green (Chelonia mydas) and Kemp's ridley (Lepidochelys kempii) turtles. The majority of the turtles with FP (FP+) were juvenile (94.4%),1 female (87.5%), green (94.4%) sea turtles. Most of these cases (61.1%) were found along the Florida coast; 38.7% were found in Georgia. Proportions of strandings of FP+ cases did not significantly differ by season (warm/cool) or month. Neither straight carapace length nor weight differed significantly between FP+ and control cases. Highest FP prevalence was in the 25–29.9 cm and 40–44.9 cm SCL size classes (22.2% each). Odds ratios analysis showed that two sources of co-morbidity, floating and emaciation, were significantly more likely to be observed in FP+ turtles than in non-FP turtles. Average time in rehabilitation was 251 days (± SE 18.94) for FP+ turtles, and 127 days (± SE 62.59) for non-FP turtles. Time to FP onset ranged in weeks from 0 (44.4%); to 1–10 (27.8%); to 11–20 (5.6%); to 31–40 (22.2%). Blood parameter abnormalities observed concurrent with peak FP severity include anemia (33.3%); monocytosis and eosinophilia (27.8% each); increased creatine kinase (38.9%); hyperphosphatemia (33.3%); hypoproteinemia (27.8%); hypocalcemia (22.2%); and hypoalbuminemia (16.7%).2 Discriminant function analysis of blood parameters suggests that turtles can be classified into groups (FP+ vs. non-FP) by blood parameters tested on the day of admission into the GSTC, but not during peak tumor severity.7 We related clinical pathology parameters to tumor scores, using means and standard errors of blood parameter values.9 Of the FP+ cases, the following outcomes were seen: 61.1% were released following rehabilitation (22.2% released with mild cutaneous FP; 38.9% released tumor-free); 22.2% were euthanized due to FP; 11.1% died in captivity; and 5.6% (i.e., one turtle) lives in permanent captivity. Odds ratio analysis of FP presence/absence and case outcome (released vs. euthanized) revealed that FP+ turtles had significantly greater odds of being euthanized than non-FP turtles. All euthanized FP+ turtles had a peak tumor score 3; all released FP+ turtles had a peak tumor score 1 or 2. These results provide a logical summary of the multifactorial aspects of FP cases in rehabilitation, suggest important parameters to evaluate in prospective FP cases, and provide potential predictors for possible case outcomes.
Acknowledgements
The authors wish to thank the University of Georgia, College of Veterinary Medicine, for financial and interdisciplinary support. Dr. Page-Karjian was supported by a Ph.D. Scholars of Excellence Graduate School Assistantship award. The authors thank the Georgia Sea Turtle Center staff for technical assistance.
* Presenting author
+ Student presenter
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