Abstract

Fibropapillomatosis (FP) is an infectious, neoplastic disease that affects all hard-shelled sea turtle species, and has been reported in all oceans. FP tumors are characterized by cutaneous, ocular, and visceral growths, and often debilitate affected animals by inhibiting feeding and movement, obscuring vision, and/or leading to organ failure.^1,2 In sea turtle rehabilitation facilities, FP is a major concern because it necessitates strict quarantine protocols and can extend rehabilitation time and complicate prognoses.³ In this study, we evaluated FP occurrence, tumor score, tumor removal, and tumor regrowth in rehabilitating sea turtles using descriptive statistics, and developed prognostic recommendations based on these factors. We analyzed medical records of sea turtle patients with FP in four rehabilitation facilities in the southeastern United States during 2009–2017, including 758 green (Chelonia mydas), 5 loggerhead (Caretta caretta), 5 Kemp’s ridley (Lepidochelys kempii), and 1 hawksbill (Eretmochelys imbricata) turtles. Of 769 cases, 218 underwent tumor removal surgery, and 72% of those had tumor regrowth within an average of 50 (±54; range=2–373) days. For turtles that had surgical tumor removal, number of regrowth episodes per turtle ranged from 0–12, with the majority (78%) experiencing 0, 1, or 2 regrowth events during rehabilitative care. Occurrence of regrowth episodes was higher during May (12.6%) and June (13.2%) than during the other months (mean±std. dev.=7.42%±0.84%). Of the 769 turtles with FP, 200 (26%) lived to be released (n=193) or placed in a permanent facility (n=7), while 569 (74%) died (n=283) or were euthanized (n=286). Tumor regrowth following surgery was not significantly associated with case outcome using chi-square statistics with α=0.05. Additionally, two published FP tumor scoring systems were applied to all cases and compared in terms of case outcome using odds ratios.^3,4 While the two scoring systems did not significantly differ in survival odds for turtles assigned tumor scores 1 or 3, the survival odds for turtles assigned tumor score 2 using one scoring system were 2.2 times higher (95% CI, 1.31–3.84) than the survival odds for those assigned tumor score 2 using the other scoring system.^3,4 Across both scoring systems, an average of 60.8% (±0.28%), 32.3% (±12.24%), and 12.4% (±2.4%) of turtles with tumor scores 1, 2, and 3, respectively, survived rehabilitation. These data suggest that: (1) limited resources may be best invested in turtles without FP or with tumor score 1; (2) that FP tumor regrowth may be expected in about 72% of cases involving surgical removal; and (3) that tumor regrowth is more likely to occur during seasonal transitions into warmer temperatures. The results of this study may be used by caretakers and veterinarians to help guide clinical decision-making and determine prognoses for rehabilitating sea turtles with FP.

Acknowledgements

The authors thank The Turtle Hospital, Brevard Zoo Sea Turtle Healing Center, Clearwater Marine Aquarium, and the Georgia Sea Turtle Center for providing access to case records. Special thanks to Wendy Marks, Shelly Marquardt, Rachel Sommer, and Michelle Kaylor for assistance with case data organization. Justin Perrault assisted with data analysis and constructive feedback. This project was funded in part by a grant awarded from the Sea Turtle Grants Program. The Sea Turtle Grants Program is funded from proceeds from the sale of the Florida Sea Turtle License Plate. Learn more at www.helpingseaturtles.org/.

*Presenting author

Literature Cited

1.  Balazs GH. 1986. Fibropapillomas in Hawaiian green turtles. Mar Turtle Newsl. 39:1–3.

2.  Jacobson et al. 1989. Cutaneous fibropapillomas of green turtles (Chelonia mydas). J Comp Pathol. 101:39–52.

3.  Page-Karjian A, Norton TM, Krimer P, Groner M, Nelson SE Jr., Gottdenker NL. 2014. Factors influencing survivorship in rehabilitating green sea turtles (Chelonia mydas) with fibropapillomatosis. J Zoo Wildl Med. 45:507–519.

4.  Work TM, Balazs GH. 1999. Relating tumor score to hematology in green turtles with fibropapillomatosis in Hawaii. J Wildl Dis. 35:804–807.