Abstract
Fibropapillomatosis (FP) is a disease associated with herpesvirus ChHV5,1 primarily impacting green turtles (Chelonia mydas) in tropical environments2. Symptoms of the disease include gross tumors, debilitation, and lethargy.1 Juvenile to sub-adult green turtles populating inshore areas show the highest disease prevalence, defined by the presence of gross tumors in turtles presenting at rehabilitation centers.3 Global disease prevalence varies from 0% to 92%.4 In Florida, disease prevalence is higher on the Gulf of Mexico (GoM), at 51.9%, compared to the Atlantic Coast 11.9%.2 Despite this, most FP studies in Florida have focused on the East Coast and the Keys.5-9
For this study, sea turtle stranding data from 2000–2020 from West Florida were reviewed. Pinellas and Collier counties were the northern and southernmost boundaries, respectively. The objective was to identify any potential associations to causes and impacts of disease expression and comorbidities associated with FP. This study reviewed instances of human interactions, body condition, gastrointestinal contents, pathologies, and other internal symptoms as defined by the standardized sea turtle necropsy form provided by the Sea Turtle Stranding Network (STSSN). Comparisons were made between a group of FP-diseased turtles and a control group without evidence of FP. Descriptive observations were categorized into a semi-quantitative score for each data category and a gastrointestinal contents score (GCS), which encapsulates the quantity of gastrointestinal contents and duration since their last meal.
The external examination results support those reported in a similar study using data from 1980–1998. This includes a higher likelihood of emaciation and entanglement in FP-diseased turtles, lower likelihood of vessel-strike-related injuries, and higher chance of turtles with evidence of FP stranding in winter months.2 Internal examination data, however, is lacking in previous studies. Applying odds ratios to necropsy data revealed that FP turtles are 3.97 times more likely to have hard feces, 1.85 times more likely to have depleted livers, 2.2 times more likely to overproduce bile, 3.85 times more likely to have fluid in their respiratory system, and 1.98 times more likely to host parasites. Marine leeches, identified as a potential disease vector,10 were only found on turtles with gross tumors. FP-diseased turtles had a lower average GCS than the control group and more frequently had distended gallbladders, whereas the control group more frequently had empty gallbladders. Obstructed vision due to gross tumors was also found to increase an individual’s likelihood of pathologies related to nutritional health.
The results of this study may inform sea turtle rehabilitators in their treatment of patients with FP. Furthermore, our review of stranding data sheds light on inconsistencies of FP documentation in the STSSN and may help guide necropsy examiners by suggesting more clear-cut documentation of nutritional health than currently exists on the necropsy form.
Acknowledgements
The authors would like to thank Mote Marine Laboratory’s Stranding Investigations Program, the Sea Turtle Stranding Network, and Florida Fish and Wildlife Commission for the contribution of their data to this study, as well as their ongoing efforts in sea turtle conservation and management. We also wish to thank Jess Blackburn and Amber Lea Kincaid for the generosity of their time, guidance, and intellectual contributions throughout the construction of this project. This study, and all rescue, rehabilitation, and necropsy efforts encompassed in the data, were conducted under FWC MTP #126.
*Presenting author
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