Green Turtle Fibropapillomatosis: Tumor Morphology and Growth Rate in a Rehabilitation Setting

Abstract

Fibropapillomatosis (FP) is a neoplastic disease most often found in green turtles (Chelonia mydas). Afflicted turtles are burdened with potentially debilitating tumors concentrated externally on the soft tissues, plastron, and eyes and internally on the lungs, kidneys, and the heart. Clinical signs occur at various levels, ranging from mild disease to severe debilitation. Tumors can both progress and regress in affected turtles, with outcomes ranging from death due to the disease to complete regression. Since its official description in the scientific literature in 1938, tumor growth rates have been rarely documented. In addition, FP tumors come in two very different morphologies; yet, to our knowledge, there have been no quantified differences in growth rates between tumor types. FP tumors are often rugose in texture, with a polypoid to papillomatous morphology, and may or may not be pedunculated. In other cases, tumors are smooth, with a skin-like surface texture and little to no papillose structures. In our study, we assessed growth-rate differences between rugose and smooth tumor morphologies in a rehabilitation setting. We measured average biweekly tumor growth over time in green turtles undergoing rehabilitation at the University of Florida Whitney Laboratory Sea Turtle Hospital in St. Augustine, Florida, and compared growth between rugose and smooth tumors. Our results demonstrate that both rugose and smooth tumors follow a similar active growth progression pattern, but rugose tumors grew at significantly faster rates (p = 0.013) than smooth ones. We also documented regression across several examined tumors, ranging from −0.19% up to −10.8% average biweekly negative growth. Our study offers a first-ever assessment of differential growth between tumor morphologies and an additional diagnostic feature that may lead to a more comprehensive understanding and treatment of the disease. We support the importance of tumor morphological categorization (rugose versus smooth) being documented in future FP hospital- and field-based health assessments.

Assessing the Relationship between Sea Turtle Strandings and Anthropogenic Impacts in Taiwan

“…As a consequence of the aforementioned circumstances, the current study focused on threats from environmental contaminants, a priority area of research for marine sea turtle conservation [4,57]. Fibropapillomatosis (FP), for example, is a tumor-forming disease that affects all species of sea turtles and is most commonly found in green turtles [5,6,11,12]. A higher prevalence of FP in sea turtles has been documented in highly contaminated marine environments or environments with poor water quality [48,49,58,59].…”

“…However, as green turtles face numerous threats that are unrelated to wind farms (e.g., human activity, including fishery bycatch, illegal egg poaching, coastal development, marine debris, global environmental change, marine pollution, and anthropogenic-exacerbated disease including fibropapillomatosis (FP), etc.) [2][3][4][5][6][7][8][9][10][11][12], it can be difficult to distinguish between the effects of these threats and the impact of wind farms on the marine turtles.…”