Fibropapillomatosis (FP) is a neoplastic disease that affects marine turtles worldwide, especially green sea turtles (Chelonia mydas). FP tumors can develop on the body surface of marine turtles and also internally in the oral cavity and viscera. Depending on their quantity, size and anatomical distribution, these tumors can interfere with hydrodynamics and the ability to feed, hence scoring systems have been proposed in an attempt to quantify the clinical manifestation of FP. In order to establish a new scoring system adapted to geographic regions, we examined 214 juvenile green sea turtles with FP caught or rescued at Brazilian feeding areas, counted their 7466 tumors and classified them in relation to their size and anatomical distribution. The patterns in quantity, size and distribution of tumors revealed interesting aspects in the clinical manifestation of FP in specimens studied in Brazil, and that FP scoring systems developed for other areas might not perform adequately when applied to sea turtles on the Southwest Atlantic Ocean. We therefore propose a novel method to evaluate the clinical manifestation of FP: fibropapillomatosis index (FPI) that provides the Southwest Atlantic fibropapillomatosis score (FPS_SWA). In combination, these indexing and scoring systems allow for a more objective, rapid and detailed evaluation of the severity of FP in green sea turtles. While primarily designed for the clinical manifestation of FP currently witnessed in our dataset, this index and the score system can be adapted for other areas and compare the characteristics of the disease across regions. In conclusion, scoring systems to classify the severity of FP can assist our understanding on the environmental factors that modulate its development and its impacts on the individual and population health of green sea turtles.

Fibropapillomatosis (FP) can be an important conservation threat to green sea turtles (Chelonia mydas) due to its widespread distribution and complex aetiology. Thus, understanding the impacts of FP in sea turtle populations is a research priority towards conservation efforts. The body condition index (BCI), based on straight carapace length (SCL) and body mass (BM), is an accurate indicator of body-nutritional condition that can be used in routine green turtle health evaluations. This study aimed to compare BCI in FP-free (N = 369) and FP-affected (N = 518) green turtles from Brazilian feeding areas. Body condition indices were evaluated in terms of the South-west Atlantic Fibropapillomatosis Score – FPS_SWA(mild, moderate and severe), study sites (five Brazilian states), origin (intentional capture, fishery, stranding and afloat) and sex (when known). Curved and straight carapace lengths, and body mass were recorded in order to calculate BCI. Statistical analysis revealed significant differences in BCI among green turtles from different study areas (P= 0.02), and lower BCI values in FP-free than in FP-positive individuals (P< 0.0001). With regards to origin, the highest BCI was found in the intentional capture group (N = 245; 1.47 ± 0.16), followed by fishery (N = 180; 1.46 ± 0.20). Analysis according to sex revealed a higher mean BCI among females than males (P< 0.017). This study provides relevant data on the health and nutritional status of green turtles along the Brazilian coast, in important feeding areas for this species.

Many factors threaten the survival of marine turtles, such as incidental capture by fisheries, habitat degradation, pollution and diseases. One of the most important diseases is fibropapillomatosis (FP), characterized by the development of benign skin tumours. FP predominantly affects juvenile green sea turtles (Chelonia mydas) and involves a complex multifactorial aetiology. For several years, it has been noted that the prevalence of FP tends to be higher in marine environments under the influence of human activities, leading to the hypothesis that environmental pollutants play a role in the epidemiology of this disease. Organochlorine compounds (OCs) are persistent organic pollutants with immunosuppressive and carcinogenic effects in humans and wildlife. OC levels (α-BHC, β-BHC, α-endosulphan, β-endosulphan, endosulphan sulphate, pp′-DDD, op′-DDD, pp′-DDE, op′-DDE, heptachlor, dicofol and mirex) were quantified through gas chromatography with a micro-electron capture detector (GC-μECD) in liver and fat samples from 64 juvenile green sea turtles. Specimens with and without FP were analysed, after being caught at three feeding areas off the Brazilian coast: Ubatuba, Praia Grande and Vitória. OC levels were comparable to those observed in similar studies, and no consistent difference was observed between sea turtles with and without FP. This study helps to elucidate the contamination profile in sea turtles caught at feeding areas off Brazil and confirms that green sea turtles are exposed to OCs, which may play a negative role in the health of this species.