Seven species of sea turtles are Currently documented: the green turtle (Chelonia mydas), loggerhead turtle (Caretta caretta), leatherback turtle (Dermochelys coriacea), hawksbill turtle (Eretmochelys imbricata), olive ridley turtle (Lepidochelys olivacea), Kemp’s ridley turtle (Lepidochelys kempii), and flatback turtle (Natator depressus). Of these, only the first five occur along the Brazilian coast. All of them are included on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species (Kersting et al., 2009), highlighting the importance of understanding and studying the threats to their survival for their conservation.
These animals are susceptible to various pathologies, which may or may not be linked to anthropogenic actions. A recurring example along the Brazilian coast is fibropapillomatosis, a disease characterized by benign cutaneous tumors of varying sizes that appear on different parts of the turtles’ bodies, increasing their susceptibility to stranding. Although benign, these tumors can affect the turtles' swimming, vision, feeding, and breathing (Baptistotte, 2007). The number and size of nodules vary among individuals, commonly found on flippers, neck, periocular region, nostrils, tail base, and cloaca. Visceral nodules may also occur, typically in the lungs, kidneys, heart, gastrointestinal tract, and liver. In such cases, the tumors can impair organ function, causing, for example, intestinal obstruction or buoyancy issues (Rosa et al., 2021).
The disease has been reported in all oceans, and although the most affected species is
Chelonia mydas, it has also been observed in Caretta caretta, Lepidochelys olivacea, Lepidochelys kempii, and Dermochelys coriacea (Baptistotte, 2007). In Brazil, the first record
of the disease occurred in 1986 in Espírito Santo. Since then, new cases have been increasingly observed in turtle feeding areas. Turtles inhabiting coastal areas with high human population density and greater anthropogenic activity show a higher prevalence of fibropapillomatosis compared to turtles living in deeper waters, indicating that marine pollution may be a significant contributing factor (Ene, 2005).
The occurrence of this disease is associated with highly polluted areas and may also be
linked to other factors, such as chemical contaminants, ultraviolet radiation, parasites, and
bacterial infections (Gagliardi et al., 2018). These variables can weaken the immune system,
making the turtles more susceptible to the disease. The consequences of anthropogenic
actions in marine habitats extend beyond fibropapillomatosis, potentially affecting sea turtle
physiology, causing chronic stress, and impairing immune function (Gagliardi et al., 2018).
As marine animals that surface to breathe, sea turtles are exposed to both marine and atmospheric pollution, making them excellent sentinels of environmental health (Baptistotte,
2007).
To date, the etiological agent of fibropapillomatosis remains unknown, though it is believed to be caused by a herpesvirus named “Chelonid Fibropapilloma Associated Herpesvirus” (C-FP-HV), which has been isolated in 100% of naturally occurring tumors (Ene et al., 2005). It is common for affected individuals to be infested with ectoparasites, which may serve as potential vectors for the herpesvirus causing fibropapillomatosis (Santos et al., 2008).
Diagnosis is clinically performed by observing the papillomas and can be confirmed through histological examination. Currently, there is no preventive therapy for fibropapillomatosis, with the primary treatment being the surgical removal of tumors, although recurrence is possible (Rosa, 2021).
The increasing impact of human activities on marine ecosystems is inevitable, and fibropapillomatosis in sea turtles is just one of many consequences of this imbalance. The rise in pollution and climate change affects not only turtles but also various marine species, compromising the ecological balance that sustains the oceans. In Brazil, institutions such as the Chico Mendes Institute for Biodiversity Conservation (ICMBio) and various universities actively monitor the occurrence of this disease and promote awareness of the importance of sea turtle conservation. However, it is essential for the general public to engage in preservation actions, such as reducing plastic use. As bioindicators of marine ecosystems, turtles highlight the urgency of reevaluating environmental practices and adopting more sustainable strategies to ensure the conservation of these and other species.
Autor: Roberta Stopasolla Pinto
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