Severe spirorchiidiasis associated with fibropapillomatosis in a juvenile green turtle (Chelonia mydas) from Alagoas, Brazil

Abstract

Spirorchiid blood flukes and fibropapillomatosis are important health concerns of sea turtles, particularly juvenile green turtles (Chelonia mydas). This report describes their concurrent occurrence in a free-ranging juvenile stranded alive on the coast of Alagoas, northeastern Brazil. The turtle had a carapace length of 37 cm, poor body condition, severe pallor, dehydration, ocular abnormalities, apathy, multiple cutaneous masses, and a 12-cm deep carapacial fracture. It died approximately four hours after admission. Necropsy revealed hemorrhagic coelomic fluid, multifocal dark visceral lesions, cardiac dilation, and numerous leaf-shaped trematodes in the cardiac chambers and mesenteric vessels, of which approximately 15 were collected for parasitological examination. Morphological features were consistent with Learedius learedi, although molecular confirmation was not performed. Histopathology demonstrated widespread egg-associated granulomas in the heart, lungs, liver, spleen, kidneys, and intestines. Most eggs were compatible with spirorchiid type 1 morphology, whereas rare rounded, non-filamented eggs were suggestive, but not diagnostic, of Neospirorchis spp. Cutaneous and eyelid masses showed epithelial and fibroblastic proliferation consistent with fibropapillomas. Acute traumatic injury with internal hemorrhage was considered the most likely immediate cause of death, while systemic spirorchiidiasis, fibropapillomatosis, poor body condition, and chronic debilitation were considered significant pre-existing conditions. This case highlights the value of integrated necropsy, parasitology, and histopathology in sea turtle mortality investigations.