Determinação da causa de morte e principais achados patológicos em tartarugas-verdes, Chelonia mydas no litoral norte da Bahia

Abstract

The objective of this study was to evaluate the pathological findings in green turtles (Chelonia mydas) and their impact on conservation, correlating them with fishing, parasitic infections by spirorchids, as well as the identification of ocular pathologies. Sixty-one animals (46 females and 15 males) were necropsied and samples of organs with lesions identified by macroscopy were collected for histopathological evaluation. Data from animals confirmed or suggestive of interaction with fishing were recorded. Of the total number of turtles evaluated, it was possible to determine the cause of death in 90,2% of the turtles, 77% of which were natural threats, 16.7% of the cases were associated with human interaction and 6.6% were inconclusive. Regarding cause of death, 44.3% died of acute respiratory failure; 26.2% of sepsis, 16.4% due to cachexia/malnutrition, 4.9% had circulatory collapse due to thromboembolism and 1.6% had gastric compaction. In inconclusive cases, 3.3% were not observed macroscopic changes determining death. 3.3% of the animals were found to be euthanized. To identify the occurrence of trematodes of the family Spirorchiidae and the lesions caused by these parasites, fecal samples were collected from 41/61 (68.3%) necropsied animals, and of these, 6.5% had adult parasites, which were located in the light of large vases. The coproparasitological evaluation allowed the identification of three types of spirorchid eggs, using the sedimentation technique. The lesions caused by these parasites were granulomas in the TGI serosa (24.6%), parasitic splenitis (19.4%) and thrombus formation in the arteries, with consequent partial or total obstruction (14.7%) of its lumen. The affected arteries were left and right aortas, brachiocephalic trunk, dorsal aorta and celiac and cranial mesenteric arteries. Parasitic granulomas in vessel walls were also observed; in 8.2% of the vessels there were thrombi and granulomatous formation in the wall. Another change observed in the vessels was the proliferation of fibrous tissue or endarteritis (9.3%). The most common microscopic findings were pneumonia with parasitic granulomatous vasculitis (54.1%), splenitis and parasitic granulomatous vasculitis (37.7%), nephritis and granulomatous vasculitis (34.4%), heterophilic granulomatous hepatitis (26.2%), choroiditis with parasitic granulomatous vasculitis (26.2%), parasitic myocarditis (21.3%), gastritis with granulomatous vasculitis (19.8%) and adrenalitis with granulomatous vasculitis (4.9%). The anatomo-histopathological evaluation of the specimens' visual apparatus revealed predominantly neoplastic and inflammatory lesions, with fibropapillomatosis (FP) being the most frequent lesion (58.9%), followed by spirorchidiasis (46.8%). Other ophthalmic lesions included mucopurulent conjunctivitis, ulcerative keratitis, corneal perforation, panophthalmitis, phthisis bulbi, bilateral scar tissue in the eyelids and lithiasis in the salt glands. This study confirms the importance of knowing the pathological processes that affect sea turtles, such as those caused by anthropogenic action, parasitic infections or eye diseases, as these are changes that can directly impact the management and conservation of these species.