Maria A. da Silva1; Rachel B. Ribeiro1; Hassan J. Leandro1; Raphael M. Medina1; Eulógio C.Q. de Carvalho1; Max R. Werneck2
Abstract
Five sea turtle species live in the Brazilian ocean waters: Chelonia mydas, Caretta caretta, Eretmochelys imbricata, Lepidochelys olivacea and Dermochelys coriacea. Of these, E. imbricata is considered critically endangered.5 Spirorchiids (Digenea: Spirorchiidae) are a group of trematodes that colonize the circulatory system of turtles. The family has approximately 100 species grouped into 19 genera,6 ten of which parasitize sea turtles8. The parasitic infestation by spirorchiids causes inflammatory lesions due to the eggs deposited in the blood stream, embolism, and tissue accumulation,1,7,9 which can contribute to or even cause the host's death4. In 2011, tissue samples from eight dead E. imbricata individuals were analyzed. Animals presented curved carapace length between 33.0 and 35.5 cm and were found dead, stranded on the beach, or died during treatment, in the states of Espírito Santo and Rio de Janeiro, Brazil. Samples of internal organs were collected, fixed in buffered formalin 10% for at least 48 h and then paraffin-embedded. Histopathological analyses revealed the presence of giant cell granulomas in four animals (50%), similar to a foreign body, involving spirorchiid eggs. Granulomas were observed in the intestines of two animals, in the stomach of one, and in the liver of another. In one animal, granulomas were widely distributed. It should be stressed that one animal exhibited granulomatous enteritis and hepatitis. This occurrence was considered an incidental finding,9 and these cases cannot affirm that the eggs were responsible for the death of these turtles. Pathological changes induced by spirorchiid eggs have been reported in C. mydas and C. caretta in different parts of the world,1,4,7,9 and in E. imbricata3. However, in Brazil, the only report published described spirorchiidiosis in a juvenile E. imbricata individual.2 All findings observed in the present study were compatible with spirorchiidiosis and agree with previous results published in studies about sea turtles.1,4,7,9 Although the histopathological analysis in sea turtles is not commonly carried out in Brazil, the findings reported here are very important in the evaluation of animals, and may be valuable in conservation biology initiatives for sea turtles in the region.
Acknowledgements
The authors wish to thank Dr. Bruno Berger, of the company CTA - Meio Ambiente, and Dr. Cecília Baptistotte, of Projeto TAMAR - ICMbio, for allowing to use the samples analyzed in the present study.
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