Mesothelial metaplasia in European pond turtle, Emys orbicularis (Testudines: Emydidae) infected with Spiroxys contortus (Nematoda: Spirurida)

The mesothelium consists of a monolayer of specialized epithelial cells that line the surfaces of the peritoneal, pleural, and pericardial cavities. The present study reports mesothelial changes associated with larval stages of the spirurid nematode Spiroxys contortus in a naturally infected European pond turtle. Between 2002 and 2007, eight European pond turtle, Emys orbicularis were brought for necropsy. In one adult male turtle, necropsy revealed the presence of gastric and mesothelial changes associated with gastric infestation with the nematode Spiroxys contortus. Gastrointestinal samples with gross lesions were collected and processed by paraffin technique for further histological examination. Mesothelial cuboidal to columnar or pseudostratified focal progressive metaplasia was observed in visceral coelomic cavity. Intracytoplasmic acidophilic hyaline inclusions were also observed in metaplastic mesothelial cells, most of them being placed to the apical cell’s poles. The significance of our findings is discussed in the light of current knowledge regarding the mesothelial cells.