Microscopic characterization of Sarcocystis sp. in the esophagous of a llama (Lama glama) from Jujuy, Argentina

Abstract

Sarcocystis sp. are protozoa that affect numerous intermediate hosts, forming cysts in skeletal or cardiac muscle. In llamas (Lama glama), S. aucheniae (macrocysts) and S. masoni (microcysts) have been described in skeletal muscle and skeletal and cardiac, respectively. However, the presence of macroscopic cysts in smooth muscle, such as the esophagus, has been little documented in this species. In sheep (Ovis aries), on the other hand, the presence of macroscopic cysts of S. gigantea located in the esophagus has been reported, suggesting differences in tissue distribution between species. The aim of the present work was to characterize morphologically macroscopic cysts of Sarcocystis sp. found in the esophagus of a llama in Jujuy, Argentina. The complete esophagus was collected from a llama slaughtered in Jujuy, Argentina. Macroscopic cysts were measured and processed for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Macroscopic cysts were identified as 7-12 mm, white to pale yellow, oval or fusiform in shape, located superficially or embedded in esophageal tissue. SEM and TEM analysis showed a smooth primary cystic wall 5-10 μm thick and an amorphous and homogeneous internal ground substance. Bradyzoites were observed in sacs separated by septa, with dimensions of 5-9 μm in length and 1.5-2.5 μm in width. The results suggest that the morphological and ultrastructural features observed are consistent with previous descriptions of S. aucheniae and S. gigantea. This work reports macroscopic cysts of Sarcocystis sp. in the esophagus of Lama glama, extending the knowledge about their tissue distribution and diagnostic relevance in South American camelids.