Spirorchiidiasis in Stranded Olive Ridley Turtles (Lepidochelys olivacea) Along the Northern and Central-Northern...

The olive ridley turtle (Lepidochelys olivacea) is the second smallest and most abundant of the seven sea turtle species worldwide, currently distributed across approximately 80 countries. However, due to various anthropogenic and environmental pressures, its populations are declining and categorized as "Vulnerable" by the IUCN. Postmortem macroscopic and microscopic examination detected spirorchiids and associated lesions in six adult female olive ridley turtles is described herein, with strandings occurring along the Northern and Central-Northern Chilean coast between September 2024 and January 2026. Gross findings included alterations in the gastrointestinal, reproductive, and vascular systems, characterized by transmural granulomatous lesions and mucosal thickening. Histopathological analysis confirmed the presence of these cryptic parasites in multiple organs, including the intestine, reproductive tract, vasculature, liver, spleen, and adrenal glands, with varying degrees of severity. These findings confirm the presence of spirorchiidiasis in olive ridley turtles in Chile, which may have contributed to stranding and mortality events in some individuals. Molecular characterization is essential to determine whether this agent corresponds to a known species or represents a previously unreported spirorchiid taxon in the Southeastern Pacific.