Testicular degeneration in a jaguarundi (Puma yagouaroundi): a histological and functional case study

A free-ranging adult male jaguarundi (Puma yagouaroundi) was referred to a wildlife rehabilitation center after sustaining blunt trauma caused by a vehicle collision and died one month later. Following death due to trauma-related complications, a targeted post-mortem examination focused on the reproductive system and laboratory analyses were conducted to evaluate potential reproductive abnormalities. Macroscopic examination of the testis revealed no external alterations. However, histopathological evaluation confirmed moderate bilateral testicular degeneration, characterized by reduced seminiferous tubule diameter and epithelial height, vacuolization, germ cell loss, and premature shedding of immature cells into the lumen and epididymis. Approximately 70% of tubules were atrophic, although some retained limited spermatogenic activity. Epididymal sperm analysis revealed poor motility, reduced viability, and impaired plasma and acrosomal membrane integrity, along with a high proportion of morphological abnormalities. These findings were consistent with impaired spermatogenesis and functional compromise. No inflammatory infiltrates were observed, supporting a non-inflammatory, likely trauma-related etiology. To our knowledge, this is the first report documenting testicular degeneration in P. yagouaroundi. These findings contribute to understanding reproductive pathology in wild felids and underscore the importance of routine reproductive assessment in conservation efforts.