Renal dioctophymosis in a free-ranging lesser grison (Galictis cuja): antemortem diagnosis and nephrectomy

Abstract Dioctophymosis is caused by Dioctophyme renale , a nematode that primarily affects the right kidney of domestic and wild mammals. This report describes the antemortem diagnosis, surgical treatment, and rehabilitation of a free-ranging lesser grison ( Galictis cuja ) infected with the parasite. An adult male weighing 1.85 kg was admitted after being struck by a vehicle and showed signs consistent with traumatic brain injury. During hospitalization, fecal parasitological examination revealed eggs consistent with D. renale , along with other parasitic structures. Urinalysis revealed mild proteinuria, hematuria, leukocyturia, marked bacteriuria, and numerous D. renale eggs. Abdominal ultrasonography showed multiple tubular and circular structures in the right kidney region, consistent with parasites, with no residual renal parenchyma identified. The left kidney was enlarged and showed mild changes in echogenicity. Given the extent of renal involvement, a right nephrectomy was performed, resulting in the removal of eight adult D. renale specimens, comprising seven females and one male. Histopathological examination confirmed complete destruction of the renal parenchyma, absence of viable glomeruli and tubules, and osseous and squamous metaplasia of the renal capsule. Serial hematological and biochemical evaluations showed no progressive increase in urea or creatinine concentrations. Postoperative recovery was uneventful, allowing the animal to recover and return to the wild. This case highlights the importance of combining urinalysis, ultrasonography, and clinical evaluation for the diagnosis and therapeutic planning of dioctophymosis in wild mustelids.