Giant Kidney Worm - Bob

‘Monsters’ inside our dogs? Rare, but true!

Kidney WormBob, who is now a 2 year old lab, presented to Seattle Veterinary Specialists in 2015 as a transfer from his veterinarian at Redmond-Kirkland Animal Hospital for further work up of blood in his urine (hematuria) and the finding of parasite eggs in his urine.  Once at SVS, an abdominal ultrasound was performed by Alaina Carr DVM, ACVR who described changes consistent with a giant kidney worm of the right kidney and associated focal peritonitis (inflammation) and effusion (fluid). Many parasitic infections can be treated medically (with medicine), however with Dioctophyma renale, the treatment of choice is surgical excision of the affected kidney as considerable kidney damage has typically occurred prior to diagnosis. 


Bob was taken to surgery by Byron Misseghers DVM, DACVS and Stephen Stockdale, DVM (surgery resident). At the time of surgery, once the abdomen was opened, a free floating worm parasite was found and removed. The right kidney was isolated identifying obvious lengths of parasite weaving into the capsule of the kidney.  A right nephrectomy was performed. Bob recovered well from anesthesia and surgery.  He was discharged about 2 days post operatively.

A heart-touching feature story was done by the Kirkland detailing a bit of Bob’s story, his current status, and his relationship with his family.

Dioctophyma renale is rare in the PNW.  The life cycle of the parasite involves an intermediate host (largely, raw crayfish, frogs or fresh water fish) and a definitive host (carnivorous mammals such as dog, wolf, coyote, mink).  An infected dog (definitive host) urinates parasite eggs into a body of water, the intermediate host eats the parasite.  An intermediate life cycle stage lives in the fish/crayfish/frog. A dog eats the raw intermediate host infected with an immature life stage of the parasite.  The parasite matures and migrates to the kidney (typically only one kidney involved).  In the kidney, as it grows, it weaves through and destroys kidney tissue.  This destruction leads to bloody urine and clinical signs.

D. renale is considered a zoonotic disease (may infect humans), however human cases are rare and may be avoided by cooking intermediate host meat well (so cook your cray fish, frogs and fresh water fish!).