Giant Kidney Worm

(Dioctophyme renale)

The giant kidney worm is a parasitic nematode that locates in the right kidney, which may result in destruction of the functional tissue or within the peritoneal cavity.

Parasite: Dioctophyme renale
Common name: Giant kidney worm
Host: Dogs, mustelids, cats, humans
Pre-patent period: 2 to 6 months
Location of adults: Right kidney, peritoneal cavity
Distribution: Worldwide
Transmission route: Oral [ingestion of intermediate (oligochaete annelid; “aquatic worms”) or paratenic hosts (fish or frogs)]
Zoonotic: Yes


Dioctophyme renale is found worldwide, except in Africa and Oceania.

Clinical signs

Many dogs are asymptomatic due to compensatory hypertrophy of the unaffected kidney. Clinical signs may include haematuria, right kidney pain, right limb claudication, lumbar and abdominal pain and potentially paresis of the hind quarters. If the left kidney is also compromised, the dog will develop clinical signs of renal failure such as polydipsia and polyuria. Worms migrating within in the peritoneal cavity may produce abdominal pain.


Eggs are passed via the ureteral lumen into the urine if there is at least one female worm present in the kidney. Brownish, thick-shelled eggs with bipolar pigs (68 x 45 μm) containing a single cell, can be detected by the examination of urine sediment under light microscopy. If the slide is covered with red cells they should be removed by means of acetic acid to enable visualisation of the eggs. Ultrasound can be used to visualise the worms within the kidney or peritoneum. Dioctophyme worms are red, the female can reach 1 m in length and 1 cm in diameter.


Surgical removal of the worm is the only current treatment option.


Do not allow dogs to drink from fresh-water bodies or ingest aquatic worms or frogs. Dogs should not be fed raw fish.

Public health considerations

Humans get infected in the same way as dogs, most commonly by ingesting undercooked fish and frog.