Dioctophyme spp

From Dog
Adult Dioctophyme renale worms within the urinary bladder[1]
Light micrograph of Dioctophyme renale ovum and struvite crystals from canine urolith[2]

Dioctophyme are a parasitic enoplid nematode of dogs in North and South America[3].

The prepatent period is about 135 days in the dog[4].

Species which are pathogenic include:

  • Dioctophyme renale

These worms have a specialized life cycle, and the dog large kidney worm, D. renale affects dogs, pigs and sometimes humans. The mink is considered the definitive host for this parasite.

These worms may reach 1 meter in length and produce brownish, thick-shelled characteristic eggs. The eggs are passed in the urine and feces (in adults that fail to penetrate the intestine, and subsequently develop in water, infecting oligochaete annelid worms. The infective larvae are then ingested by dogs, and migrate out of the intestine lumen, and reside either within the peritoneal cavity (non-patent), urinary bladder[5] or renal pelvis. Usually the right kidney is affected, but both can be parasitized[6].

These worms can be found free-floating in the peritoneum and appear to be relatively non-pathogenic, although peritonitis can be a sequel in heavy burdens. Adult worms can survive up to five years[7].

Clinical signs in affected dogs include an insidious dysuria and hematuria which often fails to resolve after routine antimicrobial therapy. Renal pain, fever and peritonitis may be present in acute cases of secondary pyelonephritis.

Diagnosis is based on identification of eggs in feces and ultrasonographic finding of enlarged renal pelvis or space-occupying mass within the urinary bladder[8]. Generally, in almost all cases, parasitism by D. renale in domestic dogs is a necropsy finding[9].

Successful intervention usually requires surgical removal of adult D. renale from the renal pelvis or bladder via laparotomy.

Treatment with antiparasiticides is not thought to be effective, although there is one report of ivermectin being effective against D. renale in a human[10].

References

  1. Nematode 2011
  2. Whelen JC et al (2011) Ova of Dioctophyme renale in a canine struvite urolith. Can Vet J 52(12):1353-1355
  3. Pereira BJ et al (2006) The occurrence of dioctophymosis in dogs from Municipality of Cachoeiro do Itapemirim in the State of Espírito Santo, Brazil, from May to December of 2004. Rev Bras Parasitol Vet 15(3):123-125
  4. Measures, LN (2001) Dioctophymatosis In: Parasitic diseases of wild mammals. Iowa State University Press, Ames. pp:357-364
  5. Nakagawa TL et al (2007) Giant kidney worm (Dioctophyma renale) infections in dogs from Northern Paraná, Brazil. Vet Parasitol 145(3-4):366-370
  6. Bowman, DD (2009) Georgis' parasitology for veterinarians. 9th edn. Elsevier Saunders, Missouri. pp:221-222
  7. Ferreira VL et al (2010) Dioctophyme renale in a dog: Clinical diagnosis and surgical treatment. Vet Parasitol 168:151–155
  8. Soler M et al (2008) Imaging diagnosis--dioctophyma renale in a dog. Vet Radiol Ultrasound 49(3):307-308
  9. Ferreira VL et al (2010) Dioctophyma renale in a dog: clinical diagnosis and surgical treatment. Vet Parasitol 168(1-2):151-155
  10. Ignjatovic I et al (2003) Infestation of the human kidney with Dioctophyme renale. Urol Int 70:70–73