Dracunculus spp

From Dog
Drcunculus larvae extracted from a dog[1]

Dracunculus spp (Guinea worm) are a hematophagous spirurid nematode parasite of dogs and cats in North Africa, the Middle East, India, Asia and the Americas[2].

Species which are pathogenic to dogs include:

  • Dracunculus insignis

These worms have a life cycle which involves a freshwater copepod (Cyclops spp). Dogs become infected by ingesting copepods in drinking water. Turtles and snakes are also definitive hosts. Dogs can acquire this parasite, where the larvae develop within a pseudocyst in the subcutaneous tissue of the abdomen and limbs[3].

Affected dogs present with painful, fluctuant subcutaneous swellings on the limbs and ventral abdomen, often after swimming in fresh water ponds. Focal areas of erythema and pyoderma are usually associated with the nodules[4].

The nodules eventually develop a fistula, through which the larvae escape. The female worm is stimulated to release larvae when the host enters cold water. The lesions are often painful and pruritic[5].

Diagnosis is based on extraction and identification of the worm or visualization under histological biopsy[6].

Treatment is usually effective with diethylcarbamazine, selamectin, doramectin and ivermectin but long term treatment is required to eradicate adult worms.

References

  1. Kansas State University
  2. Hoyos CB et al (1993) Report of a case of dracunculosis in a dog in the Province of Formosa - Argentina. Rev Inst Med Trop Sao Paulo 37(3):273-275
  3. Bowman, DD (2009) Georgis' parasitology for veterinarians. Elsevier Saunders, Missouri. pp:208-209
  4. Panciera DL & Stockham SL (1988) Dracunculus insignis infection in a dog. J Am Vet Med Assoc 192(1):76-78
  5. Beyer TA et al (1999) Massive Dracunculus insignis infection in a dog. J Am Vet Med Assoc 214(3):366-368
  6. Langlais L (2003) Dracunculosis in a German shepherd dog. Can Vet J 44(8):682