Physaloptera spp

From Dog
Egg of Physaloptera spp
Adult female Physaloptera spp worm

Physaloptera spp are a parasitic nematode of the dog stomach[1], with prevalence rates of 1 - 5 % worldwide[2].

Species which are pathogenic to dogs include:

  • Physaloptera praeputialis

Several species of these stomach nematodes of dogs are seen throughout the world. They are usually firmly attached to the gastric or duodenal mucosa. The males are ~30 mm and the females ~40 mm long. The eggs are oval, 32 × 55 µm, thick-shelled, and larvated[3].

Encysted infective larvae of Physaloptera spp have been found in several species of insects, including beetles, cockroaches, and crickets. Mice and frogs may be paratenic hosts. After the dog ingests the intermediate or paratenic host, development of larvae to adults is direct.

Clinical signs in urban dogs are often absent, although vomiting, anorexia and melena associated with gastritis is common[4].

In heavy infections, anemia and weight loss may develop[5].

Diagnosis is usually based on presenting clinical signs and coprological identification of Physaloptera eggs. Endoscopic examination of the stomach may assist in diagnosis[6].

A differential diagnosis would include other nematode infections (e.g. Spirocerca spp) and coccidian protozoa such as Neospora spp or Giardia spp.

Treatment is usually effective with fenbendazole (50 mg/kg orally once daily for 3 days), febantel (5 mg/kg orally once) or ivermectin (0.2 mg/kg orally).


  1. Santos JL et al (2012) Parasites of domestic and wild canids in the region of Serra do Cipó National Park, Brazil. Rev Bras Parasitol Vet 21(3):270-277
  2. Nonaka N et al (2011) Coprological survey of alimentary tract parasites in dogs from Zambia and evaluation of a coproantigen assay for canine echinococcosis. Ann Trop Med Parasitol 105(7):521-530
  3. Merck Veterinary Manual
  4. Clark JA (1990) Physaloptera stomach worms associated with chronic vomition in a dog in Western Canada. Can Vet J 31(12):840
  5. Theisen, SK et al (1998) Physaloptera infection in 18 dogs with intermittent vomiting. J Am Anim Hosp Assoc 34(1):74-78
  6. Theisen SK et al (1998) Physaloptera infection in 18 dogs with intermittent vomiting. J Am Anim Hosp Assoc 34(1):74-78