Case 3 Answer


  1. (d) The histopathology and special staining enabled a tentative diagnosis of gastrointestinal pythiosis or mucormycosis in this case.
  1. (d) PCR will provide a definitive diagnosis and in this case confirmed the fungus to be Pythium insidiosum. (b) Alternatively, a soluble mycelial antigen-based ELISA or western blot analysis may be used to detect insidiosum antibodies in the serum.



  1. Pythium is identified most often in young, male, large breed dogs with recurrent exposure to warm freshwater habitats. Some infections develop in suburban house dogs with no known access to a standing body of water.
  1. In dogs, gastrointestinal or cutaneous disease may be present, but are rarely found together in the same animal. Pythium has also been described as an uncommon cause of cutaneous or subcutaneous lesions in cats.
  1. In dogs, gastrointestonal pythiosis typically results in clinical signs of weight loss, vomiting, diarrhoea and haematochezia in association with a palpable abdominal mass on physical examination. Haematological and serum biochemical abnormalities may include anaemia, eosinophilia, hyperglobulinaemia and hypoalbuminaemia.
  1. Cutaneous lesions consist of non-healing wounds and invasive masses that contain ulcerated nodules and draining tracts.
  1. Most frequently the disease involves the gastroduodenal and ileocolic sections of the GI tract. However, multisegmental lesions and diffuse involvement of the GI tract have been described. Infection may extend directly to adjacent tissues including the mesenteric lymph nodes, blood vessels, pancreas, uterus and prostate.
  1. Accordingly, the prognosis in most patients with GI pythiosis is guarded to grave.
  1. Infections caused by insidiosum are acquired from the environment. No evidence suggests transmission between hosts.