Canis ISSN: 2398-2942

Pythiosis

Contributor(s): Rhea Morgan

Introduction

  • Cause:Pythium insidiosum(formerly known asHyphomyces destruens,Pythium destruens,Pythium gracilePythium insidiosum.
  • Signs: cutaneous and gastrointestinal signs.
  • Diagnosis: serology, PCR assay, histopathology.
  • Treatment: surgical excision, itraconazole Itraconazole with or without terbinafine Terbinafine.
  • Prognosis: poor.

Pathogenesis

Etiology

  • Pythium insidiosuman oomycete.
  • Oomycetes are soil or water saprophytes.
  • They are not true fungi.
  • They produce motile flagellate zoospores, which are the infective stage.
  • Their plasma membranes lack sterols, which is the site of activity of many antifungal drugs.

Predisposing factors

General

General

  • Residing or traveling in an area where the organism is endemic.
  • Contact with warm, stagnant water containing the infective stage.

Specific

  • Seasonal occurrence, with most cases diagnosed between August and December (in the United States).
  • Corticosteroid administration results in rapid dissemination of the disease.

Pathophysiology

  • The organism may gain entrance to the body through breaks in the skin or by invading the gastrointestinal mucosa following ingestion.
  • Gastrointestinal disease is the primary clinical manifestation.
  • The organism has a predilection for the stomach, duodenum and ileum, causing an infiltrative granulomatous gastroenteritis Enteritis: granulomatous.
  • Isolated masses may develop within the gastrointestinal tract.
  • Cutaneous lesions begin as focal nodules that rapidly enlarge and become destructive to near by tissues.
  • Necrosis of the skin and subcutaneous tissues may result.
  • Large, spongioform lesions with multiple draining tracts are common.
  • Some lesions involve the entire circumference of the affected limb.
  • Cutaneous lesions are not often accompanied by gastrointestinal infection.

Timecourse

  • Incubation poorly defined.
  • Duration is weeks to months.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Graham J P, Newell S M, Roberts G D, Lester N V (2002) Ultrasonographic features of canine gastrointestinal pythiosis. Vet Radiol Ultrasound 41 (3), 273-277 PubMed.
  • Grooters A M, Leise B S, Lopez M K et al (2002) Development and evaluation of an enzyme-linked immunosorbent assay for the serodiagnosis of pythiosis in dogs. J Vet Intern Med 16 (2), 142-146 PubMed.
  • Znajda N R, Grooters A M, Marsella R (2002) PCR-based detection of Pythium and Lagenidium DNA in frozen and ethanol-fixed animal tissues. Vet Dermatol 13 (4), 187-194 PubMed.
  • Fischer J R, Pace L W, Turk J R et al (1994) Gastrointestinal pythiosis in Missouri dogs eleven cases. J Vet Diagn Invest 6 (3), 380-382 PubMed.

Other sources of information

  • Taboada J (2002)Systemic mycoses.In: Morgan R V, Bright R N, Swartout M S (eds)Handbook of Small Animal Practice. 4th Ed. W B Saunders, Philadelphia, pp1072-1089.
  • Foil C S (1998)Miscellaneous fungal infections.In: Greene C E (ed)Infectious diseases of the Dog and Cat.2nd Ed. W B Saunders, Philadelphia, pp 420-430.


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