Canis ISSN: 2398-2942

Colitis: parasitic / infectious

Contributor(s): Audrey K Cook, James Simpson

Introduction

 
  • CauseTrichuris vulpisGiardiaIsospora spp, Campylobacter, Clostridium spp and Salmonella most common in UK.
  • Signs: increased frequency of defecation with fecal tenesmus, stools often contain blood and mucus.
  • Diagnosis: identification of causal agent.
  • Treatment: depends on causal agent.
  • Prognosis: generally good.

Pathogenesis

Etiology

Predisposing factors

General

  • Stress.
  • Juveniles.
  • Unhygienic, crowded conditions.

Pathophysiology

Note: all these organisms can be found in clinically normal dogs; the presence of these agents does not automatically indicate a causal relationship.

Salmonella spp

  • Mucosal invasion → mucosal damage.
  • Also stimulates intestinal secretion.

Campylobacter jejuni

  • Invades mucosa → mucosal damage.

Trichuris vulpis

  • Migration of larvae → chronic inflammatory cellular infiltrate in lamina propria → mucosal hyperplasia.

Giardia duodenalis

  • Trophozoites attach to epithelium → mechanical, toxic or immunological mucosal damage.
  • More commonly seen in small intestine but clinical signs of colitis may be noted.

Clostridium perfringens

  • Enterotoxin released during sporulation → mucosal damage, increased intestinal permeability.

Isospora

  • Sporozoites invade intestinal wall.

Timecourse

Salmonella spp

  • 3-10 days incubation.

Campylobacter jejuni

  • 1-7 days incubation.

Trichuris vulpis

  • 2-8 weeks incubation.

Giardia

  • 6-8 days incubation.

Clostridium perfringens

  • N/A: Normal inhabitant of canine GI tract.

Isospora spp

  • 3-10 days incubation.

Epidemiology

Salmonella

  • Contaminated food and water most likely source of infection.
  • Fairly resistant outside host.
  • Isolated from normal dogs and cats - development of disease dependent on age, stress and status of immune system.
  • Zoonotic potential.

Campylobacter jejuni

  • Isolated from normal dogs and dogs with diarrhea.
  • Contaminated food and water likely source of infection.
  • Zoonotic potential.

Trichuris vulpis

  • Feco-oral route of infection.
  • Development of disease depends on number of parasites and may be precipitated by stress.

Giardia duodenalis

  • Feco-oral ingestion of resistant cysts from contaminated food/water.
  • Zoonotic potential.

Clostridium perfringens

  • Routinely present in canine GI tract.
  • Sporulation and release of enterotoxin triggered by change in colonic microenvironment.

Isospora spp

  • Feco-oral ingestion of sporulated oocysts from contaminated environment.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Wilcock B (1992) Endoscopic biopsy interpretation in canine or feline enterocolitis. Semin Vet Med Surg (Small Animal) (2), 162-171 PubMed.


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