DISEASE SUMMARY PAGE

Lawsonia intracellularis Infection in Rabbits

Summary Information
Diseases / List of Bacterial Diseases / Disease summary
Alternative Names
  • Campylobacter-like bacterial infection in rabbits
  • Proliferative enteropathy in rabbits.
Disease Agents Lawsonia intracellularis, an obligate intracellular parasite.
  • Formerly known as "Campylobacter-like organism". (J26.27.w1, J495.46.w2)
  • This organism is also the primary pathogen in porcine intestinal adenomatosis. (J495.46.w2)
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s) --
General Description
Clinical signs
  • Lethargy and inappetance. (J26.27.w1)
  • Diarrhoea.(J26.27.w1, J27.66.w2, J27.70.w1)
    • Faeces mucoid and semi-fluid. (J26.27.w1)
    • With associated weight loss. (J27.70.w1)
  • Infection can be subclinical. (J26.35.w1)
  • Dual infection with Escherichia coli resulted in unexpectedly high mortality. (J93.36.w3)
Pathological findings

Gross pathology

  • In rabbits with clinical disease:
    • GIT: Proliferative lesions of the small intestine, caecum and colon and/or suppurative or erosive and suppurative caecocolitis.  (J26.27.w1)
  • In seven- to eight-week-old sentinel rabbits with subclinical disease: (J26.35.w1)
    • GIT: Distal ileum wall thickened; the mucosa was thickened and corrugated. (J26.35.w1)
  • In rabbits with diarrhoea:
    • Dehydrated carcasses, emaciation (scanty subcunaeous and intra-abdominal fat). (J27.70.w1)
    • GIT: mucosa of the small intestine (jejunum to ileum) severely thickened. (J27.70.w1)
    • Lymph nodes: enlarged mesenteric lymph nodes. (J27.70.w1)

    Histopathology

    • In rabbits with clinical disease:
      • GIT: In the small intestine, caecum and colon, multifocal to diffuse epithelial cell proliferation and lamina propri accumulation of lymphocytes and/or macrophages. In some of these rabbits, and in  others without proliferative lesions, suppurative or erosive and suppurative caecocolitis. (J26.27.w1)
      • In affected tissues, staining with Warthin-Starry stain showed curved or spiral intracellular bacteria. (J26.27.w1)
      • Immunohistochemical staining with monoclonal or polyclonal antibodies against the agent of proliferative enteritis in pigs, hamsters and ferrets showed Campylobacter-like bacteria within the epithelial cells. (J26.27.w1)
    • In seven- to eight-week-old sentinel rabbits with subclinical disease: (J26.35.w1)
      • GIT: Ileal mucosa thickened, with epithelial cell hyperplasia of villae and crypts. Also blunting and fusion of villi. (J26.35.w1)
        • In enterocytes of villi and crypts, clusters of slightly curved rods within the cytoplasm of enterocytes in hyperplastic areas. The intracellular organisms were argyrophilic with Warthin-Starry stain. Identity of the organism confirmed by immunohistochemical staining with a Lawsonia intracellularis-specific monoclonal antibody of porcine origin. (J26.35.w1)
    • In rabbits with diarrhoea:
      • GIT: Hyperplasia and degeneration of the epithelium of the small intestine, with severe inflammatory infiltration of the lamina propria (lymphocytes, heterophils, macrophages and multinucleate giant cells). Epithelial cells showed variations in the positioning of their nuclei, reduction in cell height, and microvilli were absent; additionally, "crypt-abscess" and reduced goblet cell density. (J27.70.w1)
        • In the juvenile rabbit, the mucsa appeared granulomatous due to severe thickening with an infiltration of macrophages and giant cells. (J27.70.w1)
        • With Warthin-Starry silver stain, numerous intracellular curved bacilli in the luminal edge of the epithelium and in macrophages in the lamina propria. (J27.70.w1)
      • Mesenteric lymph nodes: follicular hyperplasia, peripheral histiocytosis. (J27.70.w1)
Further Information
Diagnosis
  • Presence of the intracellular organism in enterocytes in histologically visible affected areas of the GIT; increased visibility with Warthin-Starry stain. (J26.27.w1, J27.70.w1)
  • Immunohistochemical staining of affected gut sections. (J26.27.w1, J26.35.w1, J27.66.w2, J27.70.w1)
  • PCR of faecal samples (J27.66.w2) and of samples from affected intestine. (J27.70.w1)
  • ELISA. (J27.66.w2)
Occurrence in lagomorphs
  • Seen in suckling rabbits, weanlings and young adults. (J26.27.w1)
  • Detected in a six-week-old female New Zealand white rabbit with diarrhoea. (J27.66.w2)
  • Seen in adult Oryctolagus cuniculus - European rabbits housed in a field at a wildlife park in Japan, and in a conventionally-housed three-month-old female rabbit. (J27.70.w1)
Associated Techniques
Host taxa groups /species
Disease Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referees William Lewis BVSc CertZooMed MRCVS (V.w129)

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