Paratuberculosis Infection in Bears and Lagomorphs:

• Mycobacterium avium subsp. paratuberculosis infection
• In cattle: Johne's disease

• This disease affects many species, especially ruminants. (B600.16.w16)
• Paratuberculosis or Johne's disease in domestic and wild ruminants is a disease with a protracted incubation period. It causes chronic diarrhoea and progressive weight loss, without fever, leading to emaciation. (B209.21.w21b)
• Most animals acquire the infection as neonates through the ingestion of milk or water that has become contaminated. Clinical infection may become apparent after several years of a prolonged subclinical phase. (B600.16.w16)

In Rabbits

Disease summary:

• Oral infection of neonatal rabbits can produce granulomatous enteritis and intermittent diarrhoea similar to that seen in cattle. (B600.16.w16)

Clinical findings:

• Affected wild rabbits may have good body condition. (B284.10.w10, J93.37.w1)
• With experimental infection in domestic rabbits:
  • There may be weight loss due to an absorption disorder. (B603.1.w1)
  • Intermittent diarrhoea may be seen. (B603.1.w1, B614.8.w8)

Pathological findings

Gross pathology

• A proportion of the affected wild rabbits that were surveyed had thickened areas of intestinal mucosa with the occasional granulomata. (B284.10.w10, B600.16.w16)
• Generally in good body condition. In three of 33 rabbits, intestinal mucosa (particularly terminal jejunum and ileum) thickened. (J3.140.w9)
• No gross pathological lesions noted. (J93.37.w1, J42.124.w2)

Histopathology

• Significant numbers of intracellular acid-fast bacilli are found in the lesions. (B284.10.w10)
• Granulomatous enteritis. (B603.1.w1)
  • Multifocal granulomas may be seen in the sacculus rotundus and caecum. (B614.8.w8)
• Intestines:
  • Intestinal lymphoid tissue containing small granulomas - large, pale-staining macrophage-like cells and some lymphocytes. These were the only lesions in 10 rabbits; acid-fast bacilli were detected in 5/10. (J3.140.w9)
  • Intestines: lamina propria infiltrated with epitheliod cells and multinucleate giant cells, villi thickened and distended with inflammatory cells, reduced numbers of intestinal crypts. Large numbers of acid-fast bacilli detected in lesions. In nine rabbits. (J3.140.w9)
    • Lesions of the intestinal lymphoid tissue were also seen in these rabbits. (J3.140.w9)
    • Mesenteric lymph nodes enlarged with epithelioid and giant cells infiltrating the cortical area and normal architecture of the nodes being lost; acid-fast bacilli detected by Ziehl-Neelsen staining. (J3.140.w9)
• Histopathological lesions, mild or severe, in 18/98 rabbits. (J42.124.w2)
  • Intestines: in 10 rabbits, severe lesions, villous lamina propria massively infiltrated with epitheliod macrophages and multinucleate giant cells, villi stunted and broadened. In three rabbits, mild lesions, with small aggregates of macrophage-like cells at the base of the lamina propria. Acid-fast bacilli (AFB) detected. (J42.124.w2)
  • Gut-associated lymphoid tissue: in the lymphoid patches, numerous epithelioid cells containing acid-fast bacilli. (J42.124.w2)
  • Sacculus rotundus and appendix: epitheliod macrophages aggregated, containing acid-fast bacilli. (J42.124.w2)
  • Mesenteric lymph nodes: (in the 10 rabbits with severe histopathological lesions of the intestines) in the cortex, many epitheliod and giant cells containing acid-fast bacilli. In the medulla, fewer such cells. In six other rabbits, small numbers of chronic inflammatory cells and very few AFB. (J42.124.w2)
  • Hepatic: (in the 10 rabbits with severe histopathological lesions of the intestines) mainly in periportal areas, multiple chronic inflammatory foci of lymphocytes, macrophages and multinucleate giant cells; AFB in the macrophages and giant cells. (J42.124.w2)
• Histopathological changes in 28 rabbits from farms with a history of Johne's disease and in 6 rabbits from farms without such a history; acid-fast bacilli found associated with the lesions in 10 and 2 rabbits respectively. (J93.37.w1)

In Bears

• During an examination of tissue sampled from 20 Ursus arctos - Brown bears from the central European Carpathian Mountains in Slovakia, Mycobacterium avium subsp. paratuberculosis was detected by PCR in the intestines of two bears. The isolates were confirmed by standardized IS900 restriction fragment length polymorphism (RFLP) analysis to be the same as that (RFLP type B-C1) detected in infected cattle in the same area. Additionally, acid-fast bacilli (visible by Ziehl-Neelsen staining) were detected in the kidney of one bear but were not isolated and were probably environmental. (J1.42.w1)

In Rabbits

Occurrence in wild lagomorphs

• Reported in wild Oryctolagus cuniculus - European rabbit in Scotland. (B209.21.w21b)
  • In one rabbit, chronic intestinal lesions: thickening of the mucosa, particularly in the terminal ileum, which appeared rugose. Histologically, widespread lamina propria infiltration with large cells, pale staining, resembling epithelioid macrophages, associated distention of villi and some loss of crypts. Numerous intracellular acid-fast bacilli were found in the lesions. No similar lesions, nor acid-fast bacilli, were detected in a further 29 rabbits from the same area. (J42.103.w1)
  • One survey of wild rabbits in Tayside, Scotland, UK, found 67% were infected with Mycobacterium avium  subspecies paratuberculosis. The high incidence of this infection in wild rabbits was thought to be linked with a high prevalence of paratuberculosis in cattle. (J3.140.w9)
  • A further epidemiological study found a statistically significant relationship between a present or previous paratuberculosis problem in cattle on farms and the presence of paratuberculosis in rabbits on the same farms. On three of the 14 farms with a history of Johne's disease, 8 - 53% of sampled wild rabbits were infected. Mycobacterium avium subsp. paratuberculosis was also cultured from one rabbit from a farm without any history of Johne's disease. (J93.37.w1)
  • Another Scottish survey, of rabbits on or adjacent to farms affected by paratuberculosis in ruminants, found evidence of infection in 22% of 110 rabbits, with the organism cultured from 17 of the rabbits and histopathological lesions consistent with infection seen in 18/98 rabbits. (J42.124.w2)
  • Mycobacterium avium subspecies paratuberculosis was also identified in foxes and stoats that were collected from affected farms. (J3.145.w7)
• Isolation of a mycobacterium resembling Mycobacterium avium subspecies paratuberculosis (but not definitely identified) from one Lepus europaeus - Brown hare. Four other isolates were identified as Mycobacterium avium. (J35.133.w1)

Treatment

• Rifampin is reportedly helpful in treating experimentally induced Mycobacterium avium infection in rabbits; however, it is not curative. (B614.8.w8)

• Environmental Assessment
• History & Documentation
• Physical Examination of Mammals
• Necropsy of Mammals
• Imaging in Lagomorph Diagnosis and Treatment
• Clinical Pathology of Lagomorphs
• Treatment and Care
• Environmental and Population Management
• Preventative Medicine for Mammals
• Chapter 2 - B36 Field Manual of Wildlife Diseases - Specimen Collection and Preservation
• Chapter 3 - B36 Field Manual of Wildlife Diseases - Specimen shipment
• Appendix A - B36 Field Manual of Wildlife Diseases - Sample specimen history form

• Bears (Ursidae - Bears (Family))
  • Ursus arctos - Brown bear
• Lagomorphs 
  • Lepus europaeus - Brown hare
  • Oryctolagus cuniculus - European rabbit

(List does not contain all other species groups affected by this infectious agent)