Actinobacillus Infection in Waterfowl and Lagomorphs

Disease Summary

• In reference to rabbits: "Several cases of soft tissue swelling and inflammation around the joints of the extremities have been attributed to Actinobacillus spp." (B614.8.w8)
• Hares: Actinobacillus capsulatus has been recovered from the visceral organs of Lepus americanus - Snowshoe hare. (B614.8.w8)

Alternative Names (Synonyms)

• In lagomorphs, see also Septic Arthritis in Rabbits

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

Infective "Taxa"

• Actinobacillus capsulatus
• Actinobacillus suis
• Actinobacillus spp.

Non-infective agents

Physical agents

References

Disease Author

Referees

Major References / Reviews

Code and Title List

Lagomorphs:
B614.8.w8
J1.24.w12, J1.26.w13, J42.72.w2, J212.17.w2, J350.9.w1

Other References

Code and Title List

Detailed Clinical and Pathological Characteristics

General

Clinical Characteristics

• Septicaemia - sudden onset gasping, neck-swaying and death (J1.15.w5).
• Ocular - serous periocular discharge (J1.13.w8); greyish tenacious exudate matting eyelids closed (J1.23.w4).
• Respiratory - clinical signs not described (J6.24.w1).
• Oviduct - clinical signs not described (J6.24.w1).

(J1.13.w8, J1.15.w5, J6.24.w1, B15)

• A Lepus americanus - Snowshoe hare in Alaska was noted to show abnormal behaviours including sluggish movements and reduced fear of humans and dogs. (J1.24.w12)

In rabbits with septic arthritis:

• Soft tissue swelling and inflammation around limb joints in rabbits. (B614.8.w8)
  • Initial reddening around the joint. (J350.9.w1)
  • Swelling, increasing in size, around the joint. (J350.9.w1)
  • Yellowish swellings visible under thin skin, exuding glutinous yellowish pus when the skin surface was broken or became ulcerated. (J350.9.w1)
  • In one rabbit, "indurated swellings with areas of caseation around the digits" (J42.72.w2)
  • Progressive emaciation. (J350.9.w1)
  • Death after several months. (J350.9.w1)
  • Note: a similar tarsal joint lesion developed following intravenous inoculation of the organism. (J42.72.w2)

In a rabbit with septicaemia:

• Anorexia and depression for three days. (J212.17.w2)
• Stomach doughy and filled with ingesta. (J212.17.w2)
• Fever (41.0 °C) and panting. (J212.17.w2)
• Death a few hours after the initiation of treatment. (J212.17.w2)
• [Note: many of the signs were consistent with gastric stasis syndrome; acute septicaemia was also diagnosed]

Experimental inoculation in rabbits:

• Following subcutaneous inoculation, local caseaus subcutaneous abscesses. (J42.72.w2)
• Following inoculation into the tarsal joint, acute fluctuating abscess, caseous infection in periarticular tissues, then gradual decrease in the size of the affected area. (J42.72.w2)
• Following intravenous inoculation, development of joint abscesses - on the knee of one animal and the tarsal joint of the other. In the rabbit with the knee lesion, also emaciation and death after three weeks. (J42.72.w2)

Incubation

Mortality / Morbidity

• Unknown. This infection has been diagnosed in Lepus americanus - Snowshoe hares found dead or with signs of sickness. (J1.24.w12)

Pathology

• Liver - firm, slight enlargement, fine mottling
• Spleen - slight enlargement and containing multiple white foci
• Lungs - congestion and oedema
• Heart - sero-sanguinous fluid in pericardial sac, epicardial petechiation
• Kidneys - small haemorrhages

SEPTICAEMIA Histopathology:

• Liver -congestion, moderate mononuclear infiltrate around portal vessels, hemosiderin noted between hepatocytes
• Lungs - congestion, oedematous thickening of septae resulting in collapsed air capillaries, mild lymphocyte accumulations in parenchyma associated with dense bacterial clumps

(J1.15.w5)

OCULAR Gross:

• Eyes - hyperaemia of conjunctiva.

OCULAR Histopathology:

• Cutaneous surface of eyelids hyperkeratotis and acanthotic. Necrotic inflammatory cells and cellular debris on surface and in superficial keratin layers.
• Conjunctival surface of eyelids thickened, hyperplastic. Heterophils within epidermis and aggregations of mixed inflammatory cells in dermis . (J1.23.w4).

RESPIRATORY

• Airsacculitis, bronchopneumonia (J1.13.w8)

OVIDUCT

• Salpingitis, sometimes associated peritonitis (J6.24.w1).

• In rabbits with septic arthritis:
  • Soft tissue swelling and inflammation around affected joints. (B614.8.w8)
  • Multiloculated abscesses around the affected joint, with a thin fibrous capsue and fibrous strands internally. (J350.9.w1)
  • Sometimes enlarged associated lymph nodes containing small abscesses. (J350.9.w1)
  • In one individual, a single 3 mm diameter subpleural lesion on the anterior aspect of the lung on the same side as the affected joint. (J350.9.w1)
• Following intravenous inoculation, in one animal: (J42.72.w2)
  • Skeletal
    • Affected knee joint: caseous material in the soft tissues of the joint, with fibrus capsule. Bone and joint surfaces macroscopically normal.
  • Cardiac: 
    • Thickened pericardium, caseous nodules in th parietal layer at the heart base.
    • Pleuro-pericardial adhesion.
    • Empty atria and ventricles, engorged veins.
  • Renal: punctate subcapsular haemorrhages.
  • Pulmonary: congestion, areas of emphysema, scars, adhesions to the pericardium.
  • Liver: congestion, irregular subcapsular yellowing "snail track" lesions.
  • Spleen: atrophic.
  • Lumbar lymph nodes: soft, enlarged.
  • In the intercostal spaces at the roots of the third and fouth ribs, 5 mm diameter caseous nodules.

  (J42.72.w2)

• In three Lepus americanus - Snowshoe hares: (J1.24.w12)
  • Pulmonary: 
    • Plaques, smooth, white, glossy, 1 mm diameter on the lung surface, tracheal mucosa and parietal pleura in one hare. (J1.24.w12)
    • Congestion in one hare. (J1.24.w12)
  • Hepatic: slight hepatomegaly in two of three hares. (J1.24.w12)
  • Spleen: Splenomegally in two hares. (J1.24.w12)
• In a rabbit with septicaemia and gastric stasis syndrome:
  • GIT: Stomach filled with slightly firm ingesta and hair. (J212.17.w2)
  • Pulmonary: lungs contained numerous raised 1-2 mm nodules surrounded by a 2-3 mm zone of congestion and haemorrhage. (J212.17.w2)
  • Tympanic bulla: filled with creamy dry/friable material. (J212.17.w2)

HISTOPATHOLOGY

• In rabbits with septic arthritis:
  • Granulomatous inflammation of affected tissue, with either a follicular structure or colonies of coccobacilli surrounded by rows of "clubs", with chronic inflammatory cells around this and an enclosing fibrous capsule. (J350.9.w1).
  • In the subcutaneous tissue, fibrosis and infiltration of mononuclear cells. (J350.9.w1)
  • In the overlying squamous epithelium, mild hyperplasia. (J350.9.w1)
• In a rabbit with septicaemia and gastric stasis syndrome:
  • Pulmonary: multifocal lesions, alveolar septa and subplueral spaces thickened by haemorrhage, congestion and necrosis. In the alveoli of these areas, blood, fibrin eosinophilic debris. In alveolar capillaries and small arteries, thromi and colonies of small, gram-negative rods in relatively circumscribed aggregates. (J212.17.w2)
  • Kidney, myocardium, liver sinusoids: aggregates of small, gram-negative rods with associated thrombi and occasional necrosis. (J212.17.w2)
• Following intravenous inoculation, in one animal: (J42.72.w2)
  • Skeletal
    • Affected knee joint: masses of inflammatory cells containing areas of amorphous eosinophilic material.
  • Cardiac: 
    • Fibrous thickening. Nodules were bacillary colonies ("dense masses of uncapsulated coccoid cell bodies in a bsophilic matrix" separated from the host reactive cells by amorphous weakly acid-fast eosinophilic material) surrounded by polymorhonuclear leucocytes and mononuclear cells, surrounded by cellular fibrous tissue. 
  • Renal: punctate cortical haemorrhages.
  • Pulmonary: lung congestion, areas of collapse and emphysema.
  • Liver: subcapsular necrotic areas, congested sinusoids.
  • Lumbar lymph nodes: sinuses dilated with lymph stasis.

  (J42.72.w2)

Human Health Considerations

Disease has been reported in either the wild or in captivity in:

Waterfowl

• Mandarin Aix galericulata, wood duck Aix sponsa, long-tailed duck (old-squaw) Clangula hyemalis, Australian shelduck Tadorna tadornoides, mute swan Cygnus olor with ocular or respiratory problems, in a collection in Canada (J1.13.w8).
• Black swan Cygnus atratus with septicaemia in a collection in Canada (J1.15.w5).
• Canada geese Branta canadensis with ocular signs (J1.13.w8, J1.23.w4, B15).
• Domestic ducks and domestic geese with salpingitis in Denmark; also isolated from cloaca/penis of clinically normal ganders (J6.24.w1).
• Duck with septicaemia and goose with airsacculitis (B32.14.w21).

Lagomorphs

• Actinobacillus capsulatus has been recovered from the visceral organs of Lepus americanus - Snowshoe hare. (B614.8.w8)
• Actinobacillus capsulatus is thought to be prevalent in wild lagomorphs. (B614.8.w8)
  • A serological survey found antibodies to Actinobacillus capsulatus in 98/239 (41%) of Lepus americanus - Snowshoe hares from Alaska, USA, and in 51/111 (46%) of those from Alberta, Canada. In Alaska, it was noted that prevalence peaked in May. (J1.26.w13)

Host Species List

• Aix galericulata - Mandarin duck
• Aix sponsa - Wood duck
• Branta canadensis - Canada goose
• Clangula hyemalis - Long-tailed duck
• Cygnus atratus - Black swan
• Cygnus olor - Mute swan
• Tadorna tadornoides - Australian shelduck

Lagomorphs:

• Lepus americanus - Snowshoe hare

Disease has been specifically reported in Free-ranging populations of:

Lagomorphs

• Actinobacillus capsulatus has been recovered from the visceral organs of Lepus americanus - Snowshoe hare. (B614.8.w8)
• Actinobacillus capsulatus is thought to be prevalent in wild lagomorphs. (B614.8.w8)
  • A serological survey found antibodies to Actinobacillus capsulatus in 98/239 (41%) of Lepus americanus - Snowshoe hares from Alaska, USA, and in 51/111 (46%) of those from Alberta, Canada. In Alaska, it was noted that prevalence peaked in May. (J1.26.w13)

Host Species List

• Branta canadensis - Canada goose

Lagomorphs:

• Lepus americanus - Snowshoe hare

General Information on Environmental Factors/Events and Seasonality

• A serological survey found that prevalence of antibodies to Actinobacillus capsulatus in Lepus americanus - Snowshoe hares in Alaska peaked in May, and peaked in the year of highest population density. (J1.26.w13)

Regions / Countries where the Infectious Agent or Disease has been recorded

Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

General Information on Investigation / Diagnosis

• Environmental Assessment
• History & Documentation
• Physical Examination of Mammals
• Necropsy of Mammals
• Imaging in Lagomorph Diagnosis and Treatment
• Clinical Pathology of Lagomorphs
• 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

Similar Diseases (Differential Diagnosis)

Specific Medical Treatment

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General Nursing and Surgical Techniques

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Preventative Measures

WATERFOWL

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Environmental and Population Control Measures

WATERFOWL

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