Infectious Canine Hepatitis (with special reference to Bears)

Summary Information
Diseases / List of Viral Diseases / Disease description:

This disease page is currently predominantly used in Wildpro to link different data types and demonstrate inter-relationships. Whilst basic information is available, It does not contain detailed information.

Alternative Names
  • ICH
  • Canine adenovirus 1 infection
  • CAV 1 infection
  • Hepatitis contagiosa canis
  • Rubarth's disease
  • Fox encephalitis
  • Encephalitis infectiosa vulpis
Disease Agents Canine adenovirus 1 (CAV 1) (B101)
Infectious Agent(s)
Non-infectious Agent(s) --
Physical Agent(s) -- Indirect / Secondary
General Description In dogs and skunks, hepatitis; in foxes, encephalitis (B58.15.w15)

Variable: slight fever and mucous membrane congestion to severe depression, marked leucopaenia, increased bleeding time.

  • Elevated temperature, usually biphasic, over 104F/40C
  • Tachycardia, leucopaenia
  • Apathy, anorexia, thirst, conjunctivitis, serous oculonasal discharge, occasionally signs of abdominal pain.
  • May also see:
  • hyperaemia/petechiation of oral mucous membranes
  • vomiting
  • subcutaneous oedema (head, neck, trunk)
  • Corneal opacity, usually transient (may be only sign noted in mild cases)
  • May be later chronic hepatitis (seen in dogs with low levels of passive antibodies at time of exposure)
In foxes:
  • Sudden onset, rapid course
  • May die without obvious clinical signs, or within few hours.
  • Anorexia (may be only sign)
  • Diarrhoea (mucus-streaked, sometimes bloody), depression
  • Rhinitis, slight watery ocular discharge (sometimes interstitial keratitis in non-fatal cases)
  • Nervous signs (may be first/major sign): hyperexcitability, convulsions (may be myotonic and myoclonic), with periods of lethargy in between; sometimes paralysis of one or more limbs
  • Death in few hours to few days.

(B58.15.w15, B101)

In bears:

Clinical signs:

  • Ataxia (J1.19.w7)
  • Excessive salivation. (J1.19.w7)
  • Vomiting. (J1.19.w7)
  • Diarrhoea. (J4.185.w3)
  • Lethargy. (B336.51.w51, J3.139.w5, J4.185.w3)
  • Signs of abdominal pain, such adopting the foetal position. (J4.185.w3)
  • Paddling of the legs. (J1.19.w7)
  • Nystagmus. (J1.19.w7, J4.185.w3)
  • Hind limb ataxia.(B336.51.w51, J1.19.w7, J3.139.w5, J4.185.w3)
  • Seizures. (B336.51.w51, J1.19.w7, J4.185.w3)
  • Paralysis. (B336.51.w51, J4.185.w3)
  • In two 3.5-month-old Ursus americanus - American black bear cubs: ataxia, excess salivation, vomiting, convulsions, paddling of the legs, and periodic nystagmus. Death within 24 days in one cub; the other was euthanased in extremis four days later. (J1.19.w7)
  • Anorexia. (B336.51.w51, J1.19.w7, J3.139.w5, J4.185.w3)
  • Death within 12 hours of the firsts clinical signs. (B336.51.w51, J4.185.w3)
  • The surviving bears from an epizootic showed neurological signs and  lethargy for 60 to 90 days. (B336.51.w51, J4.185.w3)
  • In two of the surviving bears from an epizootic a unilateral corneal opacity was detected 10 to 14 days after the onset of the clinical signs. The corneal opacity regressed over the next weeks without treatment. ( J4.185.w3)

Gross pathology:

  • Generalised icterus. (J3.139.w5)
  • Heart: Petechial haemorrhages in the epicardium. (J3.139.w5, J4.185.w3)
  • Thymus: Petechial haemorrhages. (J4.185.w3)
  • Abdominal cavity: 40-50 ml of clear fluid. (J1.19.w7)
  • Gastrointestinal tract:
    • The stomach and small intestine contained a large volume of haemorrhagic fluid. (J3.139.w5)
    • The gastric mucosa was roughened. (J3.139.w5)
    • Hyperemia of the gastric mucosa. (J4.185.w3)
  • Liver: Small with sharp edges, yellow colour and hard consistency. (J3.139.w5)
  • Gall bladder: Thickened due to haemorhagic oedema and mucosa was congested. (J3.139.w5)
  • Lymph nodes: 
    • Enlarged and pale mesenteric lymph nodes. (J1.19.w7)
    • Petechial haemorrhages. (J4.185.w3)
  • Spleen: Congestion. (J1.19.w7)
  • Urinary bladder: Petechial haemorrhages. (J4.185.w3)
  • Skeletal muscle: Petechial haemorrhages. (J4.185.w3)


  • CNS: 
    • Meninges, vascular walls, perivascular areas and adjacent neuropil showed a mild infiltrate of neutrophils. (J1.19.w7)
    • Throughout the brain, minute haemorrhages. (J1.19.w7)
    • Within the brain stem, a single focus of gliosis . (J1.19.w7)
    • Within the vessels of the neuropil and meninges, epithelial cells were hypertrophied; many contained intranuclear inclusion bodies. (J1.19.w7)
    • Capillary endothelial cells in the brain contained intranuclear inclusion bodies. (J4.185.w3)
  • Heart: Capillary endothelial cells in the myocardium contained intranuclear inclusion bodies. (J4.185.w3)
  • Gastrointestinal tract: Capillary endothelial cells in the stomach contained intranuclear inclusion bodies. (J4.185.w3)
  • Liver: 
    • Mild multifocal degeneration and necrosis of hepatocytes. (J1.19.w7, J4.185.w3)
    • Centrilobular hepatocellular degeneration and necrosis. (J3.139.w5)
    • Basophilic intranuclear inclusion bodies were found in hepatocytes. (J1.19.w7, J3.139.w5, J4.185.w3)
    • Mixture of inflammatory infiltration, specially lymphocytes. (J4.185.w3)
  • Gall bladder:
    • The wall showed extensive haemorrhage of the mucosa, tunica muscularis and serosa. (J3.139.w5)
    • Thickening of the wall due to haemorrhage and oedema. (J3.139.w5)
  • Spleen: Reticuloendothelial cell hyperplasia. (J1.19.w7)
  • Kidney: 
    • Basophilic intranuclear inclusion bodies were found in renal glomerular endothelial cells. (J1.19.w7, J4.185.w3)
    • Capillary endothelial cells in the kidney contained intranuclear inclusion bodies. (J4.185.w3)
  • Bladder: In the vascular endothelium of the submucosa of the urinary bladder, numerous intranuclear inclusion bodies. (J1.19.w7)

Morbility/ Mortality:

  • In one epizootic, 28 out of 148 bears were affected by the disease and 24 of 28 affected bears died. (B336.51.w51, J4.185.w3)
Further Information Infection from urine, faeces, saliva, probably via the oropharynx. The virus may be shed in urine for six months or more following recovery (B58.15.w15, B101)
In Bears:


  • Clinical signs and pathological lesions consistent with infectious canine hepatitis. (J1.19.w7)
  • Virus isolation. (J1.19.w7, J4.185.w3)
  • Virus identification by fluorescent antibody and/or serum-virus neutralisation (J1.19.w7, J4.185.w3)
  • Virus neutralisation test for antibody to CAV-1. (J4.185.w3)
  • Identification of adenovirus particles by electron microscopy. (J1.19.w7, J4.185.w3)


  • Euthanasia. (J1.19.w7)


  • Killed vaccines are suggested for use in bears kept in zoos and exhibitions. (J1.19.w7, J4.185.w3)
  • Note: Bears have been reported to be infected with canine adenovirus type 1 after been vaccinated with live MLV vaccines. Therefore the use of live vaccines is not recommended. (B10.48.w43)
  • See: Preventative Medicine for Mammals - Vaccination Protocols

Occurrence in Bears

Antibodies reported in bears

Techniques linked to this disease
Host taxa groups /species Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are linked below:

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

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