Infectious Canine Hepatitis

Also known as:

Rubarth's Disease Canine adenovirus infection

Description

• adenovirus - Canine Adenovirus 1
• acute and generalised infection
• highly infectious
• spread via the urine of infected animals over a long period of time

Signalment

• young dogs

Diagnosis

• Intranuclear inclusion bodies in hepatocytes can be seen under H&E staining
• Vascular endothelium can be stained for viral antigen by immunofluorescence

Clinical Signs

• recovering animals may show an immune-mediated uveitis with corneal opacity

Pathology

Pathogenesis

Canine adenovirus 1 (CAV1) initially infects and replicates in the cells of the oropharynx, before establishing a viraemia. A tropism for endothelial cells exists, leading to attack of the liver sinusoids and the lining of the gall bladder. Kuppfer cells are also affected. This results in hepatitis. In foxes, the virus replicates in the endothelial cells of the brain resulting in neuronal damage, fits, and paralysis.

Gross

• the virus has a tropism for endothelium and hepatocytes
  • widespread haemorrhages, especially on serosal surface
• distinctly pale mottled appearance
  • from extensive necrosis, characteristically periacinar (centrilobular) in distribution - the reason for the increased susceptibility of this area is not known
• enlarged
• friable
• fibrinous or fibrino-haemorrhagic strands between lobes
• gall bladder
  • wall usually shows oedema (up to 2cm diameter)
• lymph nodes and tonsils are enlarged and reddened, sometimes haemorrhagic
• Post Mortem: swollen, hemorrhagic liver, ascites, and oedema of the gall bladder
• In older dogs, may present more mildly with lymph node enlargement and chronic interstitial nephritis

Microscopically

• basophilic intranuclear inclusion bodies
  • in hepatocytes and macrophages

Treatment

Control

In an outbreak

• Isolate infected dogs
• Disinfect premises

To prevent

• Vaccination: tissue culture adaptation that may be live or inactivated
• Cross protection with CAV2
• Live vaccines are known to cause keratitis in Afghans, Red Setters and Saluki