Infectious Hepatitis in Dogs
Overview
Infectious hepatitis in dogs, also known as Rubarth’s disease, occurs when the pet develops inflammation of the liver caused by adenovirus 1. While this condition can be transmitted to other canids like foxes and wolves, the virus that causes this disease is harmless to humans.
Understanding Infectious Canine Hepatitis
Adenovirus 1 is present in the urine, eyes, and nose discharges of infected animals. Dogs, particularly puppies and unvaccinated canines, can get infected when they come in close contact with these infectious discharges. The incubation period can be as long as 14 days so infected dogs may not exhibit clinical signs of this condition right away. In some cases involving older dogs, the symptoms could be very mild and the infection would go away without further medical intervention.
It’s on the 4th-8th day of infection that the virus will start localizing in the tonsil. It will then spread into the bloodstream, in a condition known as viremia, before it moves to the white blood cells in the liver, and then finally to the hepatic endothelium. The adenovirus will then begin attacking adjacent liver cells. At this stage of the infection, the virus is shed into the dog’s discharges.
Healthy dogs that develop an adequate immune response, the infection will completely clear out after 10-14 days. Those dogs that develop only a partial immune response, the condition could become chronic and could lead to ocular injury due to infection, a condition commonly referred to as “hepatitis blue eyes”.
Signs and Symptoms
In mild cases of infectious canine hepatitis in dogs, clinical symptoms would just include loss of appetite, mild fever, and change of mood. After a week or two, some dogs develop cloudiness in the cornea. The pet may also develop nasal and eye discharges as well as a cough that’s consistent with other upper respiratory tract infections.
If the infection becomes severe, the dog will exhibit symptoms like diarrhea, vomiting, fluid build-up under the skin of its neck and head, and jaundice, a condition where the dog develops a yellowish discoloration in the eyes, gums, or skin due to the pigment bilirubin. Severe infectious hepatitis can be very life-threatening especially for puppies.
Diagnosis
Since the clinical signs of this illness can often be confused with the signs of other canine illnesses like canine parvovirus and distemper, the veterinarian will most likely employ various tests to get to a definite diagnosis.
History and Physical Exam
The vet will ask the pet owner for a thorough medical history of the dog by asking about symptoms and its onset, possible incidents that might have predisposed the dog to this condition, as well as previous illnesses. The vet will also perform a physical exam and check the general appearance of the dog to evaluate reported symptoms.
Blood Work and Urinalysis
The veterinarian will most likely request standard lab works such as a complete blood count (CBC), chemical blood profile, and urinalysis. Laboratory findings will reveal liver function and abnormalities, blood abnormalities like nonregenerative anemia, and coagulation status as these could be symptomatic of liver failure.
Imaging
Imaging tests like radiography and ultrasound allows the vet to have a visual of the abdominal organs and check for abnormalities like fluid buildup in the liver and liver enlargement (hepatomegaly). Ultrasound can provide a more detailed view of the liver so the veterinarian can assess if necrosis (cell death) has taken place.
Biopsy
If chronic infectious hepatitis is suspected, a liver biopsy might be required to obtain a histopathologic diagnosis. This will determine the stage and severity of disease by providing an in-depth look at the extent of inflammation and necrosis.
Treatment
Treatment of infectious hepatitis depends on the severity of the disease. And since this is a viral infection, treatment is mostly focused on staving off the symptoms while waiting for the dog’s immune system to fight off the virus. Some patients can be treated on an outpatient basis while some will have to be admitted so they can have IV therapy to keep them hydrated and restore their electrolyte balance even when they suffer from symptoms like vomiting and diarrhea.
While antibiotics cannot fight off viral infection, the vet will most likely prescribe this to prevent secondary bacterial infection. Immunosuppressive drugs like prednisone and prednisolone are also prescribed to help control the inflammatory process. Furthermore, antifibrotic drugs like colchicine, angiotensin inhibitors, and corticosteroid may also be administered to inhibit liver fibrosis. In severe cases, whole blood or plasma transfusion might be needed to stabilize the dog.
The dog’s diet should also be modified to make sure that nutritional requirements are met to facilitate faster tissue repair and regeneration. Animals suffering from this condition will have to be given frequent small meals if they can tolerate it. This is supplemented with partial intravenous nutrition for up to five days. If the dog keeps on vomiting and can’t tolerate it, total intravenous nutrition will be necessary.
Prevention
The best way to prevent this disease is to vaccinate puppies at 6-8 weeks of age. This is usually part of the routine vaccination program so the prevalence of this disease is kept at a minimum. Protection from the vaccine will wear off with time; thus, pet owners will have to talk with the veterinarian to schedule booster revaccination.
It’s best to separate the infected dog from other dogs. And even if the dog has recovered, it may still shed the virus in its urine and other discharges for up to one year. To disinfect a dog’s living quarters, quaternary ammonium compounds and steam cleaning are very effective in eliminating the virus.
Prognosis
Early diagnosis and intervention go a long way in improving the outlook of the dog with infectious hepatitis. Dogs that already have decompensated liver function and severe symptoms like hypoglycemia, bridging fibrosis, and prolonged clotting time have a poorer prognosis than those that exhibit milder symptoms.
Even with the right treatment, there is always the possibility of recurrence. However, timely intervention and proper living management could provide the dog with a life free from the clinical signs of this illness for years to come.
Veterinary care for canine hepatitis and other health conditions can cost thousands of dollars pet health insurance helps pay for medical treatment when your dog gets sick or injured.
Sources:
- https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/infectious-canine-hepatitis
- https://www.merckvetmanual.com/generalized-conditions/infectious-canine-hepatitis/overview-of-infectious-canine-hepatitis
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