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I created this blog as an instrument of what I have encountered in the world of veterinary medicine as a proud vet student. Comments and suggestions are welcome here at;

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Regards,
Aina Meducci 2012

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The following blog posts is not genuinely from my research but through readings and citation from trusted website. I do not own any of the copyright and therefore you may use it at your own risk

SINCE I AM NOT A VETERINARIAN YET, THEREFORE I CAN'T CONSULT ANY MEDICAL ADVICE TO YOU AND YOUR PETS! EXTREMELY IMPORTANT!.

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Infectious Canine Hepatitis

I remember during my 2nd year where we had virology oral exam with Dr J. So before waiting our names to be called in, we were scampering for notes and memorized the all the virus and the diseases associated with it like nobody business. Until my name was called, I went and sat in front of the examiner. I was doing quite well for the rest of the exam until he came out with the final question;


"Name the virus that causes infectious canine hepatitis?"


Opps...I blown the day :(


At the end of the semester, virology is my favorite subject


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Canine infectious hepatitis

Infectious canine hepatitis an acute highly contagious viral disease of dogs which affect the liver and other organs and is characterized by high rise of temperature, diarrhoea, vomiting and convulsion. Dogs of all ages, specially puppies and foxes is affected by this disease. A carrier dog may recover, but continue to spread the virus via its urine for up to six months.Severely affected dogs will have a fever, loss of appetite, depression, diarrhoea, tonsillitis and acute abdominal pain due to an inflamed liver. Death may result within 36 hours. Corneal opacity known as "blue eye" may follow infection.



Abdominal pain in a dog with ICH


Aetilogy and transmission

ICH is caused by a nonenveloped DNA virus, canine adenovirus 1 (CAV-1), which is antigenically related only to CAV-2 (one of the causes of infectious canine tracheobronchitis). CAV-1 is resistant to lipid solvents and survives outside the host for weeks or months, but a 1-3% solution of sodium hypochlorite (household bleach) is an effective disinfectant.


Ingestion of urine, feces, or saliva of infected dogs is the main route of infection. Recovered dogs shed virus in their urine for ≥6 mo. Initial infection occurs in the tonsillar crypts and Peyer’s patches, followed by viremia and infection of endothelial cells in many tissues. Liver, kidneys, spleen, and lungs are the main target organs. Chronic kidney lesions and corneal clouding (“blue eye”) result from immune-complex reactions after recovery from acute or subclinical disease.


Even a dog dish that has been licked clean can carry the virus. The tonsils and lymph nodes are the first body parts effected. The incubation period can last 4-9 days, after which the virus enters the bloodstream.



dog eye diseases photo

Blue eye dog infectious hepatitis



Pathogenesis

The virus can remain in the kidneys of dogs that have recovered from infection for up to one year, making it all the more difficult to determine what locations might be contaminated. The particles enter the body through the nose or mouth and initially infect the tonsils. Here the virus replicates and proceeds to invade the nearby lymph nodes.This process of replication continues for 4 to 8 days, at which point the virus spreads from the lymphatic system and enters the bloodstream.

Once in the blood, CAV-1 particles infect a varieyt of other target organs – the liver, kidneys, and eyes. The viral particles themselves are cytotoxic which is why they are capable of doing so much damage. The liver is almost always the most severely affected organ, with consequences including disturbance of protein and fat manufacture, problems with bile secretion, and difficulty detoxifying drugs, chemicals, and bacteria from food. ICH is generally not fatal, but when it is, death is usually a result of massive hemorrhage, fluid leakage from a severely damaged liver, and central nervous system trauma which triggers seizure and coma.


INFECTIOUS CANINE HEPATITIS IS NOT ZOONOTIC!



Clinical signs

Signs vary from a slight fever to death. The mortality rate is highest in very young dog. The first sign is a fever of >104°F (40°C), which lasts 1-6 days and is usually biphasic (fever associated with 2 different sets of symptoms as it progress) . If the fever is of short duration, leukopenia may be the only other sign, but if it persists for >1 day, acute illness develops. Tachycardia out of proportion to the fever may occur.

On the day after the initial temperature rise, leukopenia develops and persists throughout the febrile period. The degree of leukopenia varies and seems to be correlated with the severity of illness. Signs are anorexia, thirst, conjunctivitis, serous discharge from the eyes and nose, and occasionally abdominal pain and vomiting. Intense hyperemia or petechiae of the oral mucosa, as well as enlarged tonsils, may be seen. There may be subcutaneous edema of the head, neck, and trunk.

Clotting time is directly correlated with the severity of illness. It may be difficult to control hemorrhage, which is manifest by bleeding around deciduous teeth and by spontaneous hematomas, because of underlying disseminated intravascular coagulation. Although CNS involvement is unusual, severely infected dogs may develop convulsions from forebrain damage; brain stem hemorrhages, resulting in paresis, are common.

The fatal form of the disease results in a sudden onset of severe symptoms. Bleeding from the nose and gums, enlarged abdomen due to fluid leaking from the liver, bloody diarrhea and vomit, seizures due to central nervous system association, disorientation, coma, and death may occur. Pets may die suddenly without any obvious illness. Infectious Canine Hepatitis is most severe and the mortality rate is highest in young dogs. Veterinary attention will need to be sought ASAP.


Lesions

Endothelial damage results in “paint brush” hemorrhages on the gastric serosa, lymph nodes, thymus, pancreas, and subcutaneous tissues. Hepatic cell necrosis produces a variegated color change in the liver, which may be normal in size or swollen. The gallbladder wall may be edematous and thickened; edema of the thymus may be found. Grayish white foci may be seen in the kidney cortex.


Diagnosis

Urinalysis and blood tests may be performed in an attempt to detect viral antibodies. Similarly, viral antibodies can be detected using immunofluorescent techniques. In addition, the ELISA test may be used to look for the presence of viral particles in the feces of a sick animal.


Treatment and management

There is no specific treatment for infectious canine hepatitis so treatment is aimed at managing the symptoms until the virus runs its course. Depending on the severity of illness, hospitalization and intravenous fluid therapy may be necessary. Antibiotics don't treat the virus but may be prescribed to ward off secondary bacterial infections. In severe cases, blood transfusions may be necessary

Management for ICH;

(a) Broad spectrum antibiotic -To prevent secondary bacterial infection
(b) Anti emetic - To stop vomiting
(c) Anti diarrhoea- To stop diarrhoea
(d) Anti serum may be tried
(e) Blood transfusion in case of severely infected dog. Dose is 5-8ml/lb of body weight by slow
intra venous infusion
(f) Fluid theraphy - NSS or DNS to restore fluid and electrolyte loss
(g) Anti pyretic – In case of high rise of temperature
(h)Vitamins therapy and protein hydrolysate- To restore vitality
(i) Care nursing of infected dogs


Prevention

  • Vaccination is the most recommended method of preventing Infectious Canine Hepatitis. While it seems logical to vaccinate using the CAV-1 virus, this can usually cause unwanted side effects such as the bluing of the eye and the shedding of virus. Vaccination with a very closely related virus, CAV-2, is much safer, and will help the dog build immunity against CAV-1. CAV-2 is also thought to play a part in a common condition called kennel cough, so vaccinating with CAV-2 would result in immunity to both conditions.



It is important that all puppies commence a vaccination program from 6-8 weeks of age and that all adult dogs have their boosters.

  • Unvaccinated dog should be kept away from public places, dogs outside household, or dirty food bowls that are left outside or belonging to dogs outside household. Keep an eye on the dog during walks to ensure he does not consume urine or feces.
  • Disinfection of contaminated areas with a bleach or iodine solution can kill the virus


Sources: Merks Veterinary Manual, animalhealthcareveterinary.blogspot, ICF; Cornell university college of veterinary medicine, ICF; petsmd.com, Dog eye diseases; dog-health-handbook.com .



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