Infectious canine hepatitis
Encyclopedia
Infectious canine hepatitis is an acute liver infection in dogs caused by canine adenovirus
type-1 (CAV-1). CAV-1 also causes disease in wolves
, coyote
s, and bear
s, and encephalitis
in fox
es. The virus
is spread in the feces, urine, blood, saliva, and nasal discharge of infected dogs. It is contracted through the mouth or nose, where it replicates in the tonsil
s. The virus then infects the liver
and kidney
s. The incubation period
is 4 to 7 days.
Symptoms include fever
, depression, loss of appetite, coughing, and a tender abdomen. Cornea
l edema
and signs of liver disease, such as jaundice
, vomiting, and hepatic encephalopathy
, may also occur. Severe cases will develop bleeding
disorders, which can cause hematoma
s to form in the mouth. Death can occur secondary to this or the liver disease. However, most dogs recover after a brief illness, although chronic corneal edema and kidney lesions may persist.
Diagnosis is made by recognizing the combination of symptoms and abnormal blood tests that occur in infectious canine hepatitis. A rising antibody titer
to CAV-1 is also seen. The disease can be confused with canine parvovirus
because both will cause a low white blood cell
count and bloody diarrhea in young, unvaccinated dogs.
Treatment is for the symptoms. Most dogs recover spontaneously without treatment. Prevention is through vaccination
(ATCvet code and various combination vaccines). Most combination vaccine
s for dogs contain a modified canine adenovirus type-2. CAV-2 is one of the causes of respiratory infections in dogs, but it is similar enough to CAV-1 that vaccine for one creates immunity
for both. CAV-2 vaccine is much less likely to cause side effects than CAV-1 vaccine. One study has shown the vaccine to have a duration of immunity of at least four years.
CAV-1 is destroyed in the environment by steam cleaning and quaternary ammonium compound
s. Otherwise, the virus can survive in the environment for months in the right conditions. It can also be released in the urine of a recovered dog for up to a year.
Adenoviridae
Adenoviruses are medium-sized , nonenveloped icosahedral viruses composed of a nucleocapsid and a double-stranded linear DNA genome...
type-1 (CAV-1). CAV-1 also causes disease in wolves
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...
, coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s, and bear
Bear
Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...
s, and encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
in fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es. The virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
is spread in the feces, urine, blood, saliva, and nasal discharge of infected dogs. It is contracted through the mouth or nose, where it replicates in the tonsil
Tonsil
Palatine tonsils, occasionally called the faucial tonsils, are the tonsils that can be seen on the left and right sides at the back of the throat....
s. The virus then infects the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
and kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s. The incubation period
Incubation period
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical or radiation, and when symptoms and signs are first apparent...
is 4 to 7 days.
Symptoms include fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, depression, loss of appetite, coughing, and a tender abdomen. Cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
l edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
and signs of liver disease, such as jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
, vomiting, and hepatic encephalopathy
Hepatic encephalopathy
Hepatic encephalopathy is the occurrence of confusion, altered level of consciousness and coma as a result of liver failure. In the advanced stages it is called hepatic coma or coma hepaticum...
, may also occur. Severe cases will develop bleeding
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
disorders, which can cause hematoma
Hematoma
A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...
s to form in the mouth. Death can occur secondary to this or the liver disease. However, most dogs recover after a brief illness, although chronic corneal edema and kidney lesions may persist.
Diagnosis is made by recognizing the combination of symptoms and abnormal blood tests that occur in infectious canine hepatitis. A rising antibody titer
Serology
Serology is the scientific study of blood serum and other bodily fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum...
to CAV-1 is also seen. The disease can be confused with canine parvovirus
Canine parvovirus
Canine parvovirus type 2 is a contagious virus mainly affecting dogs. The disease is highly contagious and is spread from dog to dog by direct or indirect contact with their feces. It can be especially severe in puppies that are not protected by maternal antibodies or vaccination. It has two...
because both will cause a low white blood cell
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
count and bloody diarrhea in young, unvaccinated dogs.
Treatment is for the symptoms. Most dogs recover spontaneously without treatment. Prevention is through vaccination
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
(ATCvet code and various combination vaccines). Most combination vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s for dogs contain a modified canine adenovirus type-2. CAV-2 is one of the causes of respiratory infections in dogs, but it is similar enough to CAV-1 that vaccine for one creates immunity
Immunity (medical)
Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...
for both. CAV-2 vaccine is much less likely to cause side effects than CAV-1 vaccine. One study has shown the vaccine to have a duration of immunity of at least four years.
CAV-1 is destroyed in the environment by steam cleaning and quaternary ammonium compound
Quaternary ammonium cation
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+, R being an alkyl group or an aryl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged,...
s. Otherwise, the virus can survive in the environment for months in the right conditions. It can also be released in the urine of a recovered dog for up to a year.