Canine contagious hepatitis
The infectious canine hepatitis ( Hcc ; Syn: "Infectious hepatitis of dogs," Rubarth's disease , fox encephalitis , infectious canine hepatitis (ICH) ) is through a virus -induced liver inflammation of dogs . Overall, as a result of effective and comprehensive vaccination measures, the disease is rarely observed today.
Epizootiology
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The Hcc pathogen, canine adenovirus 1 (CAV-1 or CAdV-1) from the species Canine Mastadenovirus A (CadV-A), belongs to the genus Mastadenovirus in the virus family Adenoviridae . The Hcc occurs worldwide and besides most dogs it can also attack skunks , raccoons and some bear species , whereby domestic dogs have the highest susceptibility overall.
In the acute phase of the disease, the virus is excreted in saliva , feces , nasal secretions and urine . After healing or in the case of latent virus carriers, the urine in particular plays a role in the transmission of pathogens. Transmission from the mother to the fetus via the placenta has also been proven. Most of the time, the infection occurs through contact of unprotected animals with excretions from clinically inapparent infected animals. Since the pathogen is quite stable, it can remain infectious outside the living organism for several weeks at room temperature, and even up to 9 months at temperatures below 4 ° C. The germs get into the host mainly orally, i.e. via the mouth, whereby the virus first multiplies in the tonsils and then spreads via lymph vessels and lymph nodes into the blood . This viremic phase lasts about 4 to 8 days. As a result, especially liver cells (are hepatocytes ), the inner lining ( endothelium ) of blood vessels , the endothelium of renal and cornea ( cornea ) and medium-sized eyeball ( uvea ) affected.
The incubation period is 2–5 days.
The virus variant Canine Adenovirus-2 (CadV-2) also belongs to the species Canines Mastadenovirus A (CAdV-A)
Symptoms
The symptoms vary greatly depending on the form. In general, it can be said that the more acute the disease, the less favorable the prognosis .
Peracute course
In the peracute course, the animals die within a few hours. The only symptom is usually the finest bleeding ( petechiae ) as a result of a coagulation disorder ( DIC ).
Acute course
The acute course also begins with a high fever , apathy , vomiting and reluctance to eat. The tonsils, lymph nodes , spleen, and liver are swollen. Due to the vascular inflammation, edema and bleeding (petechiae, ecchymosis ) of the mucous membranes, as well as in the body cavities and the anterior chamber of the eye, appear. Are occasionally bleeding into the central nervous system and neurological symptoms observed. In addition, kidney damage can occur due to the deposition of immune complexes in the kidney corpuscles , which are manifested by the appearance of protein in the urine ( proteinuria ). The occasional clouding of the cornea ( blue eye syndrome , see below) has the same cause .
Liver palpation is generally painful.
Subacute course
The subacute course begins like the acute one, only the symptoms are less pronounced. Fever, diarrhea, vomiting and uveitis dominate here . After 1–3 weeks, the cornea becomes bluish due to edema and the deposition of immune complexes ( blue eye syndrome ), which usually heals spontaneously 1 to 2 weeks later.
Chronic course
In the chronic course there are only minor symptoms. It is therefore rarely recognized. Here, the organism is unable to eliminate the virus, so that permanent colonization (persistence) of the liver occurs and thus chronic hepatitis , which leads to liver fibrosis and liver cirrhosis .
Diagnosis, differential diagnosis
In addition to the symptoms already described above, affected animals often show a lack of blood platelets ( thrombocytopenia ) and an increase in the activity of liver enzymes . The blood clotting time can be significantly increased as a result of consumption coagulopathy. Many patients excrete proteins and bilirubin in the urine. A final diagnosis can be made by isolating viral material from nasal secretions, blood or urine or by means of a histological examination of a liver biopsy .
Distemper , parvovirus , leptospirosis and bacterial tonsillitis or tonsillitis caused by other viruses are the main differential diagnoses. The bleeding from the mucous membranes and sudden deaths can be reminiscent of poisoning with anticoagulant substances.
therapy
A causal therapy is not possible. A treatment attempt can be made by administering specific immunoglobulins or interferon , but the effect of this has not been proven. In addition, supportive measures in the sense of symptomatic therapy are useful.
prophylaxis
Combination vaccines are usually used for prophylaxis, which in addition to Hcc also immunize against distemper, parvovirus , leptospirosis and rabies and are offered by a wide variety of manufacturers (e.g. Versican DHPPi L3 R , Epivax SHPPi + LT , Eurican SHPLT , Nobivac SHP + LT , Quantum DAPPi / CVL , Virbagen canis SHPPiLT ). The use of live vaccines can cause the appearance of the blue eye syndrome. It is therefore more favorable to use inactivated vaccines or heterologously attenuated CAV-2 live vaccines, which avoid this effect.
literature
- Michael Rolle, Anton Mayr, Mathias Büttner: Medical microbiology, infection and disease theory . Georg Thieme Verlag, 8th edition 2007, pp. 194–195. ISBN 978-3-8304-1060-7
- Katrin Hartmann and Peter F. Suter: Virus infections. In: Peter F. Suter and Hans G. Nobody (eds.): Internship at the dog clinic. Paul-Parey-Verlag, 10th edition 2006, pp. 282-283, ISBN 3-8304-4141-X
Individual evidence
- ↑ Uwe Truyen and Marian C. Horzinek: Vaccination management for dogs: non-core components (HCC, kennel cough, borreliosis, canine herpes virus and canine coronavirus). Kleintierpraxis 52 (2007), pp. 579-588.
- ↑ a b c d e ICTV: ICTV Taxonomy history: Human mastadenovirus C , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
- ↑ ViralZone: ICTV 2016 Master Species List # 31 with Acronyms, (Excel XLSX) , SIB Swiss Institute of Bioinformatics
