Adenoviruses are non-enveloped double-stranded DNA viruses, which are characterised by a high tenacity. They belong to the linear double-stranded DNA viruses. Adenoviruses are strictly host-specific and only in exceptional cases infection of related or unrelated animal species occurs. Adenoviruses mostly cause mild respiratory symptoms and are involved in many multifactorial disorders.
Hepatitis contagiosa canis (HCC)
HCC is caused by canine adenovirus 1 (CAV-1). The virus is shed in urine and faeces and transmission occurs directly or indirectly. After oronasal infection, the virus first multiplies in the tonsils and subsequently in the endothelium of the blood vessels, in hepatocytes as well as in cornea and uvea. Deposition of immune complexes can result in glomerulonephritis and uveitis with a corneal oedema (“blue eye”). HCC can be acute or chronic. Especially in unvaccinated puppies, HCC can take a peracute or acute course and can be fatal. Not only dogs, but also all other species of the family Canidae are susceptible to an infection with CAV-1.
As consistent vaccination against HCC has been carried out in Germany for some time now, the virus CAV-1 has largely disappeared from dog populations. However, CAV-1 still occurs in Eastern European countries.
Infectious laryngotracheitis is caused by canine adenovirus 2 (CAV-2). The virus has a strong affinity to the epithelia of the respiratory tract and is a component of the “kennel cough complex”.
Adenoviruses, which have mostly been documented in lizards and snakes, play an important role in reptiles. Literature particularly describes adenoviruses in bearded dragons (Pogona). The clinical picture is often non-specific. In Pogona, mainly young animals are affected. Clinical signs which are often seen are anorexia, apathy, diarrhoea and opisthotonus. Boas, colubrids and vipers belong to the snake families that are often affected. Gastrointestinal symptoms are very typical. The liver, too, is very frequently affected. Transmission probably occurs through the faeces, but also a vertical transmission is being discussed.