Canine adenovirus (CAV)

Canine adenovirus (CAV) is a non-enveloped, double-stranded DNA virus belonging to the family Adenoviridae and the genus Mastadenovirus [2, 9]. It is classified into two distinct serotypes: CAV-1, the causative agent of infectious canine hepatitis (ICH), and CAV-2, which primarily causes infectious tracheobronchitis, a component of the kennel cough complex [8, 12]. CAV-1 has a broad tissue tropism, targeting the liver, kidneys, and vascular endothelium, and can cause severe systemic disease characterized by fever, abdominal pain, and "blue eye" (corneal opacity) [13, 15]. CAV-2 is restricted to the respiratory tract and is generally less virulent, making it the preferred component for modified-live vaccines that provide cross-protection against both serotypes [12, 17]. Beyond its role as a pathogen, CAV-2 is extensively researched as a viral vector for gene therapy due to its ability to undergo retrograde axonal transport in neurons and the relative lack of pre-existing immunity in humans compared to human adenoviral vectors [1, 3, 11]. The virus enters host cells by binding to the coxsackievirus and adenovirus receptor (CAR) and utilizing integrins for internalization [14, 18]. Therapeutic management is primarily preventive through vaccination, as specific antiviral treatments are rarely employed in clinical veterinary practice [9, 13]. In research settings, antivirals like cidofovir may be used to inhibit viral DNA polymerase and prevent replication [9]. Safety concerns associated with the virus include the risk of post-vaccinal complications and the potential for recombination in vector-based applications [1, 17].

Other names

CAdVCanine mastadenovirus ACanine adenovirus type 1Canine adenovirus type 2Infectious canine hepatitis virusCanine laryngotracheitis virus

Vaccines containing modified-live canine adenovirus type 2 (CAV-2) induce a protective immune response, including the production of neutralizing antibodies and cell-mediated immunity, which provides cross-protection against both CAV-1 and CAV-2 [12, 17]. Antiviral agents such as cidofovir function as nucleoside analogs that competitively inhibit viral DNA polymerase, thereby preventing viral genome replication [9].