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==Introduction==
==Classification==
Canine adenovirus 1 (CAV1) is a member of the Adenoviridae family. The Adenoviridae are a family of double-stranded DNA viruses which have an icosahedral nucleocapsid and have been isolated from many mammals and birds. However, only a small number of Adenoviridae cause significant veterinary disease, one of these being canine adenovirus 1.
Classification
Classification
This family originally consisted of only two genera, Mastadenovirus, which infect mammals, and Aviadenovirus, which infect birds. There are also several as yet unassigned and recently assigned viruses in the family.
This family originally consisted of only two genera, Mastadenovirus, which infect mammals, and Aviadenovirus, which infect birds. There are also several as yet unassigned and recently assigned viruses in the family.
Mastadenovirus
Mastadenovirus
This genus consists of 20 virus species that infect mammals including canine, equine, bovine, ovine and porcine adenoviruses. All 20 species share a common antigen. Important diseases are infectious canine hepatitis, canine adenovirus 2 infection, and equine adenovirus A infection.
This genus consists of 20 virus species that infect mammals including canine, equine, bovine, ovine and porcine adenoviruses. All 20 species share a common antigen. Important diseases are infectious canine hepatitis, canine adenovirus 2 infection, and equine adenovirus A infection.
Aviadenovirus
Aviadenovirus
This genus includes the viruses of inclusion body hepatitis, quail bronchitis, marble spleen disease and a number of adenoviruses of poultry and birds that are not associated with significant diseases. Members of the genus share a common antigen.
This genus includes the viruses of inclusion body hepatitis, quail bronchitis, marble spleen disease and a number of adenoviruses of poultry and birds that are not associated with significant diseases. Members of the genus share a common antigen.
Previously Unassigned Adenoviruses
Previously Unassigned Adenoviruses
Included in this category are the viruses that have recently (2002) been placed in the genera Atadenovirus and Siadenovirus. These viruses include the egg drop syndrome virus (Atadenovirus), turkey hemorrhagic enteritis (Siadenovirus), adenoviral splenomegaly of chickens (Atadenovirus) and ovine adenovirus 287 (Atadenovirus; of research interest, but of no disease significance) and some bovine adenovirus types 4 to 8 (Atadenovirus).
Included in this category are the viruses that have recently (2002) been placed in the genera Atadenovirus and Siadenovirus. These viruses include the egg drop syndrome virus (Atadenovirus), turkey hemorrhagic enteritis (Siadenovirus), adenoviral splenomegaly of chickens (Atadenovirus) and ovine adenovirus 287 (Atadenovirus; of research interest, but of no disease significance) and some bovine adenovirus types 4 to 8 (Atadenovirus).
MastadenovirusInfectious Canine HepatitisCause
MastadenovirusInfectious Canine HepatitisCause
Canine adenovirus 1. The DNA sequence of this virus has been determined.
Canine adenovirus 1. The DNA sequence of this virus has been determined.
==Viral Characteristics==
Non-enveloped, viruses with icosahedral symmetry containing a single, linear molecule of double-stranded DNA.
The capsid consists of capsomeres (called hexons) and 12 vertex capsomeres (called pentons). These are the only viruses with a fiber (the fiber antigen) protruding from each of the 12 pentons (see Fig. 13-1).
The fiber is the structure of attachment to host cells and is also a type specific hemagglutinin.
The hexon of mammalian adenoviruses contains a cross-reacting group antigen.
The fiber antigen attaches to a specific cell receptor and initiates replication.
The dsDNA encodes approximately 30 proteins. Viral DNA replication, mRNA transcription and virion assembly occur in the nucleus, utilizing both host and virus-encoded factors. This results in the formation of basophilic and / or acidophilic intranuclear inclusions.
Many adenoviruses agglutinate red cells of various animal species and some are capable of malignant transformation in tissue culture cell and oncogenesis when inoculated into laboratory animals.
They are resistant to trypsin and lipid solvents, and moderately resistant on premises.
Figure 13-1. Adenoviridae (70 - 90 nm). Note the fiber proteins protruding from the vertices of the 12 pentons. To view click on figure
==Transmission and Epidemiology==
==Disease==
his family consists of double-stranded DNA viruses with an icosahedral nucleocapsid. They have been recovered from many mammalian and avian species. Many are found in the respiratory tract and infections are often persistent. Only a small number cause significant veterinary diseases.
Viral Characteristics
Occurrence
Occurrence
Dogs younger than one year of age are most often affected. The virus also infects wild and captive foxes causing encephalitis, and wolves, coyotes and bears. Other carnivores may sustain subclinical infections. The disease occurs commonly worldwide, but is uncommon where vaccination is practiced.
Dogs younger than one year of age are most often affected. The virus also infects wild and captive foxes causing encephalitis, and wolves, coyotes and bears. Other carnivores may sustain subclinical infections. The disease occurs commonly worldwide, but is uncommon where vaccination is practiced.