Molecular analysis of a fragment of gene E1B 19K of canine adenovirus 2 (CAV-2) isolated from dogs with symptoms of cough

Isolation and genetic characterization of canine adenovirus type 2 from a domestic dog showing neurological symptoms

Canine adenoviruses (CAVs) are of two types: canine adenovirus type 1 (CAV-1), which causes infectious canine hepatitis, and canine adenovirus type 2 (CAV-2), which is mainly associated with the respiratory type of disease in dogs. Due to the widespread use of modified live vaccines to control canine adenoviral infections and subsequently reduced disease incidence, CAVs are often neglected by clinicians. Although a number of studies are available about CAV-1 prevalence in India, only meagre information is available about CAV-2. This study reports the CAV-2 infection in a vaccinated dog with neurological and respiratory symptoms which was found negative for other canine pathogens like canine distemper virus and canine parvovirus. The virus was successfully isolated from rectal swab in MDCK cells and characterized by immunofluorescence assay and virus neutralization test. On phylogenetic analysis of partial E3 region, the Indian CAV-2 grouped in a separate clade different from established subgroups. An insertion of "G" nucleotide was reported at nucleotide (nt.) position 1077 in the E3 gene of Indian CAV-2 isolates which led to a frameshift in the coding region of E3 gene thereby imparting additional eleven amino acids to its C-terminal end in comparison to isolates from other parts of the world. This may have an implication on the functional role of E3 protein inside the cell. This study reinforces the unique signature insertion in the E3 gene of Indian CAV-2 and is the second study in the world to report the association of CAV-2 with neurological disease in dogs.

Investigation of the presence of canine adenovirus (CAdV) in owned dogs in Northern Italy

The use of a modified live canine adenovirus (CAdV) vaccine has greatly reduced the incidence of infectious canine hepatitis (ICH) in dogs. Nevertheless, cases of CAdV type 1 and 2 (CAdV-1 and CAdV-2) infection have been recently reported posing questions about the epidemiological situation of CAdV in dogs. In order to assess the presence of CAdV, samples from 51 dogs presented at a Veterinary Teaching Hospital in Bologna, Italy, for reasons unrelated with CAdV infection, were tested with a polymerase chain reaction (PCR) assay for CAdV. Thirty dogs (58.8%) were PCR positive for CAdV-2 infection and four of them (7.8%) were positive for CAdV-1. Sequence analysis performed on the obtained PCR products suggests that a genetically stable CAdV-1 strain and different CAdV-2 strains circulate in the canine population examined and that coinfections are relatively frequent.