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.

犬腺病毒 (CAV) 有两种类型：犬腺病毒 1 型 (CAV-1)，可引起传染性犬肝炎；犬腺病毒 2 型 (CAV-2)，主要与犬的呼吸道疾病有关。由于广泛使用改良活疫苗来控制犬腺病毒感染并随后降低了疾病发病率，CA​​V 经常被临床医生忽视。尽管有许多关于印度 CAV-1 流行情况的研究，但有关 CAV-2 的信息很少。这项研究报告了一只接种疫苗的狗出现 CAV-2 感染，并出现神经和呼吸道症状，该狗对其他犬类病原体（如犬瘟热病毒和犬细小病毒）呈阴性。从MDCK细胞直肠拭子中成功分离出该病毒，并通过免疫荧光测定和病毒中和试验进行表征。在部分 E3 区域的系统发育分析中，印度 CAV-2 分为与已建立的亚群不同的独立进化枝。据报道，在印度 CAV-2 分离株的 E3 基因的第 1077 位核苷酸 (nt.) 处插入了“G”核苷酸，导致 E3 基因编码区发生移码，从而在其 C 末端赋予了额外的 11 个氨基酸与世界其他地区的隔离者相比。这可能对 E3 蛋白在细胞内的功能作用有影响。这项研究强化了印度 CAV-2 E3 基因中的独特标记插入，也是世界上第二项报告 CAV-2 与狗神经系统疾病关联的研究。