Canine adenovirus type 2 (CAV-2)
infection results in significant respiratory illness in
dogs. Isolating and culturing CAV-2 allows for investigations into its pathogenesis and the development of
vaccines and diagnostic assays. In this study, we successfully isolated a
virus from a naturally infected
dog in Gyeonggi-do,
Korea. The
virus was propagated in Madin-Darby canine
kidney (MDCK) and
Vero cells and showed a specific cytopathic morphology that appeared
similar to a bunch of
grapes. The
virus was first confirmed as CAV-2 based on these cytopathic effects, an
immunofluorescence assay,
hemagglutination assay, and
electron microscopy. The viral titer of the isolate designated APQA1601 reached 10(6.5) 50%
tissue culture infections dose per mL in
MDCK cells and exhibited no
hemagglutination units with
erythrocytes from
guinea pig. The
virus was also confirmed by
polymerase chain reaction and
next-generation sequencing. The APQA1601
strain had the highest similarity (~99.9%) with the Toronto A26/61
strain, which was isolated in
Canada in 1976 when the
nucleotide sequences of the full
genome of the APQA1601
strain were compared with those of other CAV
strains. Isolating CAV-2
will help elucidate the
biological properties of CAV-2 circulating in Korean
dogs.