Genetic characterization of a novel group of H3N2 canine influenza
viruses isolated from Guangdong Province in southern China in 2018
Abstract
Canine influenza virus (CIV) is an emerging pathogen that can infect
canines, causing a series of respiratory symptoms. H3N2 CIV emerged in
dogs in China and Korea in approximately 2005 but was first reported in
2007. In 2015, H3N2 CIV was detected in the USA, where it caused a large
outbreak. For continuous monitoring of H3N2 CIV in China, a total of 180
dog nasal swabs were collected from veterinary hospitals in southern
China between 2017 and 2018 and tested for CIV RNA. Three H3N2 CIV
strains were isolated. Following genome sequencing, sequences of the
isolates were found to be divergent from the sequences of reported
Chinese H3N2 CIV strains. Phylogenetic analyses indicated that these
viruses are clustered in a novel group and genetically close to strains
from the USA. Several unique aa substitutions in HA and NA were observed
in the H3N2 CIV strains isolated in this study. These findings reveal
unique evolutionary characteristics of recently identified H3N2 CIV
strains in China.