Isolation and Genetic Characterization of Emerging H3N2 Canine Influenza Virus in Guangdong Province, Southern China, 2018-2021.

Feiyan Zheng,Jiajun Ou,Shaotang S Ye,Jia Kun,Jiaojiao Cheng,Cundong Ye,Gang Lu,Shoujun Li

doi:10.3389/fvets.2022.810855

Abstract

H3N2 canine influenza virus (CIV) emerged in dogs in China or Korea around 2005 and was first reported in 2008. In 2015, H3N2 CIV was detected in the United States and caused a huge outbreak. To date, H3N2 CIV is continuously circulating in dog populations in China, Korea, and the United States. For continuous monitoring of H3N2 CIV in China, we collected 180 dog nasal swab samples and 196 cat nasal swabs from veterinary hospitals in Guangdong Province between 2018 and 2021. Six emerging H3N2 CIV strains were isolated. Following full genome sequencing and phylogenetic analyses, we found that A/canine/Guangdong/1-3/2018 and A/canine/Guangdong/1-3/2021 diverged from the reported sequences of the Chinese H3N2 CIV strains. Moreover, we found that these H3N2 CIV strains belong to the group that contains US and northern China CIV strains in 2017 and 2019 and dominate in the dog population until 2021.

Highlights

Influenza is a highly contagious and acute infection that usually occurs in the upper respiratory tract and has been detected in many vertebrate hosts worldwide
In the analysis of the comparison of amino acid sequences of all H3N2 canine influenza virus (CIV) strains in the NCBI database (Table 4), we found that the hemagglutination assay (HA) amino acid sequences of H3N2 CIV strains in this study all had V128I mutations, and GD strains in 2018 had N187S, A289S, N/T328S, and N481S mutations
Based on the phylogenetic analysis, we found that the HA and NA genes of H3N2 CIV can be divided into four groups: group A is Chinese CIV strains, group B is Korean CIV strains, group C is mainly American strains and northern China strains in 2017, and group D is mostly American strains and domestic strains isolated after 2018

Summary

Introduction

Influenza is a highly contagious and acute infection that usually occurs in the upper respiratory tract and has been detected in many vertebrate hosts worldwide. Dogs and cats are exposed to the risk of influenza virus infection. A few epidemiological and experimental infection studies in the 1970s indicated that dogs could be infected with IAV, the IAV strain was not isolated from dogs until 2004. This virus is known as canine influenza virus (CIV), which is responsible for canine influenza (CI), a respiratory disease with the clinical features of cough, sneeze, fever, and nasal discharge in dogs [1, 2]. H3N2 CIV was reported in China by our laboratory, indicating that this virus was circulating in the Chinese dogs in 2006 [6, 7]

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Conclusion