Molecular characterization of HLJ-073, a recombinant canine coronavirus strain from China with an ORF3abc deletion

Chen, Si; Liu, Dafei; Tian, Jin; Kang, Hongtao; Guo, Dongchun; Jiang, Qian; Liu, Jiasen; Li, Zhijie; Hu, Xiaoliang; Qu, Liandong

Canine enteric coronaviruses (CCoVs) are important enteric pathogens of dogs. CCoVs with different variations are typically pantropic and pathogenic in dogs. In this study, we isolated a CCoV, designated HLJ-073, from a dead 6-week-old male Pekingese with gross lesions and diarrhea. Interestingly, sequence analysis suggested that HLJ-073 contained a 350-nt deletion in ORF3abc compared with reference CCoV isolates, resulting in the loss of portions of ORF3a and ORF3c and the complete loss of ORF3b. Phylogenetic analysis based on the S gene showed that HLJ-073 was more closely related to members of the FCoV II cluster than to members of the CCoV I or CCoV II cluster. Furthermore, recombination analysis suggested that HLJ-073 originated from the recombination of FCoV 79-1683 and CCoV A76, which were both isolated in the United States. Cell tropism experiments suggested that HLJ-073 could effectively replicate in canine macrophages/monocytes and human THP-1 cells. This is the first report of the isolation of strain HLJ-073 in China, and this virus has biological characteristics that are different from those of other reported CCoVs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00705-019-04296-9) contains supplementary material, which is available to authorized users.