Complete genome sequence analysis of canine bocavirus 1 identified for the first time in domestic cats

Abstract

In this study, we investigated the presence of canine bocaviruses (CBoVs) in fecal samples from 105 cats with diarrhea and 92 asymptomatic cats in northeast China. One fecal sample, 17CC0312, collected from an asymptomatic cat, was found to be positive for canine bocavirus 1 (CBoV1). The nearly complete genome of this virus was cloned and sequenced. The viral genome was 5,069 nucleotides (nt) in length and combined four open reading frames (ORFs) in the order 5'-NS1-ORF4-NP1-VP1/VP2-3'. The 17CC0312 virus shared more than 90.3% nucleotide sequence identity with CBoV1 reference sequences and was placed within the CBoV1 group in a phylogenetic tree based on complete genome sequences. Further phylogenetic analysis based on the deduced amino acid sequence of the VP2 gene showed that this feline CBoV1 strain belongs to CBoV1 lineage 3. These data provide the first molecular evidence of the presence of CBoV1 in a domestic cat and suggest that cats might be carriers of CBoV1.

Fig. 1

Comparative genome organization of canine bocavirus 1 strain 17CC0312 identified in cats in this study and other reference strains of canine bocavirus 1. Grey boxes labelled “Exon 2” represent the second exon of the NS1 protein, and arrows indicate RNA-splicing sites

Fig. 2

Phylogenetic analysis based on the nucleotide sequence of full-length genome (a) and the deduced amino acid sequences of the complete VP2 gene (b). A multiple alignments including the sequences of 17CC0312, canine bocavirus reference strains, and FBoV reference strains as an out-group were performed using the Clustal W program, and phylogenetic trees were constructed using the neighbour-joining method with 1,000 bootstrap replicates, and only bootstrap values > 70% are displayed above the tree branches. The strain names, country, year of isolation, GenBank accession number, percent sequence identity (in parentheses) compared to 17CC0312, and the species of the canine bocavirus are shown in each phylogenetic tree. CBoV-2 lineages proposed in the present study are only shown in the phylogenetic tree based on the complete VP2 protein sequence (b). A black square indicates CBoV1 strain 17CC0312 identified in cats in the present study

Fig. 3

Similarity plot analysis of the complete genome sequences of 17CC0312 (blue), four CBoV1 reference strains, including Con-161 (green), 13D009 (violet), 14Q216 (red) and GZHD15 (pink), CnMV strain HM-6 (gray) and CnBoV3 strain UCD (black) as out-group sequences, and CBoV1 strain HK831F as a query sequence, using the Kimura 2-parameter model with a sliding window of 200 nt and a moving step size of 20 nt. The NS1, NP1, VP1 and VP2 regions are separated by red lines, and the nucleotide positions refer to the full-length genome sequence of CBoV1 strain HK831F