Analysis on the complete genome of a novel caprine parainfluenza virus 3.

Parainfluenza virus type 3 (PIV3) is one of the most important viral respiratory pathogens for humans and for many animals. One unique caprine PIV3 (CPIV3) strain named JS2013 was isolated in Chinese goat flocks with respiratory diseases in 2013. Now, the complete genome sequence of the strain JS2013 had been determined. A total of 15 overlapping DNA clones, covering the entire genome of the virus, were obtained by primer walking RT-PCR. The sequences of the 3' and 5' termini of the viral genome were amplified by 3' and 5' RACE. The viral genome was 15,618 nucleotides (nt) in length, which was consisted of six genes in the order 5'-leader-N-P/C/V-M-F-HN-L-tailer-3'. The junction sequences between two genes were highly conserved gene start and stop signal sequences, and trinucleotide intergenic regions (IGR) similar to those of other reported PIV3 strains. Phylogenetic analysis based on the complete genomes of JS2013 with other strains of genus Respirovirus demonstrated that the JS2013 obviously differed from HPIV1, Sendai virus, HPIV3 and other reported BPIV3 genotypes. Further analysis of HN genes of JS2013 along with two more CPIV3 strains isolated later indicated that CPIV3 strains formed a separate cluster. The results presented here suggested that CPIV3 is a new member of the genus Respirovirus.