ABSTRACT
Recently pseudorabies outbreaks have occurred in many vaccinated farms in China. To identify genetic characteristics of pseudorabies virus (PRV) strains, we obtained the genomic sequences of PRV strains HeN1 and JS, which were compared to 4 PRV genomes and 729 partial gene sequences. PRV strains isolated in China showed marked sequence divergence compared to European and American strains. Phylogenetic analysis revealed that for the first time PRV can be divided into 2 distinct clusters, with Chinese strains being genotype II and PRVs isolated from other countries being genotype I. Restriction fragment length polymorphism analysis confirmed differences between HeN1 and Bartha strains, as did the presence of unique insertion/deletion polymorphisms and microsatellites. This divergence between the two genotypes may have been generated from long-term, independent evolution, which could also explain the low efficacy of the Bartha vaccine in protecting pigs infected with genotype II PRV.
Subject(s)
Genetic Variation , Herpesvirus 1, Suid/classification , Herpesvirus 1, Suid/genetics , Pseudorabies/epidemiology , Pseudorabies/virology , Animals , China/epidemiology , Cluster Analysis , DNA, Viral/chemistry , DNA, Viral/genetics , Genome, Viral , Genotype , Herpesvirus 1, Suid/isolation & purification , Molecular Epidemiology , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA , Sequence Homology , SwineABSTRACT
Through routine and nested PCR amplifications, four complete genome sequences of porcine Torque teno virus (TTV) type II were obtained from swine herds. By comparison with the TTV genome sequences deposited in GenBank, we found the most divergent types so far described. The level of genetic diversity between these genomes is higher than would be expected within a single virus species. A nucleotide and amino acid phylogenetic tree was constructed.
Subject(s)
Genome, Viral , Torque teno virus/genetics , Animals , DNA, Viral , Databases, Genetic , Genes, Viral , Genetic Variation , Molecular Sequence Data , Open Reading Frames , Phylogeny , SwineABSTRACT
Here, we report three complete genome sequences of porcine torque teno virus type I (TTV1) which were obtained from swine tissues and sera from southern China through routine and nested PCR amplification and characterized together with other genome sequences already deposited in GenBank. The results showed that the TTV1 sequences were highly divergent and could be divided into 1a and 1b subtypes.
