Partial DNA cloning and sequencing of a canine parvovirus vaccine strain: application of nucleic acid hybridization to the diagnosis of canine parvovirus disease

The cloning and sequencing of anEco RI-Pst I fragment derived from the replicative form of a canine parvovirus (CPV) vaccine strain are reported. The variability of the 5′ end of NS 1 protein gene in the genome is confirmed by comparison with previously determined DNA sequences. A 15 nucleotide deletion was also observed in this vaccine strain. In order to improve CPV diagnosis, radioactively labelled RNA or DNA and biotin labelled DNA obtained by random priming of the recombinant plasmid were used as probes mainly on gut or stool samples from naturally infected dogs. Results of filter hybridization correlated well with histopathological diagnosis of parvovirus infection and with hemagglutination tests performed on dog faeces. We propose that nucleic acid hybridization may be an alternative diagnostic method to ascertain the presence of CPV, especially in frozen samples.