Detection of a canine parvovirus type 2c with a non-coding mutation and its implications for molecular characterisation

An epidemiological survey for canine parvovirus (CPV) was conducted by collecting 615 faecal samples from dogs with diarrhoea in different European countries. Molecular methods showed that CPV-2a was predominant in most countries, followed by CPV-2c and CPV-2b, whereas 30 strains were not characterised. By sequence analysis of the full-length VP2 gene, 20 of these viruses were characterised as CPV-2c mutants having the synonymous mutation A4061G in the probe-binding region that prevented correct strain characterisation. A real-time polymerase chain reaction (PCR) assay using a minor groove binder probe was able to recognise both mutant and classical CPV-2c strains. These results indicate that the emergence of CPVs with mutations affecting the oligonucleotide-binding region needs a continuous update of molecular diagnostic tools in order to detect efficiently those emerging strains.