Canine parvoviruses (CPVs) and feline panleukopenia virus (FPV) are strains of Carnivore protoparvovirus 1. CPV2a-c can infect and replicate in both canids and felids. Using conventional PCR, a recent study reported a high prevalence of faecal shedding of CPVs among asymptomatic shelter cats in the UK, identifying cats as a potential reservoir of infection.

The aim of this study was to determine the prevalence of faecal shedding of CPVs in asymptomatic shelter-housed cats in Australia. One hundred stool samples from unvaccinated cats housed in a dual canine/feline shelter were collected and stored at -80°C until testing. Viral DNA was extracted from faeces by homogenisation of a 10% w/v solution of faeces in phosphate-buffered saline (PBS), boiling of the supernatant after centrifugation, chilling on ice and repeat centrifugation. To identify PCR inhibition in faecal DNA extracts, dilutions (1:10 and 1:20) of supernatant were spiked with feline genomic DNA (138 ng) and tested using a PCR amplifying the feline GAPDH gene. Feline GAPDH was amplified in all spiked faecal samples at a 1:20 dilution, and in 99 samples at a 1:10 dilution. PCR inhibition of GAPDH in one sample at 1:20 dilution was abolished at a 1:50 dilution.

Faecal DNA extracts (1:10 and 1:20 dilutions [n=99], 1:50 dilution [n=1]) from shelter cats were screened for the presence of CPV and FPV using a PCR assay amplifying a 529 bp region of the VP2 gene using primers 555-F and 555-R. PBS processed in parallel with samples from extraction to PCR served as a negative control and DNA from a previously sequenced canine CPV isolate as a positive control. In samples testing positive, the complete VP2 gene was sequenced to differentiate FPVs from CPVs. CPV DNA was not detected in the stool of any cat. FPV DNA was detected in the stool of 4 cats.

In contrast to results of a UK shelter, faecal shedding of CPV by asymptomatic shelter-housed cats was not detected in this study, and the prevalence of FPV shedding was low. Future studies to screen for Carnivore protoparvovirus using quantitative PCR assays are warranted to rule out low-level shedding undetectable by conventional PCR.

Disclosures

Disclosures to report
Conflict of interest: The authors declare no potential conflict of interest regarding research, authorship and/or publication of this article.

Funding: The authors received research grants from Boehringer Ingelheim PTY LTD, 78 Waterloo Rd, Macquarie Park, NSW 2113 Australia, and the University of Sydney, Camperdown, NSW 2006 Australia.