Disease in dogs caused by canine parvovirus (CPV) is common in Australia. A related strain of canine protoparvovirus 1  (CPPV1), feline panleukopenia virus (FPV), re-emerged in 2014 in Australia as a major pathogen in shelter cats. In North America and Europe, wild carnivore hosts are implicated in the emergence of novel strains of CPPV1. Australia has large populations of introduced feral carnivores including cats (Felis catus) and foxes (Vulpes vulpes) as well as endemic carnivores such as the endangered Tasmanian devil (Sarcophilus harrisii).

The aim of this study was to i) determine whether there is evidence of CPPV1 infection in feral carnivores and viral traffic between these and companion animals; (ii) model in silico the susceptibility of the Tasmanian devil to CPPV1. Reticuloendothelial tissue samples were sourced from deceased feral carnivores for PCR amplification and sequencing of a 529 bp region of the CPPV1 VP2 gene. Phylogenetic analysis of partial VP2 gene sequences was performed using the maximum likelihood method. Tasmanian devil susceptibility to infection was investigated by comparison of their transferrin receptor type 2 (TfR) sequence at binding sites for CPPV1 to susceptible carnivores, and phylogenetic analysis of TfR protein.

Tissue samples from 62 feral cats and 53 foxes collected between 2010 and 2016 were analysed. CPPV1 DNA was detected in 14/62 feral cats and 0/53 foxes. CPPV1-positive cat samples, all from animals culled in 2010, comprised 5 related FPV genotypes, including one genotype identical to that detected in FPV outbreaks in cat shelters in Melbourne (2014–2016), and another that was closely related to an FPV strain identified in a Burmese kitten in Melbourne in 1970. TfR amino-acid residues 224 and 389, critical to parvovirus binding, are glutamate and arginine, respectively in Tasmanian devil TfR, in contrast to leucine and lysine or asparagine in canid and felid hosts. Tasmanian devil TfR protein was only distantly related to these hosts.

This study provides evidence of feral cat reservoirs of CCPV 1 infection and viral traffic between feral carnivores and companion animals in Australia. TfR gene analysis indicates that Tasmanian devils are unlikely to be susceptible to CCPV1, which has important biosecurity implications for captive breeding programs.

Disclosures

Disclosures to report
This study was funded by the Australian Companion Animal Health Foundation, A University of Sydney Charles Perkins Centre Fellowship grant and Boehringer Ingelheim.