Feline panleukopenia, a highly contagious and often fatal disease of cats, is caused by feline panleukopenia virus (FPV) or canine parvovirus (CPV), both strains of Carnivore protoparvovirus 1. Clinical disease has rarely been seen in Australia since the mid-1970s until 2014, when an outbreak was reported to a national online disease surveillance reporting tool.

The aim of this study was to determine the strains of canine protoparvovirus 1  and epidemiological factors involved in outbreaks of feline panleukopenia reported since 2014. Veterinarians and shelter owners were contacted to arrange site visits, collect samples and obtain information about animal movements, biosecurity and vaccination protocols for qualitative analysis. DNA was extracted from faeces or tissues of representative cats from each outbreak with clinical signs of panleukopenia and/or positive faecal antigen CPV tests, for PCR and sequencing of the VP2 gene. Phylogenetic analysis of outbreak and CPV-like and FPV-like VP2 sequences available on GenBank was performed using the maximum likelihood method.

Three outbreaks causing over 350 fatalities were identified in: (A) 2014, Melbourne; (B) 2015, Melbourne and Mildura, a city 540 km from Melbourne; (C) 2016, Melbourne and Sydney. Outbreaks in Mildura and Melbourne were caused by identical or closely related FPV genotype(s), while the Sydney outbreak was caused by a different FPV genotype. Most cases were from municipal, charitable or private shelters. Shelters with the highest number of fatalities did not perform routine vaccination. In shelters that did administer vaccines, disease occurred in incompletely vaccinated cats or cats not vaccinated due to respiratory disease. Movement of unvaccinated cats from municipal shelters to networks of private foster carers was identified in all outbreaks, including between Melbourne and Mildura in outbreak B. The median age of cats at diagnosis was 8 weeks. All outbreaks occurred from summer to autumn, coinciding with peak shelter intakes of kittens.

Feline panleukopenia, caused by FPV, has re-emerged as a major cause of mortality in Australian feline shelters in association with inadequate vaccination and biosecurity practices.

Disclosures

Disclosures to report
This study was funded by grants from the NSW Cat Protection Society and the Australian Companion Animal Health Foundation, IRMA Project ID 1822469.