Outbreaks of virulent systemic feline calicivirus in NSW

There have been outbreaks of suspected feline calicivirus-virulent systemic disease (FCV-VSD) at two veterinary practices in Sydney between December 2015 and January 2016. Several cats died from severe disease as a result.

Affected cats presented with some or all of the following signs - fever, limb and/or head oedema, oral ulceration, crusted nasal sores, purulent skin ulcers, ear-tip necrosis, jaundice and dyspnoea. These clinical signs are similar to those reported in previous epizootic outbreaks of FCV-VSD strains overseas.

While typical FCV infections in cats are characterised by oral ulcers, upper respiratory signs and transient lameness, VSD is characterised by a severe systemic inflammatory response syndrome with vasculitis and hepatocellular necrosis. Signs of FCV-VSD are more severe in adult cats than in kittens and fatalities are common.

FCV can survive in the environment for around one month. FCV strains that cause VSD are highly contagious and easily transmitted by clothing, shoes, bedding, food bowls and litter trays. Owners of affected cats should ensure they wash all these items if there are other cats in the household.

Vets who see pyrexic, systemically unwell cats who may have the disease must keep them isolated from other cats, and employ effective barrier nursing, good hand hygiene and wash down surfaces to prevent spread to other cats. Effective disinfectants include sodium hypochlorite (1:32 dilution of a 5-6% solution) and potassium peroxymonosulfate (e.g. Virkon).

Vaccination against FCV cannot be assumed to protect cats from VSD. Although vaccination was shown to provide some protection experimentally, previous reports of FCV-VSD outbreaks have shown that cats fully vaccinated for FCV can still succumb to FCV-VSD.  

The emergence of virulent strains of FCV is most likely to occur in multi-cat environments such as shelters or boarding catteries where high levels of FCV infection and replication create ideal conditions for de novo mutations of field strains of FCV. Outbreaks of VSD can also occur when cats from such environments are transported to another multi-cat environment. Fortunately, progressive spread into the wider community has not been recorded and most localised outbreaks tend to “burn-out” by themselves.

Cats infected with field strains of FCV that are co-infected with feline panleukopenia virus can also develop severe illness that may mimic FCV-VSD so testing for FPV is recommended in suspected cases (faecal antigen test for canine parvovirus, and/or faecal PCR).

Researchers at the University of Sydney are investigating the viral strains responsible for the Sydney outbreak. To discuss suspected cases or for further information, please contact Professor Vanessa Barrs (vanessa.barrs@sydney.edu.au)

     Privacy Policy  |  Disclaimer  |  Contact us