Monday, January 5, 2015

Warning for pet rabbit owners

Boris the bunny needs some additional protection from a novel variant strain of Rabbit Haemorrhagic Disease Virus.
Do you own a pet rabbit and live in NSW? Do you treat rabbits in your practice? If so you should be aware of a new strain of Rabbit Haemorrhagic Disease Virus (RHDV), also known as calicivirus, which has been detected over the last 12 months.

According to a memo from Chief Veterinary Officer Ian Roth, reported cases occur in an area from South Sydney to Kyogle and as far west as Lithgow. In all locations, sudden deaths have occurred. The most commonly affected are young rabbits (4-6 weeks old) and those not recently vaccinated.

This strain, first identified in China, is rapidly replacing endemic strains in a number of countries. Poor vaccination rates in rabbits are allowing it to take hold.

(The endemic strain of RHDV here is the Czech strain, for which the Cyclap vaccine provides protection. Limited studies have shown this vaccine provides "some" protection from the novel variant strain, although protection isn't guaranteed).

Vets should be aware that the manufacturers have made some “off-label” suggestions for use of vaccine to provide additional protection to bunnies.
Here is some info direct from the memo:

The incubation period for the RHDV is between 1 to 3 days, with death following 1 to 2 days after this period. Most rabbits will show no signs of external symptoms of RHD but may have signs of haemorrhage on post mortem.
Transmission of RHDV occurs by direct contact with an infected animal or fomites. Rabbits acquire RHDV through oral, nasal or conjunctival pathways. Virus may be present in urine, faeces and respiratory secretions. The virus may also be carried by the wind, flies, rabbit fleas and mosquitoes. [Ed: another good reason to provide rabbits with indoor housing].
Any veterinarian who suspects a domestic rabbit may have RHDV, should submit a fresh frozen (not formalin-fixed) 1 g liver sample to the State Diagnostic Veterinary Laboratory (SVDL) at the Elizabeth Macarthur Institute (EMAI) .See
If you live in or near the affected areas, the recommendations are for increased vaccination and health care protocols. These include:
  • Early vaccination (at 3-4 weeks) and repeat at monthly intervals with the final kitten vaccination at 2.5 to 3 months of age
  • More frequent boosters (eg every 6 months) if required
  • Maintaining excellent biosecurity including:
  • preventing contact between domestic and wild rabbits,
  • avoid cutting grass and feeding it to rabbits if there is the risk of  contamination from wild rabbits,
  • washing hands between handling rabbits,
  • good insect control is also important and will help reduce the risks of introduction of both RHDV and myxomatosis,
  • infected rabbits should be isolated and disposed of in a manner that will minimise environmental contamination,
  • all cages and equipment should be thoroughly cleaned and disinfected.