“How long should I leave it before introducing a new rabbit after an outbreak of RHD2”
We are getting asked this question, or a variation of it very regularly. This is a really difficult question to answer, for several reasons.
Firstly, the virus is incredibly resilient in the environment, at least in ideal experimental conditions eg in organ suspensions held at 4C, where it can survive for greater than 7 months. In less artificial conditions eg cool, not dry, protected from UV light, and in/on organic material, eg carcasses, it has been shown to survive for at least 3 months (as the experiment stopped at that point, it could survive for longer than this). Less optimal conditions, where the virus is cooled but kept dry, give survival times of less than one month.
Another study showed excretion of virus for 2 months in rabbits which recovered from the virus.
As a result, quarantine periods of between a month and 7 months have commonly been suggested before exposing a new rabbit to previously infected or in contact rabbits, or environments where the virus has been shed, and it is difficult to propose a one size fits all exact period of time to guarantee biosecurity without suggesting a potentially significantly excessive duration.
We would suggest at least 2 months before bringing a rabbit into contact with the survivors of an outbreak.
We would suggest thorough cleaning and disinfection of any non-porous inanimate objects or surfaces in contact with infected animals, and either disposal of or cleaning following soaking in disinfectant for porous objects. Cleaning of cracks and corners of hutches etc is vital. Anigene and Virkon are both considered suitable for this type of cleaning, but make sure you follow their instructions.
Grass and earth are difficult to disinfect, but exposure to high temperatures and UV light in sunlight should inactivate it within approximately a month (although particular care should be taken if there are microclimates of moist cool conditions with organic material present: faeces, food, hay etc should be removed to allow exposure of the surfaces).
A period of at least 3 months is probably sufficient to eliminate the virus in bodies or protected suitable organic material (eg parts of bodies) in all but experimentally perfect conditions, and so a widely used period of 4 months is understandable.
However, this needs to be balanced against the welfare issues of sole or unsuitably housed rabbits, and the risk can be reduced (although never to zero, as no vaccine is 100% protective) by vaccination with a suitable RHD2 vaccine.
It is impossible to give a reply that is suitable for everyone and you should discuss your own situation with your vet. However, our general advice is:
Make sure all rabbits are vaccinated against RVHD2
Thorughly clean the area
Wait at least 2 months before introducing another (vaccinated) rabbit