This supersedes earlier advice
 There are two strains of RVHD, known as RVHD1 and RVHD2.  Both strains are lethal and you must vaccinate to protect your rabbits.  RVHD2 has been in the UK since 2013 and over time appears to be overtaking classic RVHD as the primary strain.

RVHD vaccines are very effective. Your rabbits can currently be protected against RHD1 using the Nobivac Myxomatosis-RHD vaccine with a booster every 12 months. Both strains of RVHD are covered by vaccination any time from ten weeks (Filavac) or RHD2 can be prevented from 30 days (Eravac) of age. The separate RVHD2 vaccine is given every 6-12 months. You should consult your vet for the best combination currently available for your rabbit(s).

It’s very important to clean and disinfect anything that may be carrying the viruses, including water bottles, bowls, bedding and housing.  This means that boarding and rescue rabbits, even with up to date vaccinations, may potentially be a risk, and establishments should take suitable precautions, as should vets who may have infected rabbits brought to them for treatment. Anything that has been touched by an unknown rabbit should be thoroughly cleaned and treated with virucidal agents. In high risk situations foot covers or foot dips may be wise measures.

If you are about to obtain a young rabbit that hasn’t yet been vaccinated:

  • Follow the advice given in the vaccinations section
  • Don’t use second-hand hutches or equipment without finding out what happened to the previous occupant.

FAQ on Rabbit Viral Haemorrhagic Disease 1 and 2 Background:

For background, whilst the “classic” RVHD has been present in the UK for decades, variant RHVD (also known as RHVD2 or RHDV variant) was first noted in 2010 in France, and has subsequently been identified in the UK (OIE Technical Disease Cards, updated July 2015; Abrantes et al, 2012; Dalton et al, 2012; Westcott and Choudry, 2014). This virus has some differences from the classic RVHD. In particularly it may affect rabbits of any age, as opposed to RVHD1, which is rarely if ever seen in rabbits under 8-10 weeks of age.

It has also been reported that the variant gives rise to lower mortalities than classical RVHD, this is not necessarily borne out by reports (Abrantes et al, 2013), and this may be thought to be due to be the case due to its phylogenetic placement alongside non-pathogenic strains.

Mortality may vary from collection to collection, and possibly from breed to breed. The only vaccine for rabbits initially available with a UK License was Nobivac Myxo-RHD (MSD Animal Health), which was made available in 2012. Not long after that, the other 3 vaccines against RHVD on the UK market ceased to be available.

This vaccine does not appear to offer protection against RVHD2, and neither do the previous vaccine brands available in the UK. However, RHD1 and Myxo remained the most significant health threats which could be vaccinated against, and so coverage with this product remains a priority. Work from Italy and France, however, suggests that, with our reservoir of wild rabbits, we can expect to see RHD2 starting to predominate over RHD1 in the next 5 years or so.

However, there are now 2 vaccines available in the EU which have been licensed or are undergoing licensing for efficacy against RVHD2, and may be used in the UK without a special import or treatment certificate.  Filavac VHD K C+V and Eravac are available through UK wholesalers.

Stocks are sometimes very variable, and practices are advised to contact wholesalers directly for information on stock availability. I would still be interested in any other practitioners findings regarding reports of suspected or confirmed RHD1 and 2.

 FAQs

Is vaccination necessary?

This will obviously involve a risk assessment of the individual rabbit(s), but the wide geographical range of the disease, and the reported losses of several hundred rabbits throughout the UK, as well as molecular testing confirmation of cause of death in many sampled, suggests that vaccination is strongly advisable.

Moredun Institute has advised RWAF that cases have been confirmed throughout the UK, so you cannot assume you are in a ‘safe’ area. Additionally we believe that RVHD2 will be significantly under reported. Because RHD2 doesn’t always look like classic RHD1, a rabbit could be taken into hospital looking ill, but nobody would necessarily think to treat that potentially infectious case for RHD2

Do existing RHD1 vaccines work? Because the mortality rate is lower with RHD2, any test using a small number of rabbits could easily show protection just because none of them were going to die anyway. There is some anecdotal evidence that RHD1 vaccines have some short term effect, but nothing peer reviewed. Le Gall-Recule (2013) showed that cross immunity between RHD1 and 2 was, at best, partial.

Do RHD2 vaccines work? Le Minor et al (2013) showed that Filavac produced good immunity (full protection) against RHD2 in challenge studies. (15èmes Journées de la Recherche Cunicole, 19-20 novembre 2013, Le Mans, France)

How will you get it from your vet?

Please only go through your vets, rather than contacting wholesalers directly.

What dose regime is suggested?

Standard advice with immunological products not licensed for simultaneous administration is to space them out by at least 2 weeks, and this is the regime we advise with both vaccines.

The duration of immunity for Filavac has been established at at least 12 months, in laboratory conditions in healthy rabbits. The manufacturer’s advice is to administer a single dose of the vaccine, followed by annual boosters in low risk situations, and 6 monthly in the case of breeding does at high risk. In the UK, I would suggest that high risk situations include rescue centres and breeders, unless they have a strict quarantine policy, and those rabbits which have greater contact with wild rabbits, as well as any geographical location where cases have been reported recently. All other rabbits are likely to fall into the lower risk category, requiring annual re-vaccination. The duration of immunity has not been confirmed in the case of Eravac, but this is expected to be updated shortly.

What does the vaccine cost?

Here at the RWAF we are not able to monitor or affect the prices charged by veterinary practices. It’s worth pointing out that the price of the vaccine may vary widely between practices due to pricing structures, and due to the caseload of rabbits that they see. If they are able to make use of larger vaccine vials, the cost may be shared across more rabbits and reduced, but this is not often possible, as it requires enough rabbits to be seen in a 2 hour window during which the vial may be used.

What if I buried my pet rabbit and now wonder if it was RVHD 2, will the ground be infected and a risk to my other rabbits? (How should bodies be disposed of?)

There is not enough information out there to know the correct answer to this. We know it can live for 200 days in ideal conditions, so there is in theory a potential risk but we are speculating here. The best way to dispose of the body of any rabbit that died a sudden or unexplained death is to ask your vet to get it cremated for you. Double wrap them in plastic, and disinfect the outside, before taking to your vet, to reduce the risk of disease spread.

Once rabbits have recovered from RVHD2 do they still carry it? Do they still shed? Can I bond to another rabbit safely without risking them?

There is not enough information known about RVHD2 to know the correct answer to this with any certainty. In theory they should be safe to bond after 200 days, in practice it may be safe sooner than this, but we really don’t know.

Can you recommend a cleaning protocol?

90% of any disinfection is cleaning, that is the most important aspect. After thorough cleaning of the area to remove any scale or residue, use Ark-Klens , which is a benzalkonium chloride disinfectant and as such it should be effective against EC and myxi, to routinely disinfect the housing. Periodically use Virkon (as an inorganic peroxygen compound) to kill any other viruses. Note: Other benzalkonium chloride disinfectants and inorganic peroxygen compounds may be available, in addition to those named above.

Other than vaccination can I prevent my rabbit getting RHD? Will they get it from hay?

They are very unlikely to get RHD (1 or 2) or Myxomatosis from hay or barn dried grass. Risk / benefit analysis would be in the favour of feeding these foods. Foraged foods may potentially carry RVHD. Try to obtain plants from areas out of the reach of wild rabbits, and do not collect forage from areas of known wild rabbit RVHD infection. Biosecurity advice was given in the webinar (link above) but summarised here: Use foot dips or change footwear between going outside, especially into areas frequented by wild rabbits Quarantine new animals, feed them last, use new equipment such as bottles / bowls for them. Barrier nurse any suspicious cases Try to exclude wild rabbits and unless they can be excluded from the garden consider stopping the practice of moving pens around the garden and even consider a double fence round rabbit runs.

What are the risks of “over-vaccination” and vaccine ingredients?

Vaccinating with an RHD 1 and 2 vaccine (Filavac), 1-2 times per year, on top of an existing RVHD1 and Myxomatosis vaccine (Nobivac), obviously increases the vaccine frequency and amount given to each rabbit. This is not perfect, but the alternative is missing out one of these vaccines, and the risk of “over-vaccination” is considered lower than the risk of insufficient protection. Filavac is an inactivated, adjuvanted vaccine, and so cannot lead to clinical RVHD in the animal. Eravac covers only RHD2, and so there is less concern about “over-vaccination” with this product. Concerns are often raised about vaccine ingredients (adjuvants and excipients) such as aluminium hydroxide and sodium metabisulphite. This is too large a topic to discuss here, but, without dismissing these concerns out of hand, and after weighing the risks against the benefits, vaccination has a strongly net positive benefit against the diseases discussed here. There are known vaccine side effects discussed in the data sheets for these vaccines. They are usually limited to small local transient skin reactions, and transient mild lethargy. Oil based vaccines such as Eravac carry a known risk of skin and subcutaneous tissue damage, and great care must be taken to ensure no vaccine enters the intradermal route, to minimise this risk, as well as taking care not to accidentally self-inject. The frequency of vaccination, and a risk:benefit analysis for each individual, should be discussed between client and veterinary surgeon before deciding on an appropriate regime and vaccination plan. There is a risk to any animal (or person) to having any vaccination, which is why animals (or people) should only be vaccinated if they are healthy. For further general details on companion animals, the BSAVA and WSAVA vaccine guidelines should be consulted. Note that under their definitions, in the UK and mainland Europe, RHD2 would be considered a “core” vaccination.

https://www.bsava.com/Resources/Positionstatements/Vaccination.aspx http://www.wsava.org/guidelines/vaccination-guidelines Titre testing against this strain is not commercially available, at least at present in the UK. It’s also worth being aware that other countries are slightly ahead of us in arranging vaccine importation and use for domestic rabbits. In Holland, vaccination has been underway with Filavac for several months before its use in the UK, and they also use the Nobivac Myxo-RHD vaccine.

Refs: Joana Abrantes, Wessel van der Loo, Jacques Le Pendu and Pedro J Esteves (2012) Rabbit haemorrhagic disease (RHD) and rabbit haemorrhagic disease virus (RHDV): a review Veterinary Research 2012, 43:12 doi:10.1186/1297-9716-43-12 Kevin P. Dalton, Inés Nicieza, Ana Balseiro, María A. Muguerza, Joan M. Rosell, Rosa Casais, Ángel L. Álvarez, and Francisco Parra(2012) Variant Rabbit Hemorrhagic Disease Virus in Young Rabbits, Spain Emerg Infect Dis. 2012 Dec; 18(12): 2009–2012. doi: 10.3201/eid1812.120341 D. G. Westcott and B. Choudhury Rabbit haemorrhagic disease virus 2-like variant in Great Britain Veterinary Record doi:10.1136/vr.102830 Joana Abrantes, Ana M. Lopes, Kevin P. Dalton, Pedro Melo, Jorge J. Correia, Margarida Ramada, Paulo C. Alves,Francisco Parra, and Pedro J. Esteves New Variant of Rabbit Hemorrhagic Disease Virus, Portugal, 2012–2013 Emerg Infect Dis. 2013 Nov; 19(11): 1900–1902. doi: 10.3201/eid1911.130908 Detection of a new variant of rabbit haemorrhagic disease virus in France G. Le Gall-Reculé et al February 5, 2011 | Veterinary Record | 137-138 doi: 10.1136/vr.d697 Emergence of a new lagovirus related to Rabbit Haemorrhagic Disease Virus Ghislaine Le Gall-Reculé et al (2013) Veterinary Research 2013 44:81 DOI: 10.1186/1297-9716-44-81

Other useful sources of information: http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005087 http://www.iucn-whsg.org/RabbitHemorrhagicDiseaseInEurope https://www.harcourt-brown.co.uk/articles/infectious-disease/rabbit-haemorrhagic-disease Webinar: http://therabbitvet.com/webinar/vhd-rhd-2-update-rabbit-haemorrhagic-disease