RVHD2: The UK's Newest Fatal Rabbit Disease

This article aims to give a general overview of the current RVHD2 situation in the UK including information for veterinary professionals and owners regarding prevalence, prevention, vaccination, biosecurity and what to do if you have a sudden rabbit death. Links to further in-depth articles are also provided throughout and at the end.

General History

Rabbit Viral Hemorrhagic Disease (RVHD) and Myxomatosis (Myxo) are common diseases found throughout the UK and can be fatal to non-vaccinated rabbits. Both outdoor AND indoor rabbits are at risk. RVHD in particular is highly contagious. Not only can it be spread by direct rabbit to rabbit contact, it also can be spread by biting insects (as can Myxo) and by indirect contact with infected rabbits. For example - if you, your dog or cat has walked on ground where a RVHD infected rabbit has been, you can carry it on your clothes or shoes, your other pets can carry it on their fur or feet. The virus can survive in the environment for a long time throughout a range of temperatures. Fomites (inanimate objects) like food bowls, hutches and foraged plants can all potentially be contaminated and spread the virus to new areas and other rabbits. Thankfully the UK has had efficient vaccinations available for both RVHD1 and Myxomatosis for many years now. The current UK vaccine is the Nobivac Myxo - RHD, released in 2012, made by MSD Animal Health and just needs one simple injection every year to give the rabbit the best chance of protection. However, it is worth noting that no vaccine gives 100% immunity (even in human medicine), but it does mean that vaccinated rabbits at least have a chance of survival when given the appropriate supportive veterinary treatment.

So Whats Changed?

Sadly there are a few different strains of RVHD where the virus has mutated in slightly different ways and this means that the regular vaccination available in the UK is not guaranteed to cover the different strains. The UK now has BOTH the RVHD1 and the RVHD2 strain throughout the country, with hundreds of potential deaths so far and many of these confirmed via veterinary laboratories as RVHD2. These confirmed cases are not confined to one geographical location and are spread throughout the UK.

Although there are still many similarities, RVHD2 differs from the original RVHD1 virus in a few ways:

• It can affect rabbits of ANY age (even under 8 weeks)

• The mortality rate is more variable (but it is not yet fully understood as to why)

• It appears that RVHD2 doesnt kill as quickly - meaning that a rabbit may seem a bit unwell or have suspected stasis a few days before the death occurs

Many vets are unaware of the prevalence and severity of this new strain. Therefore owners and animal organisations become critical in helping to raise awareness of the issue by speaking to their local veterinary clinics.

Veterinary Information

Richard Saunders is the Veterinary advisor to The Rabbit Welfare Association and Fund. (RWAF) He has been working tirelessly since last year to gain as much knowledge and research into the new strain of the disease, the choices of vaccines that are currently available in Europe and risk analysis. He has also been pivotal in securing the Special Import License from the Veterinary Medicines Directorate for a range of different vaccines that have been proven as efficacious against RVHD2. He has also managed to get one of the UK's largest veterinary wholesalers, NVS, to stock the Filavac KC+V vaccine. This makes it very simple for vets to order in the product that has been successfully used in Europe for some time already. Subsequently, 2 more large wholesalers have also agreed to stock the vaccine - Centaur and Henry Schein. Sadly not all UK wholesalers are currently prepared to consider stocking any of the RVHD2 vaccines which will make it more difficult for some vets to acquire it, however there is a way for vets to order direct from the manufacturers if they cannot persuade their own supplier to stock it. Current stock levels are variable so its advisable that vets contact their suppliers as soon as possible to place their orders. See the RWAF's most recent update for more info. Please only contact the wholesalers if you are a veterinary professional - they cannot help or advise owners directly.

Vaccination Protocol

All rabbits should have a full veterinary health check before being given any vaccination.

• As previously discussed, the current Nobivac vaccine covers both Myxomatosis and RVHD1. It is vital that this continues to be given every year and can be administered to healthy rabbits from 5 weeks old and it takes up to 3 weeks after subcutaneous injection to reach optimum protection levels.

• The Filavac vaccine covers both RVHD1 and RVHD2 but does NOT cover Myxomatosis. It can be given to all healthy rabbits over 10 weeks old and it takes up to 7 days after subcutaneous injection to reach optimum protection levels. Vets with clients in high risk areas may choose to give the Filavac vaccine every 6 months, but in all other areas then the vaccination is only needed once per year

It is recommended that a gap of AT LEAST 2 weeks is left between giving each of these different vaccinations. There are no current studies that show how these two vaccines would interact however, the 2 week recommendation has been taken from the standard immunology advice guidelines. There are also no studies that definitively show what effects may happen from giving the RHVD1 vaccine twice - but the risks have been assessed by Richard Saunders and in his opinion, the benefits outweigh the potential risks.

It is vital to understand that the current Nobivac vaccine MUST still given to all healthy rabbits over 5 weeks old, every year, because the Filavac vaccine does NOT cover Myxomatosis.

Some vets may want to hold vaccination clinics where multiple rabbits are vaccinated within the space of a few hours. This is ok but do bear in mind that it may increase the risk of spreading disease and illness by having a collection of multiple rabbits from multiple locations all together in the same waiting room. It is not known how much of a risk this may cause but its just something to bear in mind.

Please watch this excellent webinar for more RVHD2 info.

Biosecurity

Due to the diverse way that RVHD can be spread, it is important that all owners, vets, breeders, pet shops and showers take as many biosecurity precautions as possible:

• Use quarantine and barrier nursing techniques. I personally would recommend that all new rabbits entering your home / work place are quarantined for at least 2 weeks. This will allow the rabbit to recover from the stress of the move as well as give time for some potential underlying health issues to present themselves. During this time, barrier nursing techniques are advised which means keeping the rabbit away from all other animals, using specific consumables (bowls, towels, food, foot baths and human clothing) for that particular rabbit that is kept inside the isolation area. This protocol should also be implemented for any sick rabbits that are suspected to have RVHD however as always - vet guidance should be sought immediately. In my opinion, existing bonded pairs should not be separated due to the excess stress it causes for each rabbit. If a suspected RVHD case (or even an illeus of unknown origin case) is hospitalized at a veterinary clinic then full isolation and barrier nursing procedures should be strongly considered as a precaution

• Use veterinary approved cleaners and disinfectants and know the difference between the two. Cleaning must take place before successful disinfection can happen. Steam cleaning is a good initial phase followed by one or more of the following examples ( not an exhaustive list):

1. F10scxd - this is a cleaner and a disinfectant
2. Ark-Klens - this is a cleaner and disinfectant
3. Virkon S - this is a broad spectrum veterinary disinfectant (and DEFRA approved)

• Be careful with fresh forage This may not be a huge risk but still a factor to consider. Make sure you only pick safe plants from areas with no wild rabbits around and wash them thoroughly before feeding. Ideally, grow your own forage plants in your home / garden / greenhouse or buy good quality, pre packaged, dried forage to minimize the risk.

• Avoid rabbit shows / pet shops / petting farms. As this disease can be spread via your shoes, clothes and hands, I strongly advise all owners to avoid anywhere that has significant numbers of rabbits. Often these places can contain non vaccinated rabbits and rarely have sufficient biosecurity in place. Even if you do not take your own rabbits along, you risk spreading or bringing home a deadly disease on your clothing, buggy wheels etc.

Sudden Deaths

If as an owner, you are in the terrible situation where one of your rabbits die suddenly with no clear explanation then please always take them to the vets. The true scale of the RVHD crisis is unknown and current numbers are suspected to be on the low side due to the fact that most sudden deaths are not reported to the vets and of the small percentage that are, even less are actually tested for RVHD. It is always heartbreaking to have to think about post mortems and liver testing at this sad time but it could save the lives of many other rabbits by helping us gain a better insight into the prevalence of this disease. You have 2 options:

1. A liver biopsy test. This is where the vet purely takes some samples from the liver and sends them to a laboratory (usually the Moredun in Scotland) specifically for RVHD testing. This is significantly cheaper than a full post mortem and the ONLY way that RVHD can actually be confirmed.
2. A full post mortem. This is where the vet will spend a significant amount of time examining many aspects of the rabbit and possibly send some samples to an external laboratory for tests. There is never a guarantee that a post mortem will give you a 100% cause of death and can be quite costly.

All post mortem tests need to be performed as soon as possible after the rabbit has died.

To prevent further possible contamination, please wrap the body in 2 layers of plastic and disinfect the outside layer. This can then be placed into a plastic box that can be fully cleaned and disinfected or a cardboard box that can be burnt after use. Also, in my opinion, it is safest to have your rabbit cremated rather than bury them at home as there is currently no definitive research to show if this may pose a further contamination risk (bearing in mind we do know that RVHD can live in the environment for many months).

Keeping Up To Date

The best way for everyone to keep up to date is by following the advice of the RWAF. This can be done in a few different ways:

• Veterinary professionals:

1. Email hq@rabbitwelfare.co.uk and ask to be added to the vet email list. This will inform you of the most current rabbit care information as it becomes available.
2. Join the RWAF as a vet member. This is a step further than the email list and gives you a host of extras including client brochures, quarterly magazines and discounts to great CPD.
3. Keep an eye out in the trade press for articles like this.
4. Follow the RVHD specific facebook group that is compiling as much factual information as possible as well as highlighting confirmed RVHD cases and veterinary clinics that currently have or will soon be having the Filavac vaccine in stock.

• Owners

1. Email hq@rabbitwelfare.co.uk and ask to be added to the 'first alert' email list. This will inform you of the most current rabbit care information as it becomes available
2. Join the RWAF as a member. This is a step further than the email list and gives you a host of extras including quarterly 'Rabbiting On' magazines, an 'on the hop' rabbit care brochure and a discount to the annual conference.
3. Follow the RVHD specific facebook group that is compiling as much factual information as possible as well as highlighting confirmed RVHD cases and veterinary clinics that currently have or will soon be having the Filavac vaccine in stock.
4. Follow a few blogs that are written by trusted sources.

• Alison's blog about her personal experiences as she struggles with losing rabbits to RVHD2

• My rabbit awareness blog which discusses all rabbit welfare matters including RVHD

• The RWAF official blog

All the views in this article are my own and the factual information and links are correct at the time of publishing.