Is This Rabbit Disease In Your Area? Let’s Talk About RHD2 HV

After recently losing a vaccinated rabbit to viral haemorrhagic disease, I stumbled across a page on the Rabbit Welfare Association website with information about a new and more virulent strain of RHD2 that is currently rampaging across Europe. And for which pharmaceutical company HIPRA have already developed a vaccine. 

If any of your rabbits have been affected by RHD my heart goes out to you. This is a truly horrible disease. And in scouring the internet for information (about the new strain and about the new vaccine) I discovered there isn’t very much of it.  

Indeed, much of the existing information available on RHD2 even on reputable websites such as the Royal Veterinary College is out of date. And much of it is confusing. So I’m going to use this page to record new information as I find it, both for my own benefit and yours. And I’ll start with a brief summary of what RHD is and what we, as rabbit keepers, can do about it. 

You’ll find links to my sources, and to organisations that seem to be keeping up with the situation, at the end of the article.

Of course none of this information constitutes veterinary advice, and you should always contact a qualified veterinarian if your rabbit seems unwell or you have any concerns or questions about vaccination. 

What is RHD?

You’ll see various acronyms for Rabbit Viral Haemorraghic Disease:  RHDV, RVHD, VHD, RHD and sometimes RHVD. In the context of rabbits, these all refer to the same viral disease which causes death through catastrophic internal bleeding and organ failure. You’ll find that people sometimes refer to it as ‘rabbit ebola’. Though the virus acts so quickly that very often the only symptom is a dead rabbit. 

It isn’t just all those acronyms that are confusing. The ‘strains’ of the virus are confusing too. 

There are two main versions of the disease, RHD1 and RHD2. And they have slightly different incubation times and mortality rates. A few sources are referring to the new (in 2024) highly virulent strain of RHD2 when they talk about the ‘new strain’. While most sources using the term ‘new strain’ are referring to the emergence of RHD2 in 2010

So let’s be clear. It would appear that right now, there are four fatal diseases that can affect domestic rabbits in Europe and for which we now have vaccines. 

1. Myxomatosis
2. RHD1 (emerged in 1980s)
3. RHD2 original (emerged in 2010)
4. RHD2 highly virulent strain (emerged in 2024)

I won’t talk about myxomatosis here, it’s a very different disease and a topic of its own. Let’s look at those three varieties or strains of RHD

RHD1 – the first rabbit hemorrhagic disease

RHD1 was our first encounter with viral hemorrhagic disease in rabbits. It made its first appearance in China in the 1980s. The disease quickly reached Europe where it decimated the wild rabbit population just as it was recovering from decades of myxomatosis. 

Rabbits can infect one another, but they can also be infected by biting insects and even by casual contact with the virus on surfaces. The virus is extremely tough and can live outside of the rabbit for months at a time, surviving freezing winters and high temperatures. 

Incubation time is short, up to three days and sometimes less than 24 hours, and with the exception of rabbits under ten weeks old, the disease kills almost every rabbit that is unfortunate enough to cross its path. This original disease mutated to create RHD2

RHD2 – less virulent strain

The second main strain of RHD appeared in Europe in 2010 and rapidly took over as the dominant disease in Europe. The main difference from RHD1 is the ability of RHD2 to kill much younger baby rabbits. The incubation time is a little longer 3-9 days and the disease has a slightly lower mortality rate. But only slightly. 

The bottom line is, If your unvaccinated rabbit gets this virus they will probably die. And you won’t get much warning.

RHD2 – high virulence strain

The Rabbit Welfare Association are referring to this new highly virulent strain of RHD2 as RHD2 HV.  This helps to differentiate it from the RHD2 strain that took over as the dominant strain in 2010.  

RHD2 HV emerged in 2024 and now accounts for half of all cases in France.  As France is our next door neighbour and only 20 miles or so of water separates us, it is likely that the disease has reached or is about to reach, the UK. 

The good news is that there is already an effective and very reasonably priced vaccine. The bad news is that British suppliers have run out of those stocks.  I contacted the vaccine manufacturer HIPRA who were very helpful and are trying to catch up with demand.  They hope to be able to ship to the UK by the end of February 2025. 

Should you vaccinate your rabbit?

Yes!  If you are in a region where RHD exists your rabbit is extremely vulnerable. Most months I see people posting on rabbit forums asking “why are my rabbits dying?” and RHD is usually the culprit. 

At the moment the disease kills almost all rabbits that catch it, and vaccination is the only protection you have. Most of the reports of rabbits dying after vaccination are where there has already been a rabbit death in the family and the rabbit owners rush to vaccinate the other rabbits. Unfortunately this is usually too late. Antibodies take time to build up and don’t peak for several weeks after vaccination. So don’t wait for a rabbit to die. 

What about the USA?

The disease has taken longer to get established in the USA but it is now spreading there too. Scattered reports of RHDV2 in domestic rabbits in North America date back to 2016 and by 2020 the disease was becoming established in Western USA. It is currently making its way eastwards across the continent. https://rhdv2.org  

America has been somewhat slow to licence a vaccine against RHD but there is now one available, so do talk to your veterinarian about protecting your rabbits.

My experience of RHD2

My first experience with RHD involved the complete loss of the first litter of 9 week old baby rabbits that I bred on our homestead. The disease took them with frightening speed, one after another at intervals of just a few hours, and coincided with a flush of mosquitos hatching in April. The fault was mine as these babies were unvaccinated, but I had thought we were safe from disease as there were no wild rabbits on our property or nearby.  

At this time my adult rabbits lived indoors and they all survived. After the deaths of these two litters, I then set about establishing a vaccination protocol for my breeding stock and keeping my unvaccinated kits indoors. 

My most recent outbreak was different. It started with a healthy vaccinated young adult rabbit living in an outdoor colony. She was hopping about and grazing in the evening, and dead by the following lunch time. She looked in perfect condition. The only clue to the cause of her demise was a tiny drop of blood on the underside of her tail. Post mortem examination revealed massive internal haemorraging.

Why did my vaccinated rabbit die?

There are three possibilities 

• She didn’t have RHD and died from something else
• Her vaccination failed to work
• She was exposed to a new strain of RHD not covered by the vaccine 

#1 Did my rabbit die from something else?

Sudden death in a rabbit that was apparently healthy just hours before is often an indicator of VHD. When this is accompanied by bleeding from the mouth, nose, or bottom then VHD is almost always the culprit, and a post mortem finding of massive internal haemorrage makes VHD pretty much a certainty.

The history of previous cases on the homestead supports this argument. 

Of course a lab test to confirm the presence of the virus would be the definitive way to confirm diagnosis, but it isn’t necessary as there really isn’t anything else that could have caused my first rabbit to die so quickly in this manner. Followed six days later by the second. 

#2 What about Vaccine Failure

Vaccines are amazing, but they are not perfect. There is a failure rate and if you vaccinate enough rabbits, in an area with a known disease risk, then sooner or later a vaccinated rabbit is going to get sick and die. 

In addition, there is the potential for operator error. I could have made a mistake when I vaccinated her, perhaps failing to inject enough vaccine for example.

My initial hope was that this is what had happened. 

#3 The New High Virulence Strain Of RHD

When the second rabbit died, this made the existence of the new strain RHD2 HV a more likely culprit. Especially as the second rabbit was vaccinated only five months previously. 

Highly virulent means a higher mortality rate. It also meant a strong possibility that my outdoor colony of rabbits were completely unprotected by their current vaccinations. 

This is bad news for my rabbits, but it’s also bad news for rabbits throughout the UK as their current vaccine may no longer be offering protection. 

What can rabbit keepers do? 

Talk to your vet first and foremost and take their advice. But also let them know what you now know! 

A vet just a few miles from me in one direction hadn’t yet heard of the virulent strain or of the new Yurvac RHD vaccine. While a vet a few miles in another direction is offering a clinic to mass vaccinate their rabbit patients with the new vaccine.

The fact is, few vets specialize in rabbits and some are still unaware of the new RHD2 HV strain or that there is a vaccine for it. 

Do your research before attending one of the vaccination clinics and talk to the vet about the precautions they are taking to prevent cross contamination between rabbits from different households. The Rabbit Welfare Association caution against these clinics due to the challenges involved.

Unfortunately the vaccine manufacturers are only currently supplying 40 doses in a single phial. Which makes it difficult for vets to offer a cost effective vaccination to individual rabbits. So depending on your circumstances at home, attending a clinic may be your best option. Again, talk to your vet. 

Share your knowledge

And tell your vet what you have learned. Rabbit keepers are an important source of information and knowledge. We need to spread the word about suspicions of new emerging diseases or vaccine resistance strains of existing diseases so that these can be caught and tracked as soon as possible. 

Wherever you live, let your vet vaccinate your rabbits with what’s available to protect them against RHD. Don’t wait for one to get sick. I know these vaccines can be expensive, but RHD kills without warning, causes great suffering, and there is no effective treatment. 

Consider moving rabbits indoors

Finally a word about outdoor rabbits. If you are in Europe, where possible, it might be sensible to bring outdoor rabbits indoors until they are protected with the new vaccine that protects against RHD2 HV.  Being indoors doesn’t offer complete protection but it does reduce your rabbits’ exposure to flying insects etc. 

What can vets do?

The Rabbit Welfare Association provides information for veterinary professionals And urges you to report cases, where a patient of yours acquires, or dies from, suspected RVHD after vaccination, to the vaccine manufacturers MSD and/or Hipra directly,  or email [email protected]

You can find information on the Yurvac vaccine here: Yurvac Product Info From Defra  

Does  Nobivac Myxo plus still work?

Here in the UK we have been fortunate to have a vaccine that covers both original strains of RHD and myxomatosis

Some of the sources reporting on this new virulent strain of RHD2 are claiming that the current Nobivac virus does not protect against it.  But I cannot find any studies to support this. And I suspect that what they actually mean is that we don’t know if the Nobivac vaccine works on this new strain. 

However, the new Yurvac RHD vaccine does offer protection, but only against RHD and not against myxomatosis, which is why the Rabbit Welfare Association is recommending both vaccines be given, with at least two weeks between them.   

Finding more information

Do check the date of any sources you visit on RHD. Surprisingly, many sources fail to put a publishing date on their RHD information. This is a worry because medical information can change rapidly over time. 

Many reports on the new strain of rabbit disease turn out to be about the emergence of RHD2  a decade ago when the dominant disease was still RHD1 With a lack of dates on published articles this outdated content isn’t always easy to identify. 

The Rabbit Welfare Association have information about the RHD2 HV for the public on this page. And for veterinary professionals on this page dated 17th December 2024.  They also have a Facebook Group for veterinary professionals.

The British Rabbit Council have published the statement below.  Unfortunately this information  does not have a date but it looks fairly recent.

Urgent Statement from the Health and Welfare Committee of The British Rabbit Council:
We have been informed that there is a new virulent form of RHD2 in Western Europe. Cases have been confirmed in France, Hungary, The Netherlands and Northern Italy.
A new vaccine, effective against RHD1 and both varieties of RHD2 is already available in Europe and has now been approved  by the UK vet medicine directorate and will be available within the next few weeks. It has been developed by HIPRA and replaces Eravac, which is no longer in production.  The trade name for the new vaccine is Yurvac RHD.
We would urge any exhibitor importing from Europe before the new vaccine is available to ensure that a strict 2 week quarantine be observed. This will help to protect both your and other people’s stock.  We will let you know as soon as we hear that the vaccine is in stock with wholesalers in this country.  We suspect that the advice will be to vaccinate all stock with the new vaccine where possible. British vets will be unlikely to take orders until the vaccine is with the wholesalers.
Any members using Nobivac myxo-RHD should be aware that their stock are NOT covered against the RHD2 new virulent strain.
We will share further information as soon as we have any.

For the scientists among you, the World Organisation For Animal Health have an interesting pdf on RHD which goes into a great deal of detail on the biology and chemistry of this disease

Rabbits matter

My final thoughts on this today are that up to date information about RHD and emerging new strains matters. It matters because Rabbit Haemorrhagic Disease is a truly horrible illness caused by a virus that kills almost every unvaccinated domestic rabbit that comes into contact with it. 

Like most viruses it has the power to mutate and therefore the ability to reinvent itself with alarming regularity. And each time a new strain arises, that new strain may be resistant to existing vaccines. 

I feel that rabbits get a raw deal in some ways, despite being the third most popular pet in the world and a hugely important source of food in many countries, there are countries set on eradicating them by deliberately introducing diseases to the wild population, while husbandry standards in other countries are often very poor.

If this were a dog disease I can’t help thinking that the press and the RCVS would be all over it with information and updates. 

There is of course a commercial incentive for pharmaceutical companies to act swiftly. So I am hopeful that the providers of Nobivac will quickly modify their triple vaccine to include protection against the new virus. And I will update this article with new information as I have it. 

Meanwhile, I hope your rabbits stay safe!