Rabbit Haemorrhagic Disease 2 (RHD2)

Introduction to Rabbit Haemorrhagic Disease

Rabbit Haemorrhagic Disease Type 1 (RHD1) is a disease affecting rabbits first which was discovered in 1984 in China and causes sudden death in rabbits (Oryctolagus cuniculus).  RHD1 spread quickly but overtime was controlled by a combination of improved hygiene and a vaccination program, one which is still available today.

Fast forward until 2010, a new version of Rabbit Haemorrhagic Disease, this time Type 2 (AKA RHD2), appeared. By 2014 RHD2 had spread to the UK and from there it spread as far away as Canada and Australia.

Rabbit Haemorrhagic Disease Type 2

RHD2 affects European rabbits of all ages and, unlike type 1, also affects hares.  In 2015 it also started to really cause problems among shows, breeding colonies and in rescue centres where it spread quickly between animals sharing a small space and where rabbits were coming and going. The presence of it in shows also accelerated it’s spread across the UK.

Unlike RHD1, Type 2 can affect many species of rabbit/ hare

Rabbit Haemorrhagic Disease Type 1 tends to cause sudden death with nothing much else seen otherwise.  RHD2, however, only causes sudden death in a minority of cases, in fact only killing approximately 20% of affected rabbits (though it can kill as few as 5% up to as many as 70% dependent on the area and the timing). Instead, RHD2 often leads to a longer period of illness followed by a recovery.

Between a rabbit catching RHD2 and showing signs of illness there, is approximately 3-9days, known as the incubation period.  During this period, the rabbit can pass it to other rabbits without you even knowing they had it.  Therefore, RHD2 is often spread before you have the chance to improve or alter your cleaning practices and therefore you need to be prepared. It is important you improve your methods and act as if your animal may have it right now; clean their cages to the best of your ability all the time and, perhaps the best prevention, keep rabbits vaccinated against RHD2 to protect them from catching it.

The signs of RHD2

The virus can cause your rabbit to become ill in three different forms;

Percute type
  • This looks similar to RHVD1 in terms of it just leads to sudden death
Acute Type
  • Fatal in a lot of cases, often within the space of 36htrs.
  • Signs of it are
    • collapsing,
    • large amount of bleeding; blood in their urine, any discharge from their body, bleeding gums and nosebleeds.
    • Some show signs of brain and nerve problems
    • collapse,
    • seizuring,
    • poor balance,
    • falling over, or,
    • walking like they are drunk (Ataxia).
    • crying out a lot.
Subacute/ Chronic Form
  • This sometimes causes rabbis to die but often not for over a week and is due to liver failure, the main organ affected by RHD.
  • During this time they have
    • severe jaundice (meaning their skin and the white of their eyes, along with other places, looks yellow),
    • they refuse to eat
    • very quiet
    • lethargic.

Treatment

Firstly if you suspect one of your rabbits has RHD2 it is important for you to contact your vet straight away.

When rabbits have Subacute/ Chronic RHD2 they often stop eating and drinking. To prevent rabbits becoming dehydrated, make them feel better and increase their odds of survival you should make sure they’re kept warm (be careful using heat pads or hot water bottles; these can burn their sensitive skin. Only use heat pads if they are no warmer than around 40C and they are able to move away from them on their own). If they are very unwell or not drinking your vet may want to put them on a drip until they are drinking and eating enough.

How it’s Spread

RHD2 is highly contagious meaning it can spread from one rabbit to another very easily.

However, it’s not just rabbits you have to make sure don’t pass it on, if any of the virus gets on the bowls, cages, your shoes etc, anything another rabbit may come into contact with it can be passed along.

The main things the virus is passed on in is the tears, saliva and nasal discharge but it also stays in and on any of the rabbit’s bodies who died from it.

Indoor rabbits may be affected by RHD2 too. Image; Twitter @SarahTait123

To make it worse and even less predictable, if a fly has been near an infected rabbit they can pass it to another rabbit they spend time near/ bite.

Finally, RHD2 is spread in the rabbits urine and faeces throughout the whole time they are infected until around one-two days after the infection has resolved.  The risk is if one cage is stacked on top of another then it could be spread easily if they are not completely waterproof and any urine seaps from one cage into another, infecting the second group of rabbits.

It is unknown how long the virus survives to reinfect other rabbits when it’s in the environment.  One thing to watch out for is later infections if a previous rabbit had one such as a rabbit catching it from bits of virus left in its cage.

Therefore, if you are keeping rabbits near/ in an area where a rabbit has been previously infected with RHD2 it is important you keep up with high levels of hygiene, vaccinate all of the rabbits and be vigilant for signs of infection.

If your rabbits have previously had it or you own a breeding colony/ similar leaving rabbits your rabbits are at high risk of getting it.

Preventing the Spread of RHD2

If you have several rabbits and one has come down with RHD2 you should isolate the affected one and look after that one totally separately. Your hands should be thoroughly cleaned and/ or alcohol rub used to clean your hands and you should wear different clothes when looking after/ interacting with your healthy rabbits to try and prevent its spread.

RHD2 is a very difficult virus to kill and prevent its spread so often doing this isn’t 100% effective especially with rabbits spreading the disease before they show any signs of illness.

One any affected rabbits have been separated from the healthy ones it is important you get the healthy rabbits vaccinated against RHVD2.  A vaccine for type 1 has been shown to now really help against type 2 (though in some cases may offer a small amount of protection). Your rabbits will then need to get boosters at least every year, ideally every six months if your rabbits are at a higher risk of catching it such as you show or breed them or you’ve owned affected rabbits near where your current rabbits are housed.

Really young rabbits are at risk of RHD2 and, in high risk areas, vaccinating them at four weeks old should be considered

With the disease spreading very easily and being difficult not only to save rabbits but to prevent others from becoming infected, rabbit shows are now cancelled in an affected area. You should not take a rabbit to a show if you suspect they are infected or if you have another rabbit who has it or recently did.

To prevent RHD2 from spreading you should use plenty of good quality disinfectants when cleaning their cage and anything they come into contact with. Sadly, the RHD2 virus is difficult to kill so not all disinfectants are effective.  The use of alcohol skin rubs rather than a disinfectant called Chlorhexidine (either within a rub or as a soap with water) is more effective.  Other than that, when cleaning their cages diluted household bleach may be one of the most reliable things. If you use bleach make sure the cage is thoroughly rinsed out afterwards to prevent it burning your rabbits skin or the inside their mouth if they gnaw on a treated area.

 

Vaccination

For rabbits at high risk, it is worthwhile considering vaccinating kits from four weeks old.  Prior to this age if their mother has either had RHV2 or has been exposed to it the kits will get immunity from their mother’s milk, however, this immunity wears off at four weeks.

At four weeks old these rabbits no longer are protected by their mother and are very susceptible to it due to their underdeveloped immune system. If they’re not vaccinated at four weeks and are exposed to RHD2 they will likely get it.  Current vaccines have a licence to be used from 10weeks of age but are believed to be safe to use from four weeks of age.  However, if given the vaccine at four weeks old, young rabbits will need a second vaccination when they are ten weeks old as it hasn’t been shown to last longer than this 8n such young rabbits.

It is still important they have vaccines against myxomatosis which, itself, is often lethal

Vaccinations, once given at ten weeks of age or older last for a year in mild-moderate risk areas.  However, if your rabbits are at high risk of an infection it is recommended they have a booster every six months.

RHD2 vaccines are on top of Myxo-RHD1 vaccinations which are the normal vaccines given annually in the UK against myxomatosis and RHD1.  This vaccine is very important for rabbits to still get as RHD2 vaccines do not work against myxomatosis or RHD1 and vice versa. Myxomatosis in its own right is a very common and often fatal disease which can be easily prevented by annual boosters s9 these should be unavoided as other methods o& prevention are less effective.

Currently, there is no evidence of whether the Myxo-RHD and the RHD2 vaccines interfere with each other if given at the same time and, therefore, it is recommended that at least two weeks is given between a vet giving your rabbit each of these vaccines. Though, it doesn’t matter if the vaccines are separated by a longer period of time, or which is given first.

The new vaccine in the UK by Filavacs however, does cover both types of RHVD. However, it must be remembered that this vaccination still doesn’t cover myxomatosis at all so getting that vaccine too is still highly recommended.

In Summary

There are two types of Rabbit Haemorrhagic Disease; type one tends to cause sudden death. Type two however can cause a more long-lasting disease.

Both types can be prevented by vaccination and Filavacs does a vaccine protecting against both but rabbits should also be vaccinated against Myxomatosis in a separate vaccine.

Rabbits at high risk should be vaccinated from very young (4weeks of age) and maybe twice a year as well as thorough cleaning and prevention strategies.  Shows should be avoided in high risk areas too.

If you believe your rabbit may have RHD then contact your vet immediately.

 

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Author: Kim Halford

I'm a qualified vet and animal behaviour and welfare advisor. I am dedicated to improving the welfare of animals. I also want to work with organisations to improve the education of animal welfare and behaviour as well as improve the bond between animal and owner.

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