What is rabbit haemorrhagic disease (RHD)?
Rabbit haemorrhagic disease (RHD) is a highly infectious, serious viral illness which is usually rapidly fatal in unvaccinated rabbits.
Rabbit haemorrhagic disease is caused by two strains of the Rabbit Haemorrhagic Disease virus: RHDV 1, which is highly host-specific, meaning that it only affects European rabbits, from which the UK’s domestic rabbits are descended; and RHDV 2, which affects European rabbits and can also affect hare species.
RHD1 is extremely dangerous and highly infectious, with a death rate of around 90% for unvaccinated rabbits. RVHD1 leads to blood clots in an infected rabbit’s lungs, liver, kidneys and heart. The clots can lead to catastrophic internal bleeding due to blood vessels rupturing.
With RHD1 most rabbits usually die within 2-4 days, and death can be sudden. Sometimes there are no obvious or visible symptoms, but some rabbits may be lethargic or have a fever; rapid respiratory rate; and bleeding around the mouth, nose and anus.
First identified in the UK in 2013, RHD2 is a mutation of RHD1 and is considered a new strain. Studies suggest it may have been present in the UK since before 2013.
While the death rate for RVHD2 is lower (typically peaking at around 70%), it is more likely to be contagious due to a longer incubation period, which can last from about 3 to 9 days. RHD2 can affect very young rabbits and baby rabbits under 4 weeks old.
What are the symptoms of rabbit haemorrhagic disease?
The clinical signs and symptoms of rabbit haemorrhagic disease can vary case by case in infected rabbits, depending on the strain of virus and how quickly the signs of this highly contagious disease develop.
Some rabbits are sadly found dead without having shown signs prior to death. This is more often the case with the RHDV1 strain of the virus, which can cause sudden death.
In the acute form of the disease, the infected rabbit may become reluctant to move, develop a high fever and have an increased heart rate and respiratory signs of distress (such as rapid breathing).
Bloody nasal discharge may be seen, and bleeding can also sometimes occur around the mouth or genital area. Infected rabbits may suffer from seizures before sudden death, which generally occurs within 12-36 hours from the onset of symptoms.
Chronic rabbit haemorrhagic disease tends to last for longer and is most often seen with RHDV2 infections. The symptoms for infected rabbits may include lethargy (extreme tiredness or reluctance to move), loss of appetite, weight loss and jaundice (yellowing of the gums, conjunctiva and whites of the eyes).
Heart, gut and brain abnormalities may also be seen. Some rabbits may survive the chronic form of the disease, but death is usually caused by liver failure, 1-2 weeks after the onset of symptoms.
A small number of rabbits that contract the virus do recover without developing signs of the disease. Some of these may become carriers of the virus, showing no signs of the disease, but shedding the virus and infecting other animals.
Is rabbit haemorrhagic disease contagious?
The RHD virus is highly infectious and extremely contagious to other rabbits, and can cause sudden death. It cannot be caught by humans, cats, dogs or other pets.
Rabbit haemorrhagic disease can spread by:
- Direct contact with infected animals, body fluids and hair. Surviving rabbits can be contagious for up to two months
- Contaminated clothing, bedding, food, cages and water can spread the virus
- Flies, fleas and mosquitos can carry the virus between rabbits
- Predators can spread the virus by shedding it in their faeces after eating infected rabbits
What happens if my rabbit is a house rabbit?
While the risk of catching viral haemorrhagic disease is lower for domestic, indoor or house rabbits, it’s still never zero. Indoor rabbits are naturally at a lower risk due to less contact with contaminants and other infected animals, however it’s still vital to take necessary precautions against RHD1 and RHD2. It’s important to make sure your rabbit has up to date vaccinations and jabs, and also avoid any contact with other rabbits who may have been infected – including their bedding, food and water. Similarly, fleas can also carry the virus, so making sure any pest-repellant treatment is up to date is a good way to take precautions against rabbit haemorrhagic disease.
Rabbit haemorrhagic disease treatment
Sadly, there is no cure for an RHD infected rabbit. It is often kindest to humanely put to sleep affected rabbits. If rabbits are not severely affected and treatment is attempted, strict quarantine away from other rabbits is needed. They can then be given generalised supportive care (fluid therapy, syringe feeding, warmth) whilst their immune system fights the virus.
Prevention and control for rabbit haemorrhagic disease
Prevention and control are key in protecting domestic and wild rabbits from this highly contagious disease.
Rabbits should be vaccinated yearly to prevent any outbreaks or infections. Vaccination is available at your local Animal Trust surgery for £47.50. The vaccine used (Nobivac Myxo-RHD PLUS) protects your pet rabbit from both strains of the rabbit haemorrhagic disease virus after a single dose. This vaccine can be given any time from 5 weeks of age and provides protection against RHDV and also myxomatosis for 12 months.
If you lose one or more of your pet rabbits to rabbit haemorrhagic disease, any new domestic rabbits must be fully vaccinated at least 3 weeks before introducing them into the area or to any surviving rabbits. This is because the incubation period means the virus may survive in the environment for months, and surviving rabbits may shed the virus if they become a carrier.
Cleaning and control
Control of infection involves disposal of the enclosure, bedding, and any other items which have been in contact with any rabbits infected with the virus. Disinfection of all remaining surfaces using 10% bleach solution or other effective cleaners such as Virkon, Anigene (full list available on Environmental Protection Agency’s website) is essential.
Keeping your rabbits’ housing and environment clean will prevent attracting flies. Any rabbits at risk of fleas (from cats, dogs and wild animals) should be regularly treated to prevent infestation. Ask your local Animal Trust clinic for specific advice for your pet rabbit.
Pest and parasite prevention
RHD can be spred through insects and pets. Where possible, try to keep rabbits inside during the damp and warm months – this is when fleas and other insects like mosquitoes tend to thrive.
You can also use vet-approved parasite control and flea treatments for rabbits – ask at your local Animal Trust clinic for advice.
If you do have any new rabbits join your household, to prevent any transmission of RHD they should be quarantined away from any existing rabbits for a period of three weeks at least. They should also be vaccinated if they’re not currently up to date.
If your rabbits have been exposed to RHD or have suffered an outbreak of RHD2, for example, it’s vital to quarantine them before introducing any new pets. Typically, in addition to through cleaning and disposal of any potentially contaminated items, we would recommend a period of at least 3-4 months before considering introducing any new rabbits. However, it’s important to remember that vaccinations are not 100% effective and the risk of infection needs to be constantly considered.
Avoiding contact between your domestic rabbit and any wild rabbits is key to preventing the spread of RHD.
Rabbit proofing your garden to reduce exposure of pet rabbits to wild rabbits which may carry the virus is a helpful additional measure to protect your furry friend. Using wire and panels to board up fences, and making sure to keep an eye on any holes or potential tunnels through flower beds or under fences is an important step.
If you’re worried about keeping your pet safe from the rabbit haemorrhagic disease virus, get in touch with your local Animal Trust team for advice and support.