Rabbit Hemorrhagic Disease (RHD)

Chinese Disease, RHD (Rabbit Hemorrhagic Disease), RHD2

One of the most dangerous diseases affecting rabbits is the RHD virus, which causes (often sudden) death in nearly 100% of infected rabbits. Only a few unvaccinated rabbits survive the disease.

The Virus

The RHD pathogen is a calicivirus, similar to one of the pathogens that cause feline respiratory disease. Interestingly, the virus originally comes from Germany, where it was first detected in Angora rabbits that were exported from Germany to China. For many years, only the classic RHD virus was prevalent, but in 2010, a new RHD strain (RHD2 virus) was first identified in France. This new strain also caused the death of vaccinated rabbits. In 2014, the RHD2 virus was detected in Germany for the first time, particularly in states bordering France.

The virus can survive without a host for up to seven months under favorable conditions. It is resistant to all weather influences, surviving for two days at sustained temperatures of 80°C (176°F) and up to 14 weeks at room temperature (20°C or 68°F).

Unlike the original strain, the RHD2 virus occurs not only in the summer months but also, unfortunately, with greater intensity in the autumn and winter.

RHD is no longer a notifiable disease and does not need to be reported.

Transmission & Risk of Infection

The virus is transmitted through direct contact with infected animals or indirectly via mosquitoes (RHD-1 and RHD-2) and flies (RHD-2 only). It can also be spread, though rarely, by rabbit fleas, mites, ticks, and other insects. Other transmission pathways include visits to the veterinarian, contaminated objects (such as shoes, clothing, or equipment), other animals (birds, rodents, etc.), or contaminated food (especially fresh greens from areas with infected wild rabbits or hares, as well as packaged hay or supermarket vegetables). Some surviving rabbits, which appear to be healthy again, can continue shedding the virus (chronic carriers).

If deceased rabbits are buried, the virus can survive for decades due to favorable conditions underground. The virus affects both domestic rabbits (including wild rabbits) and hares (European hares). Humans and other animals (including rodents and guinea pigs) cannot be infected by the virus—they are immune.

The incubation period from infection to the onset of symptoms is typically only one to three days. However, with RHD, deaths may still occur up to three weeks after the initial infection.

The primary victims are young and adult rabbits that have not been vaccinated against RHD1 and RHD2 (vaccines include Filavac or Eravac). RHD-1 primarily affects young rabbits over 10 weeks old, while RHD-2 can also infect younger rabbits.

Symptoms: How to Recognize RHD

The first noticeable signs are often suddenly deceased rabbits that were previously healthy and active. This is frequently followed by a mass die-off within the group over the course of several days. These rabbits may not display significant symptoms beforehand. However, shortly before death, they often develop a high fever or hypothermia, become lethargic, stop eating, struggle to breathe, and may experience seizures.

Bleeding from body openings is common with RHD1 but less so with RHD2. Other possible symptoms include diarrhea, yellowing of the mucous membranes, and neurological issues. Typically, affected rabbits succumb to the virus 12 to 36 hours after developing a fever (>40°C).

RHD2 often progresses less abruptly; infected rabbits first become apathetic and then die within hours following severe convulsions, typically without visible bleeding. Rabbits that appeared healthy may suddenly be found dead, often with their heads arched backward (a sign of air hunger).

Depending on the rabbit’s health, immune response, vaccination status, and age, 80 to 100% of infected rabbits or individuals die during an outbreak, even in vaccinated populations.

In addition to the acute form, RHD1 can also present in weaker, less acute forms, although this is rare. In these cases, rabbits may show symptoms such as apathy, fever, and poor or no appetite about two weeks after infection. These rabbits have a significantly higher chance of survival.

Treatment: Immediate Measures if Rabbits Are Affected

Whether an RHD outbreak is suspected due to the sudden death of one or more rabbits or has been confirmed, follow these steps to protect the remaining animals:

1. Relocate Surviving Rabbits
Move any surviving rabbits to a completely new, uncontaminated location, such as indoor cages, to reduce the risk of further exposure to the virus.

2. Strict Hygiene and Disinfection
Practice extreme hygiene measures before and after handling each rabbit and between handling multiple rabbits. The virus can also be transmitted by humans, objects, and clothing!

3. Only use fully virucidal disinfectants. Regular disinfectants are ineffective! (See below for specific recommendations on disinfectants.)
Plasma Treatment
Attempt treatment with blood plasma from a vaccinated rabbit (donor animal) if possible.

4. Liver-Supporting Supplements
Administer liver-supporting preparations to help the rabbit recover.

5. Antiviral Nutritional Support
Offer antiviral foods such as grated horseradish mixed with apple or mashed banana (start with small amounts and gradually increase, as rabbits may initially reject the mixture). Horseradish is known for its antiviral properties. Other effective options include Angocin (remove the protective coating so it is eaten), nasturtium, radishes, radish leaves, and other mustard plants.

6. Protection Against Mosquitoes
Install fly screens to protect rabbits from mosquitoes and check their food to eliminate potential sources of infection.

7. Intensive Medical Care
Rabbits showing early symptoms should receive intensive medical care, including:

8. IV fluids to strengthen and stabilize them
Assisted feeding if they refuse to eat
Painkillers and anti-bloating medications
Temperature control and stabilization (antipyretics for fever or warming for hypothermia)
Antibiotics to prevent secondary infections (note that antibiotics do not treat viruses or RHD directly)

9. Euthanasia
Rabbits in severe respiratory distress or experiencing prolonged suffering should be humanely euthanized to spare them from a painful death by asphyxiation.

10. Disposal of Deceased Rabbits
Do not bury deceased rabbits in the garden under any circumstances. They must be incinerated without exception, as decomposing carcasses provide ideal conditions for the virus to survive for years.

11. Handling Survivors
Follow specific protocols for managing surviving rabbits, as detailed in a dedicated section. Survivors may remain carriers of the virus and require careful management.

Deceased Rabbits
Under no circumstances should deceased rabbits be buried in the garden. They must be incinerated without exception! In decomposing carcasses, the virus finds optimal conditions and can survive for years.

Diagnosis: Was it really RHD(2)?

To confirm whether the rabbits truly died from RHD(2) and to better protect any remaining animals, a veterinarian can perform an autopsy and send samples for analysis. The veterinarian may inform you where the rabbit can be autopsied or send it in themselves. Fresh liver samples can also be sent directly to laboratories for testing to detect RHD1 and RHD2.

Possible Detection Methods

• Liver: Electron microscopy or PCR (direct pathogen detection) from the deceased rabbit or by fine needle aspiration from a living rabbit. Note: A positive result may occur up to four weeks after vaccination.

• Blood: EDTA blood samples. Note: Can only be detected during viremia (active infection) and may be positive up to four weeks after vaccination.

• Antibody Detection: Earliest two weeks after infection. This method is only useful for unvaccinated animals, as it cannot distinguish between vaccination and infection. Currently, antibody testing is poorly available in Germany.

Surviving Rabbits

It is crucial to vaccinate surviving rabbits as quickly as possible with a specific RHD2 vaccine (Filavac or Eravac), as vaccines like Nobivac Myxo-RHD Plus take too long to provide adequate protection. This is important because there is a risk of re-infection, such as from the fur of other surviving rabbits, contaminated objects, or the original source of infection.

Keep in mind that even after recovery, surviving rabbits can still be contagious for some time, as they may continue to shed the virus. This shedding can last for several weeks or even months. It is recommended to refrain from introducing new rabbits for at least eight weeks. During this time, the surviving rabbits should either be kept alone or with other survivors.

RHD2 can be detected in the urine and blood of living rabbits, but it is only shed intermittently. This means that even if no virus is detected during testing, the rabbit may still be shedding the virus. Multiple tests increase reliability. It is better to have deceased rabbits autopsied to confirm the cause of death.

After the waiting period, new rabbits can be introduced, but they should also be vaccinated with an RHD and RHD2 vaccine (YURVAC, Nobivac Plus, or Filavac) to ensure they are properly immunized.

Vaccinated Rabbits Dying?

Vaccines never provide 100% protection, and typically, the protection rate is around 98%. Deaths in vaccinated rabbits are extremely rare.

Possible Reasons:

• Weakened Immune System at the Time of Vaccination:
  Rabbits with a weakened immune system at the time of vaccination may not develop sufficient protection. In such cases, a second vaccination after a few weeks (to complete the initial immunization) and semi-annual boosters are recommended. This also applies to rabbits suffering from heavy parasite infestations (fecal test!), hidden illnesses, or those testing positive for E. Cuniculi.

• Break in the Cold Chain:
  If the vaccine was exposed to improper storage temperatures (break in the cold chain), it may lose its effectiveness.

• Expiration Date of the Vaccine:
  Ensure that the vaccine used was still within its expiration date. The expiration date is listed on the vaccine sticker in the vaccination record.

• 50-Dose Pack:
  If a 50-dose vial was used, it is important to adhere to the time frame specified in the product insert (for Filavac, this is 2 hours). You can verify whether a 50-dose vial was used by checking the entry in the vaccination record (sticker = single-dose vaccine, written entry = 50-dose vial). If the vaccine is administered after the 2-hour window, its effectiveness may no longer be guaranteed, even if the vaccine is taken under sterile conditions. Veterinarians offering this practice at unusually low prices may be a red flag.

• New Strain from France:
  There is a new strain of RHD2 from France, which appears to be less responsive to our current RHDv-2 vaccines. If vaccinated rabbits still die from RHD2, the variant should be further investigated

Disinfection after RHD

According to the German Veterinary Medical Society, the following disinfectants (listed in column 7a) are effective for disinfection against non-enveloped viruses (virucidal action):

• Halamid (3%): Can be used with a 2-hour exposure time.

• Rhodasept (2%): Effective with a 30-minute exposure time.

• Meliseptol Rapid V: Suitable for disinfection.

• Peracetic acid: Recommended for disinfecting wood items and shelters.

• Fully virucidal laundry detergent: Use approximately 4 tablespoons per machine at 60°C, depending on water hardness. Ideal for textiles, carpets, and clothing.

• Sterillium Vorugard or high-concentration alcohol: For hand and skin disinfection.

• Ensure the correct exposure times and concentrations are followed to ensure thorough disinfection.

Disinfection after RHD (Continued)

In most cases, disinfection is only possible on washable items. Other equipment and shelters may need to be disposed of or replaced. Alternatively, peracetic acid can be used, as it breaks down into harmless components and can disinfect shelters, wood, etc., although it is usually quite expensive. After disinfection, it is advisable to leave the enclosure empty for a period of time.

Washable textiles, such as carpets or clothing, should ideally be discarded. However, they can also be washed using a special fully virucidal laundry detergent (approximately 4 tablespoons per machine, depending on water hardness, at 60°C).

For soil, at least 30 cm should be removed. Afterward, paving stones can be laid down, and boiling water should be poured over the area, followed by heavy watering and letting it sit for some time. If no rabbits survive, the enclosure should remain empty for at least 6 months to avoid any risk to newly introduced rabbits. Additionally, meadow areas cannot be disinfected and should not be used for rabbits for 3.5 months. The area should be heavily watered and regularly mowed. New rabbits should be vaccinated twice against RHDv and RHDv2 before being introduced to the enclosure.

As an alternative to disinfection, a new enclosure can be set up for the surviving rabbits at a different location in the garden.

Prevention: How to Prevent Your Rabbits from Contracting RHD

The most important preventive measure against RHD is vaccination against both RHD1 and RHD2, as these vaccines offer strong protection and are the most well-tolerated for rabbits. Unfortunately, the commonly recommended two-dose vaccination series with RHD1-only vaccines does not provide sufficient protection against RHD2. Therefore, Eravac, Nobivac Myxo-RHD Plus, or Filavac should be used for optimal protection against both strains of the virus.

Additional Protective Measures Against RHD:

• Maintain a Stable Rabbit Population: Avoid frequent changes in the rabbit group (such as through vacation care or introducing new rabbits) to minimize potential exposure to the virus.

• Avoid Contact with Wild Rabbits and Hares: Prevent direct or indirect contact with wild rabbits or hares. For example, ensure that the enclosure has two separate, secure fences with a gap between them to prevent any possible contact.

• Quarantine for New Rabbits: New rabbits should undergo a two- to three-week quarantine period before being introduced to the main group to ensure they do not carry the virus.

• Protection from Insects: Fly protection is crucial, as insects can transmit various rabbit diseases, including RHD(2), Myxomatosis, Tularemia, and flystrike. Using fly screens on windows (for indoor rabbits) or over the cages (for outdoor rabbits) is beneficial.
  You may also consider using spot-on treatments such as Advantix (with Permethrin & Imidacloprid) to protect against insects. Consult a knowledgeable rabbit veterinarian for advice on the correct dosage. Spot-on treatments can be applied every two weeks, with appropriate dosages based on the rabbit’s weight.
  Be aware that some rabbits may have mild skin reactions (e.g., hair loss or irritation).

• Avoid Feeding Wild-Harvested Greens: Avoid feeding wild greens from areas where infected wild rabbits or hares live. Even hay (including packaged hay) and supermarket vegetables could have been exposed to the virus, especially if they come from regions where RHD is common.
  The virus is not killed by heating, so even dried foods or vegetables may carry the risk of transmission. It’s safest to feed your rabbits greens and branches from unaffected areas.

• Be Cautious When RHD is Present in the Area: If RHD outbreaks are reported nearby, exercise heightened caution. Avoid borrowing items from other rabbit owners, limit interactions with other rabbits, and take extra precautions during veterinary visits.

• Pets in the Household: If you have dogs or cats at home, ensure that they are not fed uncooked rabbit or hare meat, as this could facilitate virus transmission.

• Hygiene Measures: Regularly wash your hands, especially after leaving your home or handling other animals, before interacting with your rabbits.
  If you come into contact with other rabbits, change your clothes and wash your hands thoroughly before handling your own rabbits.

• Clean Shoes and Accessories: When you come home from places where you might have been in contact with other rabbits or animals, remove shoes and change clothes before entering areas where your rabbits live.
  Store shoes and clothes outside or in an isolated area to reduce the risk of contamination.

• Source Safe Equipment: Ensure that any used equipment, accessories, or cages come from reliable sources and are properly disinfected with effective virucidal products to avoid contamination.

For exhibition animals, vaccination is mandatory.

Vaccination is typically done according to the manufacturer’s instructions, usually once or twice a year (preferably in the spring), as the vaccine provides protection for nine to twelve months, depending on the vaccine used. The International Animal Health Organization (OIE) considers the minimum protection duration for RHD1 vaccinations to be 16 months.

For baby rabbits, a basic immunization (two vaccinations with a four-week interval) is recommended, especially in epidemic areas, to ensure that rabbits not covered by the first vaccination are adequately protected.

The vaccination is most effective when the rabbits are in perfect health and free of coccidia, worms, or other parasites. A thorough general health check and a parasitic stool sample should be conducted before every vaccination to ensure the animal is free of any infections that could affect the immune response.

Vaccines for RHD1

Approved vaccines in Germany for RHD1 (inactivated vaccines):

• CASTOREX
• CUNIVAK RHD
• Lapimed RHD
• RIKA – VACC RHD

Approved combination vaccines (combined with Myxomatosis):

• NOBIVAC Myxo-RHD
• CUNIVAK COMBO
• Dercunimix
• RIKA – VACC Duo
  (approved by the Paul Ehrlich Institute, 2005)

Approved triple vaccine (combined with Myxomatosis and RHD2):

• Nobivac Myxo-RHD Plus

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Vaccines for RHD2

• Eravac (EU-wide, only for RHD2)
• Nobivac Myxo-RHD Plus (EU-wide, includes Myxomatosis and RHD1)
• Filavac (available nationwide in Germany, includes RHD1)

Testimonial: My RHD Outbreak (Essen/NRW Area)

„In March 2024, I enthusiastically began keeping rabbits. In no time, they had captured my heart. I knew nothing about the dangers of RHD (Rabbit Hemorrhagic Disease), a highly contagious and often fatal disease that affects rabbits. Most importantly, I didn’t realize how crucial it is to vaccinate rabbits against it. All my rabbits had visited a vet; I proudly showed off my setup, and everyone admired them. The male rabbit was neutered and considered wonderful. But we never talked about vaccinations.

Then came the shock: On a Monday morning at 8:00 AM, I opened the doors of the winter garden to let my rabbits out into their outdoor enclosure. They were all fine, nothing seemed off. When I returned at 10:00 AM, my little „Fee“ was dead in the enclosure, not on her side, but on all four paws, with a bit of blood around her nose. I was devastated and cried bitterly. I wondered if she had injured herself or what had happened. I had no idea there was something called “Rabbit Plague.” I spent most of the day in my winter garden with the rest of my rabbits, and they seemed fine. Nothing out of the ordinary.

The next day, three more rabbits died. There were barely any symptoms beforehand. I wouldn’t wish this awful experience on anyone.

Within just a few days, my rabbits died from the RHD virus. The pain and guilt I felt from their terrible deaths are hard to put into words. It all happened so quickly. I felt utterly helpless. I’m sharing this to reach other rabbit owners who may not know enough about RHD and other risks. Get informed. Ask your vet about the necessary vaccinations. Educate yourself actively.

Don’t wait until it’s too late. I could have spared myself so much pain—and, most importantly, my animals. I miss them endlessly.

My last surviving rabbit is now doubly vaccinated. And from now on, there will be no more important appointments for my rabbits than their vaccinations. I talked about this on Instagram, and I’ve seen others become aware and go for their vaccinations because of it.

Sending love,
Jen“

Sources, including:

Diverse Herstelleranfragen, Packungsbeilagen und Herstellerangaben
Abrantes, J., Van Der Loo, W., Le Pendu, J., & Esteves, P. J. (2012): Rabbit haemorrhagic disease (RHD) and rabbit haemorrhagic disease virus (RHDV): a review. Vet Res, 43(1), 12.
Friedrich Löffler Institut (2017): FAQ zur Hämorrhagischen Krankheit der Kaninchen (RHDV,RHDV-2)
Liebscher, J., & Hein, J. (2021): Alles neu?!–Typische und untypische Infektionserreger beim Kaninchen. kleintier konkret, 24(S 01), 10-17.
Phouratsamay, A., Barbarino, A., Marolles, G., Juster, G., Martinot, E., Raymond, P., … & Coutant, T. (2024): SUCCESSFUL MEDICAL MANAGEMENT OF A RABBIT HAEMORRHAGIC DISEASE VIRUS 2 INFECTION IN A PET RABBIT (ORYCTOLAGUS CUNICULUS). Journal of Exotic Pet Medicine.
StIKo Vet (2016): Stellungnahme der StIKo Vet zur Immunisierung von Kaninchen gegen RHDV-2
StIKo Vet (2016): Aktualisierte Stellungnahme der StIKo Vet zur Immunisierung von Kaninchen gegen RHDV-2
StIKo Vet (2017): Hinweis auf neue RHDV-2-Impfstoffe