What is RVHD?
Viral haemorrhagic disease (also known as rabbit calicivirus disease or rabbit haemorrhagic disease) is a highly infectious and rapidly fatal form of viral hepatitis that affects European rabbits. The disease is caused by the rabbit hemorrhagic disease virus (RHDV) and has historically been used in some countries to control feral rabbit populations.
How is RVHD spread?
The virus is very hardy and can survive in the environment for months. It can survive freezing temperatures and those up to 50 degrees C for an hour. RVHD is highly contagious and can be spread in a number of ways, including;
- Contact with infected rabbits and contaminated surfaces
- Contact with the urine or faeces of an infected rabbit
- Insects (including flies, fleas and mosquitos) which can transport the virus
- Scavenger birds that have eaten the carcass of an infected rabbit can pass the virus on in their droppings
- Humans who have been in contact with infected rabbits transporting the virus on their clothes
Ingestion of contaminated food or water.
What are the clinical signs of RVHD?
RVHD attacks the internal organs of the affected rabbit (especially the liver) and causes huge internal bleeding. There are two types of RVHD (RHD1 and RHD2.
RHD1 was the only known variation of the disease until 2013. It is extremely aggressive with a 90% mortality rate for unvaccinated rabbits, however young rabbits under four weeks old appear to have a natural immunity and will be protected for their first few weeks of life.
RVHD causes blood clots to form within the blood vessels of the heart, lungs, liver and kidneys. These clots cause rupture of the blood vessels and massive internal bleeding.
Once infected, rabbits sadly often die within two to four days and there may be no symptoms leading up to sudden death. Other rabbits may exhibit signs of lethargy, fever and an increased respiratory rate, followed by blood around the nose, mouth and anus.
Unfortunately, the virus can mutate and there is now a new strain of RVHD in the UK. RHD2 was first identified in the UK in 2013 studies suggest it has been here for longer.
This new strain of the disease can affect young rabbits under 4 four weeks of age and the incubation time is longer at (three to nine days). Fortunately, the mortality rate is lower at 5-70%, however, the longer incubation time and lower mortality means that RHD2 virus was more likely to spread that the original strain.
How is RVHD diagnosed?
Viral haemorrhagic disease is usually diagnosed after the animal has died due to the speed of the fatal effects it produces. Samples are sent to veterinary laboratories where the virus can be isolated.
How is RVHD treated?
Unfortunately, there is no cure for viral haemorrhagic disease. In very mild cases then supportive therapy may be attempted to reduce the symptoms and antibiotics are occasionally given to prevent secondary bacterial infections.
Sadly, most unvaccinated rabbits will die with or without treatment and most infected and unvaccinated animals are euthanized to prevent further suffering.
How can you protect against VHD?
RVHD vaccines are very effective. Your rabbits can be protected against both strains of RVHD by vaccination any time from five weeks of age, with a booster every 12 months.
It’s very important to clean and disinfect anything that may be carrying the viruses, including water bottles, bowls, bedding and housing. Anything that has been touched by an unknown rabbit should be thoroughly cleaned and treated with virus killing agents.
Rabbit Health Information
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To assist owners in understanding more about a health conditions that are specific to rabbits we have put together a range of information sheets to talk you through some of the more common health concerns seen and treated by our General Practice Vets.