Rabbit Hemorrhagic Disease
Rabbit hemorrhagic disease virus (RHDV), also known as viral hemorrhagic disease (VHD) is a contagious viral disease caused by a calicivirus. This virus mainly affects European pet rabbits. However, a newer strain identified in the US in 2018 is also capable of infecting our wild rabbits, including Eastern cottontails, wild hares, and jack rabbits. The original RHDV resulted in death in 90-100% of infected adults. Luckily, the newer strains are less severe with a 20-30% fatality rate. There are more than 400 strains of RHDV identified, and the virus has spread across the globe with infections seen on all continents other than Antarctica. Continue reading to learn how RHDV is spread and how to protect your rabbit.
How is rabbit hemorrhagic disease spread?
The virus is spread by direct contact with infected rabbits and through feces that are ingested. It can also spread on bedding, bowls, and bottles. The virus can survive outdoors for up to 7 weeks.
RHDV can also live in the GI tract of foxes, dogs, bird scavengers, and polecats that have eaten an infected rabbit. The predators do not get sick from the virus but can spread it over large distances, infecting other rabbits.
Biting insects such as flies, mosquitoes, and blowflies can also spread the virus.
Finally, the virus can survive on rabbits that are dead, including their meat/muscles and skin/pelts. It is through this route that the virus was able to spread over many continents in trade.
Rabbits that are under 8 weeks of age and are exposed may never get sick from the virus and develop lifelong immunity. This may not be the case for all the mutations of the virus.
What symptoms might be seen if my rabbit is infected with RHDV?
Once exposed, rabbits typically become ill within 12 to 72 hours. Symptoms can persist for 7 to 14 days. RHDV can be fatal to rabbits. The most common symptoms of rabbit hemorrhagic disease include:
- Acute death with no prior symptoms
- Fever, often over 104F
- Discharge from the eyes and/or nose
- Neurologic symptoms such as ataxia, tremors, seizures, depression, inability to use rear limbs normally, flexing the neck and head upward
- Blue color to the gums and tongue
- Laying on the side unable to sit up
- Abnormal or difficulty breathing
- Blood from the nose, mouth, rectum
- Yellow discoloration to the skin or eyes
- Diarrhea or constipation
What tests might my vet recommend to diagnose rabbit hemorrhagic disease?
Routine blood work is often a good starting point. Rabbits with RHDV often have abnormal white blood cell levels and may have low platelets. The virus attacks the liver, so the liver enzymes are often increased within 6 hours of infection. Kidney enzymes may also rise. The blood sugar level may drop severely and this indicates severe liver failure and typically death within 24 hours.
Since coagulation/clotting issues are common with RHDV, your vet may recommend coagulation testing.
ELISA and PCR tests are available, but not widely in the US yet. Your vet may need to make a special request to get these tests performed at the National Veterinary Diagnostic Lab. These tests can have false results and are often more reliable if run on tissue samples from the liver. Unfortunately, this means the best samples are obtained after the rabbit has passed away.
What treatments are available for rabbit hemorrhagic disease?
There is no specific treatment for this viral infection in rabbits. Treatment is aimed at supportive care. Many rabbits are in shock or dehydrated, so intravenous fluids are often administered. If your rabbit has abnormal electrolyte levels, medications can be added to the fluids to help correct this.
Some rabbits have lost enough blood that they need a blood transfusion. Since RHDV can cause clotting and coagulation issues, medications may be started to help reduce bleeding. Vitamin K, Desmopressin, and Low Molecular Weight Heparin are all possible therapies.
Since RHDV can cause liver failure, liver-supportive medications are often used. Silymarin, SAMe, and N-acetylcysteine may be recommended.
GI protective medications are another common part of supportive care. Rabbits that are not eating and have liver disease are more prone to develop GI ulcers.
How can I protect my rabbit from getting rabbit hemorrhagic disease?
- While there are vaccines for RHDV in other countries, there is not a vaccine available in the US at this time.
- Keeping your rabbit indoors and away from wild rabbits and insects can help reduce infection risk.
- If your rabbit is housed outside, keeping them in an elevated hutch with good insect control and netting can keep them safer.
- If you had a rabbit with RHDV, discard all bedding, bowls, and housing that cannot be thoroughly cleaned. Bleach can be used to disinfect any non-porous surfaces.
Keeping Your Rabbit’s Digestive System Healthy
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