At Blue Mountain Hay, we are unwavering in our commitment to the well-being and health of the animals we serve. We understand the crucial role that high-quality hay plays in the nutrition and overall health of animals. That’s why we take pride in providing premium hay products that are carefully selected and harvested to meet the specific dietary needs of each animal.
Beyond offering quality hay to your animals, we partner with a seasoned veterinarian in order to extend authoritative, excellent educational resources on animal care. We truly hope that you do not find your cherished pet suffering from any disease, especially RHDV2 in rabbits. Nonetheless, it’s important to educate yourself in order to feel confident in providing quality care to your rabbit.
Yes, RHDV1 does exist! First identified in 1984, Rabbit Hemorrhagic Virus, now commonly known as RHD, RHDVa, or RHDV1, affected only European rabbits. A particularly deadly virus, with a mortality of up to 90%, this calicivirus affected primarily adult rabbits and was contracted primarily via the oral route.
Transmission occurred through infected rabbits, contaminated items, and people and other animals which had been in contact with a deceased rabbit. Very young rabbits were largely protected by maternal antibodies, while adult rabbits were the primary victims. There were substantial negative economic and environmental effects as this virus spread across Europe in the mid to late 1990’s.
What is Rabbit Hemorrhagic Disease Virus 2 (RHDV2)?
In 2010, RHDV2 was discovered in France and remains distinct from RHDV1. Rabbits and hares other than European rabbits were found to be susceptible. While mortality ranges from 50 – 80%, this calicivirus causes disease and death of young rabbits and hares, which greatly aids its spread.
Since 2010, RHVD2 has spread across Europe, and has been found in North Africa, West Africa, North America, Central America, and has replaced RHDV1 in Australia. Unfortunately, there are dramatic effects of this new variation on domestic rabbits, wild rabbits, hares, and wildlife. For example, it is estimated that there has been a reduction of 60 -70% in the population of wild European rabbits. With this decline, animals which depend upon the European rabbit for survival have also experienced reduced survival, among them endangered species.
In 2018, RHDV2 was discovered in Ohio, United States. In 2020, a distinct RHDV2 was found in domestic and wild rabbits in New Mexico; the Southwest United States continues to maintain a distinct strain of this virus. A distinct strain has also been found in northern Washington State, on Whidbey Island. As per the Washington State Veterinarian, whole genome sequencing indicates that the Whidbey Island strain is different from the Vancouver strain of 2019.
What is the mortality rate for RHDV2?
Rabbit mortality is generally reported as 50-80%. To further clarify, a 2022 outbreak in California was reported to have a 60% mortality, with a range of 20-100%.
What makes RHDV2 so problematic?
Due to the ease of transmission and environmental persistence, RHDV2 is easily ingested or inhaled by rabbits and hares. Consider these facts:
Rabbits or hares which survive infection can shed this virus into the environment for 42 days
Viral persistence may last in the environment for 3-4 months
This virus survives 122 degrees fahrenheit for an hour
Freeze/thaw cycles do not destroy RHDV2
How is RHDV2 passed on to other rabbits or animals?
There are several ways that RHDV2 can be passed on to other animals:
The feces of carnivores which consume affected rabbits (the carnivores so far are themselves unaffected).
Birds or domestic animals may also become contaminated, spreading the virus
Direct contact with infected rabbits or hares, whether alive or deceased
Indirect contact with exposed materials: carriers, towels, shoes, equipment, vehicles
Insects, especially flies, can transmit this disease readily
People unknowingly can transmit this disease on their hands and clothing
Eating contaminated food and/or water
Incubation: from exposure to demonstration of clinical signs ranges from 1 – 9 days. During this time period a rabbit and its people may be spreading the virus to others. Some rabbits never show any clinical signs at all, and succumb suddenly.
How Does RHDV2 Affect Rabbits?
This virus targets the rabbit’s liver. As a result, the affected rabbit can no longer produce adequate clotting factors, and so hemorrhage ensues. While the classic picture is of a rabbit who has clear signs of hemorrhage (bleeding from the nose, mouth, or other orifices), others may present first with some inappetence, lethargy, signs of GI stasis, jaundice, difficulty breathing, and/or convulsions.
If you find a deceased rabbit or hare which you suspect has RHDV2, do not move the rabbit from the site. Notify your State Veterinarian (State Department of Agriculture).
What Can You Do to Help Stop RHDV2 in Rabbits?
We know you want to help your rabbits and those around your area to be safe and unharmed by RHDV2. As a result, we have provided you with links to resources that will provide additional, valuable information.
The Oregon Department of Agriculture created a wonderful review of biosecurity. While this document was created in 2021 – meaning that the vaccination information is outdated – it still provides excellent information.
Give your rabbit the RHDV2 vaccine. Medgene Labs has developed a vaccination, which is available to veterinarians. Each state veterinarian must authorize use of this vaccination in their states. Medgene’s website includes a product summary, white paper, FAQs, and a document detailing a rabbit challenge study.
How Can We, As A Community, Help to Lessen the Transmission of RHDV2 in Rabbits?
As a community member you can do your part by incorporating these points into your daily life:
All rabbit enthusiasts and outdoor enthusiasts can remain vigilant in biosecurity, both in the home, and in travel.
Be aware of any reported outbreaks in your home area, or in your destination.
Leave rabbits at home whenever possible, educating caretakers as to best practices.
Be mindful when out-of-doors, avoiding areas which have had recently reported outbreaks.
Consider sponsoring vaccinations for rabbits in need, such as those in shelters and in humane societies.
Have your rabbits vaccinated, and continue to maintain those vaccinations. Vaccinated pet rabbits help to prevent the spread of disease to others, and in large part help to protect their wild cousins, who are very much at risk. Lessons from Europe tell us that outbreaks in wild populations affect so many.
Is the RHDV2 vaccine for rabbits yearly?
Your rabbit will initially receive two portions of the RHDV2 vaccine three weeks (21 days) apart from each other. But after those doses, a yearly vaccine booster is required in order to ensure that your rabbit maintains immunity.
How do indoor rabbits get RHDV2?
Indoor rabbits may develop RHDV2 in the following ways:
Direct contact with infected rabbits or hares, whether alive or deceased
RHDV2 is spread by insects; flies can transmit this disease readily
People unknowingly can transmit this disease on their hands and clothing
In some outbreaks, the mode of transmission was not identified.
What are the side effects of the RHDV2 vaccine in rabbits?
According to Medgene Labs, Rabbits may develop a “small swelling at the site of the injection, develop a slight temporary fever, or be lethargic for a day or two” after receiving the RHDV2 vaccine. For more up-to-date information, check out their website.
What is Blue Mountain Hay doing?
Blue Mountain Hay is located in the state of Oregon. With our veterinarian, we follow our states’ reporting agencies closely, including the Facebook group Rabbit Hemorrhagic Disease Network and the interactive maps depicting reported cases of RHDV2.
We follow best practices for hay production and storage. Our hay is stored for 4 months prior to shipment in order to avoiding transmitting RHDV2 to your beloved rabbits. If you would like more information on our hay products for rabbits, explore our hay school’s information on oat hay, alfalfa hay, and timothy hay for rabbits. Check out our website for some of our other products, like our organic garden straw mulch, or organic litter pellets.
As a veterinarian of over thirty years, Dr. Vickstrom brings her authoritative knowledge of exotic animal health to each blog post Review. To read her full bio, click here.
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