Leaping Across the U.S.: Rabbit Hemorrhagic Disease

Imagine walking into a rabbitry one day and noticing multiple rabbits dead with nothing other than a little bit of blood on their nose. A highly contagious foreign animal disease by the name of rabbit hemorrhagic disease (RHD) is on the rise nationally, and is causing many rabbit farmers and owners to fear for their stock and pets. While it poses no threat to humans, the disease can be deadly to rabbits.

What is RHD?

RHD is preceded by just a few symptoms like reluctance to eat, fever, difficulty breathing or seizures. It is can be a silent killer that leaves rabbits suddenly dead with only blood-stained noses (U.S. Department of Agriculture, 2020). The RHD virus is non-enveloped, difficult to detect, and can survive on carcasses in mild or extreme climates. These characteristics explain why RHD can be transmitted directly (animal-to-animal) as well as indirectly. For example, farmers walking around their property can indirectly track back the disease to their own rabbits if they come into contact with grass contaminated by feces or urine from a wild rabbit with RHD. To learn more about methods of animal disease transmission, visit the Healthy Farm Healthy Agriculture website’s routes of infection learning module.

While an onslaught of RHD is sudden and often devastating, some signs to look out for in an infected animal include:

• Poor appetite
• Depression, lethargy or listlessness
• Fever
• Bloody nasal discharge

Weight loss, bloating, diarrhea, respiratory disease and jaundice are indicative of organ failure, which comes in the later stages of the disease (Washington Department of Agriculture, 2020). Contact a veterinarian immediately if there are any sudden deaths or any of the signs listed above.

Where is RHD Found?

Outbreaks of rabbit hemorrhagic diseases (RHDs) are not uncommon. One of the first-ever diagnoses of RHD occurred in China in 1984 (Washington Department of Agriculture, 2020). In 2019, there was an RHD outbreak in the State of Washington and in the adjacent Canadian islands. This year, RHD is spreading through several states, but the virus strain in the southwestern United States is different from the one found in Washington. Since March 2020, cases have been confirmed in:

• Arizona
• California
• Colorado
• New Mexico
• Nevada
• Texas
• Utah
• Northern Mexico.

The current strain of RHD (RHDV2) is the first to be deadly to both domestic and wild rabbits (House Rabbit Society, 2020). A map with the locations of RHD cases can be viewed on the USDA APHIS website.

Biosecurity to Protect Rabbits and Prevent RHD Spread

Biosecurity practices can prevent RHD in rabbits, whether they are raised for pets or sale. The following steps will help to keep animals safe and healthy:

• Wash hands before and after coming into direct contact with rabbits (wild or domestic) or entering a rabbitry.
• Frequently sanitize and disinfect equipment used for the care or holding of rabbits. Phenolics or 10 percent bleach are recommended. For help on how to read a disinfectant product label correctly, read this guide from the Center for Food Security and Public Health.
• Do not allow contact between domestic and wild rabbits.
• Have all workers and visitors wear protective clothing such as gloves, coveralls, shoe and hair coverings.
• Isolate any new animals or animals that have been off of the premises for 30 days. Use separate equipment for these animals during the isolation period.
• If possible, avoid taking rabbits to shows because it might put them at risk for infection. As of June 26, 2020, the state veterinarian of Oklahoma has banned rabbit exhibitions for the time being.
• Do not feed grass that could be contaminated or use branches for bedding if they were found outside.
• Remove dead rabbits in a rabbitry immediately and submit them to a veterinarian for examination.
• Keep rabbits indoors as much as possible.

In addition to following those steps, it is crucial to report any cases of dead wild rabbits to local and state veterinarians: avoid all direct contact with dead wild rabbits if possible. Wildlife professionals investigating deaths of wild rabbits are urged to practice strict biosecurity to avoid spreading the virus.

While there is no commercially available vaccine for RHD in the United States, there are three vaccines available in Europe. Two of these vaccines (Filavac and Eravac) may be used in the United States in the case of an emergency if a permit is acquired. (United States Department of Agriculture, 2020). Additional details about vaccines can be found in this RHDV2 FAQ sheet by the USDA. If you would like more information or to inquire about vaccinating rabbits against RHD in the United States, contact your local or state veterinarian.

It is disturbing to think that livestock or pets can be healthy one day but gone the next. However, even highly contagious and high consequence diseases can be managed with the right biosecurity practices. To learn about assessing the risk of diseases and how to lessen these risks, take the biosecurity risk assessment on the Healthy Farms Healthy Agriculture website.

References

House Rabbit Society (2020, June 18). Rabbit Hemorrhagic Disease Virus (RHDV).
Retrieved from https://rabbit.org/rhdv/

U.S. Department of Agriculture, Animal and Plant Health Inspection Services (2020). Rabbit Hemorrhagic Disease [Fact sheet].
Retrieved from https://www.aphis.usda.gov/publications/animal_health/fs-rhdv2.pdf

Washington State Department of Agriculture (2020). Rabbit Hemorrhagic Disease [Fact sheet].
Retrieved from https://cms.agr.wa.gov/getmedia/07915d2d-bfd5-4cbb-b443-ab3b42b72722/RHDFactsheet

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About the Author
Katie Loberti
Katie Loberti was an undergraduate student at the University of Vermont pursuing a bachelor's degree in animal science. In the past, she worked as a park naturalist at Burlingame State Park in Rhode Island, which allowed her to grow and share her knowledge and passion for wildlife in New England with others. She also volunteered at Biomes Marine Biology Center in Rhode Island which helped her discover her love for aquatic life. At the University of Vermont, Katie was an active member of the women's rugby club. In the future, Katie hopes to pursue veterinary medicine or do work with animal conservation and education.

About the Editor
Joanna Cummings
Cummings received a bachelor of science degree in horticulture from The Pennsylvania State University, with a specialization in vegetable crop and greenhouse production. At PSU, she was a research technician on no-tillage vegetable crop experiments, and a greenhouse assistant in the All-American Selections Research Gardens. Her career in the agriculture industry includes field research, work with dairy and vegetable farms, and as a greenhouse manager, estate gardener, landscaper and market garden entrepreneur. She transitioned to the science communication field after receiving a master of science degree in environmental communications from Antioch University New England. At Antioch, she was a field botany laboratory teaching assistant and manager of the herbarium.
She works with Associate Research Professor Julie M. Smith, DVM, PhD, as a communications professional in the University of Vermont Animal and Veterinary Sciences Department. She is the webmaster for the Healthy Farms Healthy Agriculture website.

About the Editor
Dr. Julie Smith
Dr. Julie Smith is a research associate professor at the University of Vermont. Julie received her B.S. in Biological Sciences, D.V.M., and Ph.D. in Animal Nutrition at Cornell University. Since 2002, she has applied her veterinary background to programs in the areas of herd health, calf and heifer management, and agricultural emergency management. She has taught Animal Welfare, Calf Biology and Management, and ABCs of Biosecurity to undergraduates, mostly in the Department of Animal and Veterinary Sciences. 
As a veterinarian and spouse of a dairy farmer, Julie is well aware of the animal health and well-being concerns of dairy animals. Julie has conducted trainings for Extension educators, livestock producers, and community members on the risks posed by a range of animal diseases, whether they already exist in the United States, exist outside of the United States, or pose a risk to both animal and human health. In all cases, she emphasizes the importance of awareness and prevention. In addition, she has led a number of projects on biosecurity and emergency disease preparedness.