Rabbit Hemorrhagic Disease Virus (RHDV) is a highly contagious and fatal disease that affects both wild and domestic rabbits. Until 2020, it had not been known to affect any North American native rabbits, however, cases of the disease have been reported in cottontail rabbits and hares as well as in domestic rabbits in states including Arizona, California, Colorado, Nevada, New Mexico, New York, Texas, and Washington.
There are two strains of rabbit hemorrhagic disease virus or viral hemorrhagic disease (VHD) and both of them are extremely contagious, have few to no symptoms and are fatal in most cases. The RHD virus causes lesions throughout internal organs and tissues, particularly the liver, lungs and heart, resulting in bleeding. The new strain RHDV2 was first recognized several years ago but over the past year it has become increasingly prevalent. RHD does not pose a threat to humans, other animals or the food supply.
The time from infection to first signs of disease may be up to nine days. Symptoms may include: weariness, loss of appetite, incoordination, seizures, congested membranes around the eyes, signs of nervousness, difficulty breathing and/or bleeding from nose, mouth, or rectum. Treatment is generally limited to supportive care, with infected rabbits isolated from all other animals. Affected rabbits may develop a fever and die within 36 hours. Mortality rates range between 40% and 70% for RHDV2.
A vaccine for RHDV2 is not currently available in the United States. Absent a vaccine, the best way to protect rabbits is with to utilize increased biosecurity measures such as not sharing equipment with other rabbit owners; and disinfecting all equipment, such as waterers and feeders, that come into contact with rabbits.
According to the United States Department of Agriculture, a very low dose, possibly as little as a few viral particles, is enough to cause infection. The virus is highly stable, especially in organic materials, and can remain viable for months in varied temperatures and over distances, enabling it to be spread by biting insects (flies, fleas, mosquitoes) and birds.
Domestic rabbits should not be housed outdoors in areas where rabbit hemorrhagic disease has been detected in wild rabbits. Rabbit owners should exercise extreme caution and biosecurity to avoid accidental exposure of domestic rabbits through contaminated feed, water, bedding, equipment, or clothing that may have come in contact from infected rabbits. People can spread the virus indirectly by carrying it on their clothing and shoes.
More information can be found in the following resources:
- USDA Fact Sheet on Rabbit Hemorrhagic Disease
- Quick Facts About Rabbit Hemorrhagic Disease
- USDA Guidance for Cleaning and Disinfection of RHDV Contaminated Premises
- Keep Your Rabbits Safe From Rabbit Hemorrhagic Disease – Biosecurity Recommendations
By Jeannette Rea Keywood, State 4-H Agent, Department of 4-H Youth Development, Rutgers Cooperative Extension