Rabbit Hemorrhagic Disease (RHDV) is a fatal disease that affects rabbits and is considered a foreign animal disease in the United States. This disease is caused by several virus strains but the RHDV-2 strain, is highly contagious and unlike other rabbit hemorrhagic disease viruses, it affects both domestic and wild rabbits.

Since March 2020, RHDV-2 has been confirmed in four wild species: Black-tailed Jackrabbits, Desert cottontail, Antelope jackrabbit, and the Mountain cottontail. It has also been confirmed in domestic rabbits and feral domestic rabbits.

RHDV-2 can enter the body through the oral, nasal, or conjunctival routes, though oral transmission is thought to predominate. Most of all secretions and excretions from infected rabbits, including urine, feces, and respiratory secretions, are thought to contain the virus. There are no published reports of transplacental transmission of RHDV-2. This virus readily spreads on various fomites (objects or materials) including contaminated food, bedding, water, clothing, cages, and equipment. Transmission via fomites and surroundings are of special concern due to the stability of the virus on organic materials and the low dose needed to cause infection.

Insects might transmit this virus long distances. Birds and mammals that prey on lagomorphs may be mechanical carriers and excrete infectious viruses in feces after eating infected rabbits.
One of the most important things to remember is that this virus is highly contagious.

The incubation period for RHDV-2 is 3-5 days in most cases. RHDV-2 infections are usually subclinical (no detectable clinical signs) in rabbits less than 4-8 weeks of age.

Peracute and acute disease are the most common syndromes in older rabbits. Peracutely affected animals develop a fever and die suddenly within 12 to 36 hours of its onset. The only clinical signs may be terminal squeals, quickly followed by collapse and death. Animals with acute RHDV-2 survive somewhat longer, with nonspecific signs such as depression, anorexia, congestion of the conjunctiva and/or prostration (lying stretched out on the ground), and, in some cases, respiratory signs (e.g., dyspnea, cyanosis, and a terminal bloodstained, frothy nasal discharge), lacrimation, ocular hemorrhages or epistaxis (bleeding from the nose). Some rabbits also have neurological signs such as incoordination, opisthotonos, and paddling. Affected animals sometimes turn and flip quickly in their cages, resembling convulsions or mania.

Rabbits that survive longer (subacute cases) can develop severe jaundice, with weight loss and lethargy, and often die from liver dysfunction, typically within a few weeks. Diarrhea, constipation, and abdominal dilatation are sometimes seen just before death. Milder signs or subclinical infections have also been reported occasionally in adult rabbits. This form of the disease may cause affected rabbits to survive minor clinical symptoms and develop antibodies.

The virus can remain stable for 3 months when dried, but, exposed RHDV-2 typically does not persist in excretions on surroundings longer than a few weeks and grows less viable over time.
Chilled, frozen, and decomposing rabbit meat can harbor RHDV-2 for several months and presents a significant risk of introducing the disease during trade, as blood viral titers are particularly high. This may provide a reservoir of disease after outbreaks in the wild, as a viable virus has been found in decaying tissue after 90 days outdoors. The fur of an infected rabbit can be a source of RHDV-2 transmission. Pelt and hair trading among countries with an active fur industry may lead to further spread of the virus.

The is no specific treatment for this disease at this time. Treatment is currently limited to supportive care.

As of May 2020, RHDV-2 had been diagnosed in rabbits in the states of California, Nevada, Arizona, New Mexico, Colorado, and Texas. On December 30, 2020, there was an outbreak in Lake County, Florida in which 18 rabbits passed away from this virus. We have requested the Florida Department of Agriculture and Consumer Services (FDACS) to grant us permission to import vaccines from Europe to protect our rabbits from this disease, but so far FDACS has not approved any importation of this vaccine to Florida.

Please visit our Facebook page (Exotic Animal Hospital of Orlando) to find a handout with extensive recommendations on measures that can be taken to prevent your pet rabbit from getting this disease.