Rabbit Hemorrhagic Disease Virus (RHDV)

May 26, 2020

Rabbit Hemorrhagic Disease Virus (RHDV)
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What is Rabbit Hemorrhagic Disease Virus?

Current Outbreaks 2018-2020

How RHDV Is Spread

How to Protect Your Rabbits

Vaccination

Availability of Vaccines

Vaccine Info for Veterinarians

About the Vaccines

Recommended Protocols for Animal Shelters and Rescue Facilities

What You Can Do

What is the Government Doing?

Past US Outbreaks 2000-2018

HRS Policies and Guidelines Regarding RHDV

What is Rabbit Hemorrhagic Disease Virus?

Rabbit Hemorrhagic Disease Virus (RHDV) is a highly contagious disease caused by a calicivirus that affects rabbits. This includes wild and domesticated European rabbits (Oryctolagus cuniculus), from which our own domesticated rabbits are descended. Until 2020, it had not been known to affect any North American native rabbits or hares, such as cottontails, snowshoe hares and jackrabbits, however, now it has been confirmed in the 2020 Southwest outbreak in causing death in these wildlife species as well.

RHDV was first seen in China in 1984, and since there have been confirmed cases in 40 countries, including in Europe, the Mediterranean, Africa, Asia, Israel, the UK, Mexico, the US, Canada, Australia and New Zealand. RHDV2, a second strain, emerged in France in 2010, and quickly spread in Europe and the Mediterranean, and has replaced the original strain in many countries. In 2015, RHDV2 was first detected in Australia, and it spread coast-to-coast in the rabbit population in 18 months and became the dominant strain replacing RHDV1.

Symptoms may include:

  • Loss of appetite
  • Lethargy
  • High fever
  • Seizures
  • Jaundice
  • Bleeding from nose, mouth, or rectum
  • Difficulty breathing
  • Sudden death

RHDV is often a very swift and sudden killer, giving little warning. Rabbits may die without showing any symptoms at all. Any sudden rabbit death is suspicious and should be reported to your veterinarian as a possible case of RHDV.

  • The incubation period for RHDV1 is 2-10 days, and RHDV2 is 3-9 days.
  • The death rate of rabbits exposed to this virus is very high, between 40-100% for RHDV1 and 5-70%+ for RHDV2. Rabbits who survive are carriers and shed the virus for at least 42 days, perhaps longer.
  • Some rabbits may have little to no symptoms of RHDV2 (subclinical), but may shed virus for up to 2 months.
  • RHDV causes necrotizing hepatitis, and may cause necrosis of the spleen. There may be internal or externally visible bleeding. Death occurs from liver failure or hemorrhage due to an impairment in the blood’s ability to clot.
  • Rabbit calicivirus is a very hardy virus, remaining viable in the environment for 105 days at 68F on fabric – it remains stable for 105 days at room temperature – and for 225 days at 39F. It is not killed by freezing. It survives heat of 122F for one hour.
  • There is no known cure for RHDV.
  • RHDV2 treatment is supportive care in isolation. There are currently no known effective anti-viral drugs or other treatments available.

Current Outbreaks 2018-2020

2020 Southwest
(Arizona, California, Colorado, Nevada, New Mexico, Texas, Mexico)

The RHDV2 virus spreading in the Southwest in 2020 has been found to be a single genetic isolate, distinct from previous outbreaks in the Pacific Northwest (WA and Canada), New York, and Ohio.

Here’s an interactive map of the Southwest Outbreak from the USDA.

May 2020 California – Wild rabbits died of RHDV2 in: Palm Springs (Riverside County).
April 2020 Nevada – Domestic rabbits died of RHDV2 in: Las Vegas (Clark County).
April – May 2020 Colorado – Domestic and wild rabbits died of RHDV2 in these counties: Alamosa, Costilla, El Paso, Prowers.
April – May 2020 Texas – Domestic and wild rabbits died of RHDV2 in these counties: El Paso, Hamilton, Hockley, Hudspeth, Jeff Davis, Lampasas, Lubbock, Midland, Pecos, Randall, Terrell.
March – May 2020 Arizona – Domestic and wild rabbits died of RHDV2 in these counties: Apache, Cochise, Coconino, Graham, Greenlee, Maricopa, Mohave, Navajo, Pima, Pinal.
March – May 2020 New Mexico
– Domestic and wild rabbits died of RHDV2 in these counties: Bernalillo, Chaves, Cibola, Curry, Dona Ana, Eddy, Grant, Lincoln, Luna, McKinley, Otero, Sandoval, Santa Fe, Sierra, Socorro, Torrance, Valencia.

Mexico

May 2020 Durango – Domestic and wild rabbits died of RHDV.
May 2020 Coahuila – Domestic rabbits died of RHDV.
The state of Coahuila shares its northern border with Texas.
May 2020 Baja California – Domestic rabbits died of RHDV.
The state of Baja California shares its northern border with California and north-eastern border with Arizona.
May 2020 Baja California Sur – Domestic rabbits died of RHDV in: Mulege.
April – May 2020 Sonora – Domestic and wild rabbits died of RHDV in: Caborca, Cajeme, Hermosillo, Moctezuma.
The state of Sonora shares its northern border with Arizona and the western corner of New Mexico.
April – May 2020 Chihuahua
– Domestic and wild rabbits died of RHDV in: Ahumada, Aldama, Allende, Camargo, Chihuahua, Delicias, Jiménez, La Cruz, López, and Nuevo Casas Grandes.
The state of Chihuahua shares borders with New Mexico to the North, and Texas to the East.

2020 New York

3/3/20 Manhattan, New York City (NY) – 11 rabbits in a vet hospital died of RHDV2.

2018-2020 Pacific Northwest
(Washington State, BC Canada)

The Center for Bird & Exotic Animal Medicine (Bothell, WA) successfully imported the Filavac RHDV1 & RHDV2 vaccine. Washington residents with rabbits, especially those in Clallam or Island Counties, should inquire about vaccine pricing and scheduling with CBEAM.

1/6/20 Clallam County, WA
 – 3 dead rabbits tested positive.
11/7/19 Whidbey Island, WA
– a domestic stray rabbit tested positive, and the Washington State Dept of Agriculture issued a quarantine on rabbits entering/leaving Whidbey Island.
9/23/19 San Juan Island, WA (San Juan Islands) –
2 domestic rabbits that had direct contact with stray/feral rabbits died from RHDV.
9/23/19 Saanich (Vancouver Island), BC – Canada – two stray/feral rabbits died, confirmed RHDV.
7/9/19 Orcas Island, WA (San Juan Islands) –
A pet rabbit died from RHDV2. No other rabbits are on the property.
6/21/19 Vancouver, BC – Canada – Several pet rabbits in a downtown Vancouver apartment died from RHDV.
4/10/19 Vancouver Area, BC – Canada – Four stray domestic rabbits in Parksville died from RHDV2.
3/2/18 Vancouver Area, BC – Canada – An outbreak of RHDV2 was reported starting in February in the Nanaimo area on Vancouver Island in British Columbia, Canada, with cases on the Canadian mainland in the Vancouver, BC area. The strain of the virus is RHDV2, closely matching the virus from an outbreak in a rabbit farm in Navarra, Spain in 2011. Canadian vets worked together and imported a European vaccine. According to the Ministry of Agriculture, no new RHDV2 cases were reported from May 2018 – March 2019.

Dr. Adrian Walton at Dewdney Animal Hospital in Maple Ridge, British Columbia, Canada coordinated with vets around Vancouver Island/BC to import vaccines for their patients. BC veterinarians who would like to join in vaccine order coordination, please email Dr. Walton.

How RHDV Is Spread

RHDV is highly contagious. It can be spread by:

  • Contact of a rabbit with inanimate objects contaminated by the virus (i.e. fomites). These objects include clothing, shoes, and car and truck tires.
  • Direct contact of a rabbit with an infected rabbit or the urine or feces of an infected rabbit.
  • Contact with rabbit products such as fur, meat or wool from infected rabbits.
  • Insects (including flies, fleas, and mosquitoes), birds, rodents, predators, and other pets (cats and dogs) are known to spread the virus by acting as indirect hosts or fomites. They can transport the virus from an infected rabbit to a healthy rabbit.
  • Humans can spread the virus to their rabbits if they have been in contact with infected rabbits or in contact with objects contaminated by the virus, including feces from an infected rabbit.
  • Ingesting virus-contaminated food or water.
  • Read the results of a 2017 survey of cases of rabbits who died of RHDV, to better understand risk factors, undertaken by veterinarian Dr. Frances Harcourt Brown.

How to Protect Your Rabbits

Biosecurity measures are essential to protect your rabbit in an outbreak, even if they are vaccinated. Here’s a handout you can share.

  • House your rabbits indoors. We strongly recommend that rabbits be kept indoors, or in enclosed environments, and not allowed outdoor playtime. Rabbits who live outdoors and those who exercise outdoors are at greater risk of contracting this disease.
  • Wash your hands thoroughly before handling your rabbits, particularly when you come home from places where other rabbits may have been, or where people who have been in contact with rabbits may have been, including feed stores, pet stores, fairgrounds, humane societies, etc.
  • Adopt a “no shoes in the house” policy, or keep your bunnies from running in high traffic areas of your home.
  • Trim your rabbit’s nails and groom them at home. Learn how to trim your rabbit’s nails and groom them at home, instead of taking them to a rescue or vet’s office, which are higher-risk locations.
  • Change your clothes and wash your hands after handling or coming in contact with other rabbits. Wash these clothes twice in hot water and dry in the dryer before wearing around your rabbit.
  • Don’t let your rabbit come into physical contact with other rabbits from outside your home, for example, “hoppy hour” or “bunny playground” activities.
  • If you volunteer at a shelter in an area with an outbreak, have special clothes and shoes that you wear only at the shelter. You may want to wear shoe covers or plastic bags over your shoes, secured with a rubber band. When you leave the shelter, remove the bags and dispose of them before you get into your car, making sure not to touch the outside of the bag. Follow clothes laundering instructions above, and shoe disinfecting instructions below. This protects the shelter rabbits as well as your own. The same considerations apply to anyone who sees rabbits at work and also has rabbits at home.
  • To disinfect shoes that may have been contaminated, place the shoes in a bath containing one of the below disinfectants. The shoes must be in contact with the disinfectant for the required contact time, during which time the disinfectant must remain wet. Be sure to read the label instructions for contact time for your disinfectant. Merely spraying shoes with disinfectant and leaving them to dry is not effective.
  • Use an effective disinfectant for this virus. Clean the item first, then disinfect. Read all disinfectant instructions and safety information provided by the manufacturer before using. Ask your veterinarian about how to obtain these:
    • accelerated hydrogen peroxide (Prevail, Rescue wipes or solution (formerly “Accel”), and Peroxigard)
    • sodium hypochlorite, household bleach (1:10 dilution = 1.5c bleach (12oz) in 1 gallon water)
      • organic matter inactivates bleach, so be sure the item is thoroughly cleaned with soap and water before disinfecting
      • Check the label on the bleach to make sure it is intended for disinfection, and not expired
      • Never mix bleach with other cleaning products
      • Animals must be removed from the area when bleach is used
      • Wear gloves when handling bleach, and use in a well-ventilated area
      • Once diluted, bleach loses efficacy after 24 hours
      • Wet contact time must be maintained on the surface for at least 10 minutes
      • Following disinfection, bleach should be rinsed off and surface dried before animal contact
    • potassium peroxymonosulfate (1% Virkon S, Trifectant)
    • substituted phenolics
  • Disinfect objects using one of the disinfectants above. Remember it must stay in contact with the item and remain wet for the required contact time of the disinfectant.
  • Know your sources of hay and feed and if they are near areas of any outbreaks.
  • Do not feed plants, grasses, or tree branches foraged from outside in areas where there is an outbreak.
  • Minimize insects in your home by installing window and door screens. Eliminate mosquitoes and flies from your home.
  • Use monthly flea treatment (Revolution or Advantage II are safe for rabbits. NEVER use Frontline on rabbits) for rabbits and cats and dogs, in an area with an outbreak, especially if any pets in the home go outside.
  • Keep cats indoors, so they can’t bring in the virus from outside.
  • Homes with dogs and rabbits: Keep dogs on-leash outside, so they don’t directly interact with wild rabbits (alive or deceased). Consider having your dog wear booties outside, or washing dogs’ paws when coming inside. Designate separate areas in your home for your dog and block dog access to areas where your rabbits live or exercise.
  • Quarantine any new rabbit for at least 14 days. Always handle quarantined rabbits last, and keep all supplies for them separate from your other rabbit’s’ supplies.
  • If you see a dead rabbit outside do not touch them. Contact state wildlife officials if it appears to be a wild rabbit. By reporting any dead rabbits seen outside, you will help protect domestic rabbits, as we will know where the disease is spreading.

Vaccination

Availability of Vaccines

  • Vaccinations are generally available in countries where the disease is endemic (the disease is regularly found there).
  • There is no vaccine currently widely available to vets in the US or Canada.
    • Canadian vets in British Columbia near Vancouver and Washington state vets near the northern border have successfully worked with regulatory agencies and have gotten special permission to import European vaccines.
    • May 2020: Some rabbit-savvy veterinarians in states affected by the Southwest outbreak are importing vaccines for their rabbit patients. If you live in one of these states, please contact your veterinarian to inquire about vaccination.
  • Veterinarians seeking to import vaccine in an area with an RHDV outbreak must have a USDA-accredited vet reach out to their State Veterinarian.
  • Currently, State Veterinarians/USDA is requiring a documented case of RHDV in their state before approving special import permits for the vaccine.

Vaccine Info for Veterinarians

About the Vaccines

Recommended Protocols for Animal Shelters and Rescue Facilities

What You Can Do

Educating yourself and others about RHDV is one of the best ways to help protect your rabbits. Don’’t panic, but get involved on spreading the word to others in the rabbit community.

Educate Yourself

  1. The Center for Food Security & Public Health and the Institute for International Cooperation in Animal Biologics: “Rabbit Hemorrhagic Disease
  2. World Organization for Animal Health: “Rabbit Haemorrhagic Disease
  3. USDA’s Animal and Plant Health Inspection Service (APHIS) – “Rabbit Hemorrhagic Disease – Standard Operating Procedures: 1. Overview of Etiology and Ecology
  4. Rabbit Welfare Association and Fund – information for rabbit guardians in the UK and Europe.
  5. Data about each outbreak of RHDV globally is reported in the World Organization for Animal Health’s WAHIS Interface.
  6. Dr. Frances Harcourt-Brown’s Rabbit Haemorrhagic Disease and its Variants (Lagoviruses)

Educate Others

Informing veterinarians, shelters, pet stores that sell rabbits, and fellow rabbit lovers about RHDV is important to helping to protect all rabbits. You can print these materials.

Report Sudden Deaths and Dead Wild Rabbits to Protect Rabbits from RHDV

Unexplained and suspicious rabbit deaths, especially when they occur in clusters of several rabbits dying in a short period of time, should be reported to your local veterinarian. All veterinarians are instructed to report any suspicious deaths to the State Veterinarian, and testing may be performed. This is very important to prevent the spread of this awful disease.

Domestic Rabbits: If you suspect that you have a possible case of RHDV, do not bury the body or take it out of the house, but call your vet to ask what to do.
Wild Rabbits: Contact state wildlife officials if you see dead wild rabbits – do not touch them.

Concealing an infected rabbit or knowledge of a RHDV infection sentences many other rabbits to death.

What is the Government Doing?

USDA-APHIS’s Center for Veterinary Biologics can issue a special permit for the import of a vaccine that is not licensed in the US. The State Veterinarian and USDA’s Area Veterinarian in Charge (AVIC) provide input in the decision.

Individual State Veterinarians will be the ones to decide what protocol to follow in event of an outbreak; however, it is likely they will invite APHIS to participate with them to handle an outbreak.

The USDA’s Foreign Animal Disease Diagnostic Laboratory (FADDL) in New York is the only lab in the country that tests for RHDV.

RHDV is a disease that is mandatory for veterinarians to report to their State Veterinarian or USDA Area Veterinarian in Charge, and all cases are reported to the World Organization for Animal Health (OIE).

House Rabbit Society Chapter Managers and leaders of other rabbit rescue groups should also contact their veterinarians and their State Veterinarians. The state authorities should know that there are concerned companion rabbit caregivers and rabbit rescues in your state whose interests must be included in policy making. We need to make sure our rabbit companions are not forgotten.

Past US Outbreaks 2000-2018

12/7/2018 Clover Township, PA40 pet rabbits in a barn died of RHDV1. This type 1 virus is a different strain than the 2018 RHDV2 cases in Ohio and Canada.

9/19/2018 Medina County, OH – Four pet rabbits on a single property died of RHDV2, the first case of RHDV2 in the US.

2/2010 Pine County, MN: 25 domestic rabbits died of RHDV1. The home supplied rabbits to a wildlife center, as food for predators. Feed contamination was the suspected source of RHDV1.

6/7/2005 Evansville, IN: Nearly 100 domestic rabbits died of RHDV1 at a home where rabbits were bred to sell to reptile owners as food for snakes. Surviving rabbits were euthanized, per State regulations. Less than 12 rabbits were recently purchased from an open market in Kentucky, no cases of RHDV1 were located in Kentucky.

12/11/2001 – Queens, NY: RHDV1 at an exotics animal facility in Flushings, NY that is open to the public. The suspected source of RHDV1 was rabbit meat imported from China.

8/17/2001 – Utah County, UT & Mercer County, IL:  The USDA confirmed RHDV1 at a rabbitry in Utah. A Mercer County, IL premises received 72 rabbits from the infected Utah premises, and those rabbits tested positive for RHDV1. Over 3,000 rabbits were euthanized.

4/10/2000 – Crawford County, IA: The first confirmed case of RHDV1 in the United States. 25 of 27 rabbits at a rabbit breeder’s property died, the remaining 2 were purchased and euthanized by the state.

HRS Policies and Guidelines Regarding RHDV

The following set of standards describes House Rabbit Society’’s policies regarding RHDV as well as recommended measures that should be taken to prevent outbreaks of this disease and actions to be taken in the event of an outbreak. We must respond quickly if an outbreak occurs. It is important that HRS members cooperate and follow federal, state, and local governmental agency directions with regard to epidemic issues, such as RHDV.

HRS Policies Regarding RHDV

  1. The role of HRS regarding this issue will be to provide support to the public by collecting, evaluating, and disseminating information on RHDV.
  2. The value of companion rabbits is immeasurable, and this must be considered in policy conditions concerning RHDV control.
  3. HRS recognizes the legal and ethical responsibility to report cases of this virulent disease and does not condone concealing this information from authorities.
  4. HRS shall not accept rabbits from areas where RHDV is endemic without a negative blood test and a 14-day quarantine.
  5. HRS shall not release membership or adoption records to authorities.
  6. HRS may appeal, on behalf of its members, any agency’’s decision to recommend euthanasia for exposed companion rabbits in favor of less drastic measures such as strict quarantine and serology.
  7. HRS will provide guidelines to protect rabbits during an outbreak.
  8. HRS volunteers shall follow the below-listed standards of practice recommended by HRS as to specific issues/topics, as well as those that from time to time shall be issued by HRS.

HRS General Guidelines Regarding RHDV

Guidelines to protect rabbits in an affected area during an outbreak:
  1. Limit contact (as much as possible) with places where rabbits might be found, including breeders, shows, pet stores, state and county fairs, veterinary offices, homes, animal shelters, and wild rabbit habitats.
  2. Disinfect one’’s person and items –following approved procedures –when contact with such an area is unavoidable.
  3. Follow quarantine procedures as directed by the regulatory agency.
  4. If under mandatory quarantine by a regulatory agency, all rabbit movement into and out of the premises (including adoptions, purchases, exhibitions, sales, grooming, and nonessential veterinary care) should cease until the quarantine is over.
  5. Seek veterinary evaluation of any unexplained rabbit death.
  6. Quarantine any rabbit who MAY have been exposed to RHDV –or its vectors– for 14 days; the quarantine for an individual rabbit may only be lifted if the rabbit tests seronegative (i.e., a blood test for RHDV antibodies is negative).
Guidelines to protect rabbits after an outbreak:
  1. Disinfect affected premises following approved procedures.
  2. Allow no new rabbits on the premises for 12 weeks.

Policy & guidelines approved by the National HRS Board of Directors April 28, 2000 and April 23, 2020