Rabbit Hemorrhagic Disease Virus (RHDV)

Oct 13, 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

About the Vaccines

Info for Veterinarians

Info for Animal Shelters & Rescue Facilities

What You Can Do

What Government is 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 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, but was thought to have originated in Europe, and there have now been confirmed cases in 40 countries, including in Europe, the Mediterranean, Africa, Asia, North America (Mexico, United States, Canada), Australia and New Zealand.

RHDV2, a new virus, 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 – it spread coast-to-coast in the rabbit population in 18 months (~3 million square miles, compared to United States’ ~3.8 million square miles) 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.

  • Incubation Period
  • Death Rate (Mortality)
  • Survivors: Rabbits who survive RHDV are carriers and shed the virus for at least 42 days, perhaps longer.
  • Asymptomatic Carriers: Some rabbits may have little to no symptoms of RHDV2 (subclinical/asymptomatic) but may shed virus for up to 2 months.
  • Transmission Routes: Rabbits are infected by oral, nasal/respiratory, or ocular exposure to the virus, or by blood-feeding insects.
  • Cause of Death: 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.
  • Durability of Virus: Rabbit calicivirus is a very hardy virus, remaining viable in the environment outside a host.
  • Seasonal Outbreaks: Where the virus has a reservoir in wild rabbits or feral domestic rabbits, seasonal outbreaks are expected year to year. In Australia, outbreaks start in fall and winter, peak in spring, and are mostly absent in summer. Seasonal fly abundance, as flies are a significant vector, may be linked with RHDV activity.
  • Treatment
    • There is no known cure for RHDV
    • RHDV 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

2020 New York

2018-2020 Pacific Northwest

2020 Southwest
(Arizona, California, Colorado, Nevada, New Mexico, Texas, Utah, 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.

Utah

June – August 2020
Wild and domestic rabbits died of RHDV2 in these counties: San Juan, Sanpete, Wayne (Teasdale area).

California

May – September 2020
Wild and domestic rabbits died of RHDV2 in these counties: Riverside, San Bernardino, San Diego, Orange, Los Angeles.

California has instituted a quarantine on rabbits entering the state, prohibiting rabbits entering from any state that has had a case of RHDV in the last year, unless they have a Certificate of Veterinary Inspection.

Nevada

April – July 2020
Domestic and wild rabbits died of RHDV2 in these counties: Clark (Las Vegas and Boulder City)

Colorado

April – September 2020
Domestic and wild rabbits died of RHDV2 in these counties: Adams, Alamosa, Arapahoe, Custer, Denver, El Paso, Elbert, Larimer, Mesa, Montezuma, Prowers, Pueblo, Weld.

Texas

April – June 2020
Domestic and wild rabbits died of RHDV2 in these counties: Brewster, Culberson, El Paso, Gaines, Hale, Hamilton, Hockley, Hudspeth, Jeff Davis, Kimble, Lampasas, Lubbock, Midland, Pecos, Potter, Presidio, Randall, Terrell, Ward.

Arizona

March – June 2020
Domestic and wild rabbits died of RHDV2 in these counties: Apache, Cochise, Coconino, Graham, Greenlee, Maricopa, Mohave, Navajo, Pima, Pinal, Yavapai.

New Mexico

March – July 2020
Domestic and wild rabbits died of RHDV2 in these counties: Bernalillo, Catron, Chaves, Cibola, Colfax, Curry, Dona Ana, Eddy, Grant, Lincoln, Los Alamos, Luna, McKinley, Otero, Roosevelt, Sandoval, Santa Fe, Sierra, Socorro, Taos, Torrance, Valencia.

Mexico

Vaccination is currently prohibited in Mexico. The government is currently developing a vaccine specific to this RHDV2 genotype. In the event of an outbreak, depopulation is required.

Zacatecas

June – September 2020
Domestic rabbits died of RHDV: Mazapil, Rio Grande, Villa de Cos.

Durango

May – July 2020
Domestic and wild rabbits died of RHDV: Canatlán, Delicias, Durango, Gómez Palacio, Lerdo, Nuevo Ideal, Santa Clara.

Coahuila

May 2020
Domestic rabbits died of RHDV: Francisco I. Madero, Matamoros, San Pedro, Torreón.
The state of Coahuila shares its northern border with Texas.

Baja California

May – July 2020
Domestic rabbits died of RHDV: Ensenada, Mexicali, Mulegé, Playas de Rosarito, Tecate.
The state of Baja California shares its northern border with California and north-eastern border with Arizona.

Baja California Sur

May – July 2020
Domestic rabbits died of RHDV: Comondú, La Paz, Mulege.

Sonora

April – May 2020
Domestic and wild rabbits died of RHDV: Caborca, Cajeme, Hermosillo, Moctezuma.
The state of Sonora shares its northern border with Arizona and the western corner of New Mexico.

Chihuaua

April – July 2020
Domestic and wild rabbits died of RHDV: Ahumada, Aldama, Allende, Camargo, Chihuahua, Coyame de Sotol, Cuauhtémoc, Delicias, Jiménez, Juarez, La Cruz, López, Meoqui, Nuevo Casas Grandes, Rosales, Rosario, Saucillo, Valle de Zaragoza.
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)

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 (Maple Ridge, British Columbia, Canada) coordinated with vets around Vancouver Island/BC to import vaccines. BC vets who would like to join in vaccine orders, please email Dr. Walton.

The Center for Bird & Exotic Animal Medicine (Bothell, WA) was the first US vet clinic to import the Filavac vaccine. Washington residents with rabbits, especially those in Clallam or Island Counties, should inquire about vaccination with CBEAM or their veterinarian.

How RHDV is Spread

RHDV is highly contagious. It can be spread by:

  • Direct contact: A rabbit comes into contact with an infected rabbit or the urine or feces of an infected rabbit.
  • Indirect contact
    • Human contact: People 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.
    • Inanimate objects: Contact of a rabbit with objects contaminated by the virus (i.e. fomites), including clothing, shoes, and car and truck tires.
    • Rabbit products: Contact with fur, meat or wool from infected rabbits.
    • Mechanical Vectors and Predators: 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 mechanical vectors, transporting the virus from an infected rabbit to a healthy rabbit. In Australia, flies who have been in contact with sick or dead rabbits are believed to be a primary source of long-distance viral transmission. RHDV can be excreted in the feces of predators who have consumed sick rabbits.
  • 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.
  • 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. See the USDA guidance for cleaning and disinfecting a RHDV2-contaminated premises. Ask your veterinarian about how to obtain these disinfectants.
    • accelerated hydrogen peroxide
      • Prevail, Rescue wipes or solution (formerly “Accel”), Intervention, and Peroxigard [on EPA list as “Oxy-1” wipe or RTU]
    • 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.
    • Avoid feeding hay grown, or stored outdoors, in an outbreak area. On farms and at many feed stores, hay bales are stored outdoors, or in barns that are open to insects, birds, rodents, cats, or other animals that could spread the virus.
    • If hay was grown in an outbreak area, ask if it was stored indoors in an environment secure from insects, birds, rodents, cats or other animals. If the hay is stored in packaging (for example, a cardboard box or plastic bag), you can ask how long the hay has been packaged.

      As the virus is no longer viable after 105+ days at room temperature (68F), hay that has been grown in an outbreak area but securely stored for longer than 4 months would minimize the risk. In areas with cooler temperatures, hay would need to be securely stored longer – RHDV lasts 225 days at 39F, so would need to be stored for 8 months to minimize the risk.
  • 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. Treat 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.
  • Don’t feed cats/dogs rabbit meat: Do not feed your dog or cat raw or freeze-dried rabbit meat – if there is virus in the rabbit meat, it could be spread to pet or wild rabbits by the dog or cat poop.
  • 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-July 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.

About the Vaccines

Info for Veterinarians

Info for Animal Shelters & Rescue Facilities

What You Can Do

Educating yourself and others about RHDV is one of the best ways to help protect rabbits. Don’’t panic. Get involved, spread the word to others in the rabbit community.

References

  1. Rabbit Hemorrhagic Disease and Other Lagoviruses (June 2020)
    The Center for Food Security & Public Health
    Institute for International Cooperation in Animal Biologics
    Iowa State University, College of Veterinary Medicine
    World Organization for Animal Health (OIE)
    United States Department of Agriculture (USDA)
  2. World Animal Health Information Database (WAHIS Interface)
    World Organization for Animal Health (OIE)
    Data about each outbreak of RHDV globally is reported here.
  3. Rabbit Haemorrhagic Disease (February 2009)
    World Organization for Animal Health
  4. Rabbit Hemorrhagic Disease – Standard Operating Procedures: 1. Overview of Etiology and Ecology (October 2013)
    USDA’s Animal and Plant Health Inspection Service (APHIS)
  5. Rabbit Viral Haemorrhagic Disease
    Rabbit Welfare Association and Fund
  6. Rabbit Haemorrhagic Disease
    Dr. Frances Harcourt-Brown

Educate Others

Informing veterinarians, shelters, pet stores that sell rabbits, and fellow rabbit lovers about RHDV is important in 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 Government is Doing

Federal

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

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

State

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

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.

In states with confirmed RHDV2 cases in wild rabbits or stray/feral domestic rabbits, the USDA has given permission to State Veterinarians to designate labs in that state for RHDV2 testing. These labs are using testing protocols provided by the USDA. As of July 2nd, 2020, labs have been designated in Colorado, California, and New Mexico.

California

California Department of Food and Agriculture (CDFA) has adopted a strategy of RHDV control, instead of RHDV eradication: “a control program (…) uses euthanasia sparingly and primarily in unique cases where the virus threatens protected populations of rabbits.”

Texas

Texas Animal Health Commission (TAHC): “The TAHC will not depopulate [euthanize] domestic, feral, or wild rabbit colonies where rabbits have been exposed and recovered from RHDV2.”

Utah

Utah Department of Agriculture and Food (UDAF): In the event of an outbreak, Utah will do a property-level quarantine “… the Utah State Veterinarian…is quarantining your facility for a minimum of 120 days. Your facility will only be released from quarantine once the State Veterinarian is satisfied that your facility does not pose a threat of spreading RHDV2 to wild or domestic rabbits within the state.

While under quarantine, no live rabbits, rabbit products (including fur and meat), or equipment are allowed to leave the property except under the express permission of the State Veterinarian.”

Washington

Washington State Department of Agriculture (WSDA): “WSDA will not depopulate domestic, feral, or wild rabbit colonies where rabbits have been exposed and recovered from RHD. Depopulation will do little to control the disease because the virus is present in the feral domestic rabbit population in affected areas.”

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

Past US Outbreaks 2000-2018

12/7/2018 Clover Township, PA – 40 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 one 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 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.
  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.
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, April 23, 2020, June 11, 2020.

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