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Subject: Update on RCD Date: Thursday, April 13, 2000 8:55 AM Hi all, Just a
few minutes ago information I posted information to the ARBA web site which was
faxed here this morning by Chris. A direct link to the USDA-APHIS web site has
also been supplied from our site for any wishing to use it. We are sending the
articles that were posted this morning in this email. You can view them on the
ARBA site also. Dick =================================================== Rabbit
Calicivirus Disease: Questions & Answers Q: What is rabbit calicivirus
disease? A: Rabbit calicivirus disease (RCD) is a highly infectious viral
disease of the European rabbit (Oryctolagus cuniculus). This is the species from
which all U.S. domestic and commercial rabbits are derived. American cottontail
rabbits and jackrabbits are not susceptible to infection. Q: Does this disease
affect people? A: No. Q: Does RCD affect other animals? A: It is not known to be
harmful to other animals. Q: What are the clinical signs of RCD? A: Rabbits die
suddenly within 6 to 24 hours of the onset of fever with few clinical signs.
Fever may be as high as 105 "F, but often is not detected until rabbits
show terminal clinical signs. RCD damages the liver, intestines, and lymphatic
tissue and causes terminal blood clots. The death rate ranges from 50 to 100
percent. Q: Is there a treatment? A: No. Q: Is there a vaccine? A: No vaccine is
legally available for use in the United States. Vaccines have been used in parts
of the world where the disease occurs in wild rabbits. Vaccination will often
reduce the number of rabbits dying from RCD, but will not eradicate the disease.
Rabbits vaccinated against the disease may become infected but not show signs of
disease, thereby allowing spread of the virus as a carrier. Q: How is RCD
spread? A: RCD is highly contagious. Many virus particles are passed in the
droppings of infected rabbits. The virus can then be spread on to the food of
healthy rabbits, infecting them. The virus can also be spread by contact with
rabbit products, rodents, and contaminated objects, such as cages, feeders, and
clothing. Contaminated objects may be a source of spread if not cleaned and
disinfected. Infected rabbits that recover may become carriers of the virus.
Recovered rabbits can shed the virus for at least 4 weeks after recovery. Q:
What precautionary measures can be taken to prevent RCD? A: To prevent the
spread of the disease, breeders should prevent contact between healthy rabbits
and infected rabbits and contaminated objects (e.g., cages, feeders, and
clothing). Where the health status of a rabbit is unknown, it should be kept in
mind that healthy looking rabbits can be in the early stage of disease and later
spread the disease. Additionally, recovered rabbits appear healthy but can be
carriers and spread the disease to other rabbits. Owners should be cautious and
isolate new rabbits and rabbits returning from shows for at least 5 days. If
rabbits were exposed to RCD, isolation may prevent the spread of the virus to
other rabbits. Clinical disease will usually be noticeable within 48 hours of
infection. Q: How should suspected cases of RCD be reported? A: Veterinarians
and rabbit owners who suspect a rabbit may have RCD should immediately contact
State or Federal animal health authorities.
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-------------------------------------------- Rabbit Calicivirus Disease Rabbit
calicivirus disease (RCD) is a highly infectious viral disease of the European
rabbit (Oryctolagus cuniculus). This is the species from which all U.S. domestic
and commercial rabbits are derived. American cottontail rabbits and jackrabbits
are not susceptible to infection. RCD is not known to harm humans or other
animals. Once the disease is introduced into a rabbitry, it can spread rapidly,
causing a high percentage of the rabbits to die. There is no treatment for the
disease. Recent History In 1984, RCD (also known as viral hemorrhagic disease of
rabbits) was reported for the first time in the People's Republic of China.
Since then, RCD has been reported in parts of Asia and Europe, including the
Czech Republic, Germany, France, Italy, Korea, and Spain. Investigations suggest
the disease spread from country to country through shipments of contaminated
rabbit meat and infected live rabbits. The first report of RCD in the Western
Hemisphere came in December 1988, when the disease was detected in domestic
rabbits in the Mexico City area. The outbreak was traced to a shipment of 18
metric tons of frozen rabbit carcasses from China that had been delivered to a
supermarket chain outside Mexico City. In February 1989, the Mexican government
began a control and eradication program that included quarantine of infected
farms, prohibition of movement or sale of rabbits, voluntary destruction of
diseased rabbits, and cleaning, disinfecting, and repopulating premises after a
2-month waiting period. The campaign was successful; there were no reported
cases in 1992. Mexico is the only country to succeed in eradicating RCD.
Clinical Signs RCD damages the liver, intestines, and lymphatic tissue and
causes terminal massive blood clots. The incubation period is about 24 to 48
hours. Predominantly, young adult and adult rabbits die suddenly within 6 to 24
hours of the onset of fever with few clinical signs. Fever may be as high as 105
F (40.5 C) but often is not detected until rabbits show terminal clinical signs.
Most animals appear depressed or reluctant to move in the final hours and may
show a variety of neurologic signs, including excitement, incoordination,
paddling, and opisthotonos (abnormal position of the head due to spasms of the
muscles at the top and back of the neck). Some affected rabbits may have a foamy
nasal discharge. The death rate for RCD ranges from 50 to 100 percent. How RCD
Spreads RCD is caused by a highly contagious virus. The disease can be
transmitted by contact with infected rabbits, rabbit products, rodents, and
contaminated objects, such as cages, feeders, and clothing. The virus also may
be carried short distances through moisture in the air. The risk of spread of
RCD is higher when confined rabbits are in close contact with each other.
Infected rabbits that recover may become carriers of the virus and may shed
virus for at least 4 weeks. Impact of Disease Spread If RCD was to become
established in the United States, it would have a significant impact on domestic
rabbits in North America. Producers of domestic rabbits receive about $10
million each year from the sale of rabbit meat and pelts in the United States.
The value of rabbits raised for research in the United States is about $15
million a year. This estimated value of $25 million a year does not take into
account several factors. One factor is the impact on availability of rabbits for
research and the production of medical diagnostic materials. Another factor not
taken into account is the value, both monetary and emotional, of the pet and
show rabbit industry. Disease Prevention To protect against introducing RCD into
the U.S. rabbit population, owners and producers should avoid contact between
their rabbits and imported rabbit meat, pelts, or other possibly contaminated
objects from RCD-affected countries. To prevent the spread of the disease if it
enters the United States, rabbit owners should prevent contact between healthy
rabbits and infected rabbits and contaminated objects (e.g., cages, feeders, and
clothing). Rabbits that appear healthy can be in the early stage of disease and
later spread the disease. Recovered rabbits also appear healthy but can be
carriers for at least 4 weeks and spread the disease to other rabbits. Owners
should be cautious and isolate new rabbits and rabbits returning from shows for
at least 5 days. If rabbits were exposed to RCD, isolation may help prevent
spread to other rabbits. Clinical disease usually will be noticeable within 48
hours of infection. If RCD is suspected, to prevent spread of the virus, rabbit
owners should clean and disinfect all equipment. After thorough cleaning, rabbit
breeders should use one of the following disinfectant solutions on equipment to
inactivate the virus: 2-percent 1-Stroke Environ (Steris Corporation, St. Louis,
MO), 0.5-percent sodium hypochlorite, or 10-percent household bleach. Vaccine No
vaccine is legally available for use in the United States. Vaccine has been used
in other countries. Vaccination often reduces the number of rabbits dying from
RCD, but will not eradicate the disease. Rabbits vaccinated against RCD may
become infected but not show signs of disease, thereby allowing spread of the
virus as a carrier. Report Possible Disease Veteriilarians and rabbit owners who
suspect a rabbit may have RCD should immediately contact State or Federal animal
health authorities. For more information, contact: U.S. Department of
Agriculture Animal and Plant Health Inspection Service Veterinary Services,
Emergency Programs 4700 River Road, Unit 41 Riverdale, MD 20737-1231 Telephone:
(301) 734-8073 Fax: (301) 734-7817
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