RABBIT HEMORRHAGIC DISEASE VIRUS -USA (INDIANA)(03): OIE
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A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases
oie international


Rabbit Haemorrhagic Disease in the United States of America

(Date of previous outbreak of rabbit haemorrhagic disease in the United
States of America reported to the OIE: 2001).

Immediate notification report

Information received on 13 Jun 2005 from Dr Peter Fernandez, Associate
Administrator, Animal and Plant Health Inspection Service (APHIS), United
States Department of Agriculture (USDA), Washington, DC:

Report date: 13 Jun 2005.

Reason for immediate notification: re-occurrence of a listed disease or infection in a country or zone/compartment following a report declaring the outbreak(s) ended.

Precise identification of agent: calicivirus.

Date of first confirmation of the event: 7 Jun 2005.

Date of start of the event: 27 May 2005.

Clinical disease: yes.

Nature of diagnosis: clinical and laboratory.

Details of the outbreak:
First administrative division: Indiana State
Lower administrative division: Vanderburgh county
Type of epidemiological unit: farm
Name of the location: Evansville
Date of start of the outbreak: 27 May 2005
Species: lep
Number of animals in the outbreak: 200
susceptible cases: 96
deaths: 96
destroyed: 104
slaughtered: 0

Description of affected population: the premises is a private residence that maintains and sells rabbits to private citizens as a food source for their pet snakes. Occasionally a rabbit may be sold as a pet to the general public.

Diagnosis:
Laboratory where diagnosis was made : Foreign Animal Disease Diagnostic
Laboratory
Species examined: lep
Diagnostic tests used:
- antigen ELISA(1);
- electron microscopy;
- antigen ELISA(1);
- electron microscopy;- PCR(2).

Date: 7 Jun 2005
Results: positive
Source of outbreak or origin of infection: unknown or inconclusive.

Control measures
A. Undertaken:
- stamping out;
- quarantine;

B. To be undertaken: disinfection of infected premises/establishment(s).
Treatment of affected animals: no.
Vaccination prohibited: yes.

Other details/comments:

- A Foreign Animal Disease investigation was initiated on 3 Jun 2005 on a premises that raises rabbits primarily for sale to reptile owners as a food source for their pet snakes.

- Approximately 40 rabbits had died during the 10 days prior to the investigation.

- The owner had recently purchased several rabbits at a "flea-market" in Kentucky and introduced them into the herd.

- An epidemiological investigation has begun in Kentucky. There have been no additional reports of illness in either Indiana or Kentucky.

- The affected area is being cleaned and disinfected following humane disposal of all the rabbits on the premises.

- APHIS, Veterinary Services, the Indiana Board of animal Health and the Kentucky Department of Agriculture are working together to address this situation.

(1) ELISA: enzyme-linked immunosorbent assay
(2) PCR: polymerase chain reaction

--
ProMED-mail


[see also:
Rabbit hemorrhagic disease virus - USA (IN) (02) 20050613.1649
Rabbit hemorrhagic disease virus - USA (IN) 20050609.1603]
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Isn't it wonderful to see our OIE friends recommending the
use of RHD vaccine which is illegal in the USA and which is made by deliberately
infecting live rabbits then ripping out their livers to extract the RHD virus
which cannot be grown in the laboratory outside living animals
what a clean and wonderful safe vaccine to be promoting! ED Rabbit Info Service


RABBIT HEMORRHAGIC DISEASE VIRUS - USA (INDIANA) (02)
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A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases


Date: 13 Jun 2005
From: Antonio Lavazza

There are some points in the comments of the editor about rabbit hemorrhagic disease that, in our experience, seem to be not fully correct, and therefore, we would like to clarify them.

1) There is no definitive proof that a rabbit surviving the disease can act as a carrier of the virus for 4 weeks. If an animal is able to survive (5-25 percent of the infected), it is because there was a quick and efficient immune response. After 5-6 days post infection, a consistent immune response can be observed; no more viral circulating particles will be detected in the bloodstream using traditional diagnostic tests (i.e. ELISA), and the residual virions can be detected in a complex form only in the liver and spleen. What is surely true is that the virus is highly resistant in the environment and can persist at an infectious level for a very long time (several months). Therefore, even convalescent rabbits can act as vectors of the disease if, for example, their fur had been contaminated during the acute phase of the disease.

2) It is true that there is no specific treatment, but the use of hyper-immune serum in the initial phases of the disease can stop the infection. This is due to the fact that humoral immunity is most important in protecting rabbits from infection.

3) For the same reason, vaccination is absolutely effective in preventing both the infection and the disease. If animals are correctly vaccinated, there is no infection at all, and the virus is fully neutralized. In our experience, by applying a regular and correct vaccination plan, it is possible to prevent the diffusion of the disease in industrial farms, and it is also possible to obtain a full eradication in those infected units. Therefore, we believe that the "carrier" status of vaccinated/infected rabbits does not exist.

4) Indeed, it could be important and interesting to determine which viral strain is responsible for the outbreak and to check whether the available vaccine has been prepared with the same strain. In fact, it is known that there is at least one major antigenic variant of the virus -- called RHDVa (Capucci L., Fallacara F., Grazioli S., Lavazza A., Pacciarini L., Brocchi E. A further step in the evolution of rabbit hemorrhagic disease virus: the appearance of the first consistent antigenic variant. Virus Research, 1998, 58,115-126) -- that indeed was also responsible for the 1st outbreak in USA in 2000. This viral variant present some major antigenic changes in neutralizing epitopes, and therefore, even if there is quite a good level of cross immunity induced by the "classical" vaccine, the overall level of protection could be lower.

We hope that, with this short note, we have clarified some aspects of the disease.

--
Lorenzo Capucci and Antonio Lavazza
OIE Reference Laboratory for Haemorrhagic Diseases of Lagomorphs
Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna
(I.Z.S.L.E.R.) Via Bianchi 7/9 - 25124 Brescia (Italy)


[We appreciate The OIE reference laboratory clarifying these issues. Most of the comments from the previous ProMED-mail post were pulled directly from the USDA website:
, and it was clearly stated in the moderator's comment. What is especially interesting is that the OIE laboratory clarifies how the contaminated fur of a convalescing rabbit may be the source of infection for other rabbits. The USDA website does not make that clarification.

The vaccine mentioned above does not appear to have approval in the USA. - Mod.TG]

[see also: Rabbit hemorrhagic disease virus - USA (IN) 20050609.1603] ..............tg/msp/dk

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RABBIT HEMORRAGIC DISEASE VIRUS - USA (INDIANA)
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A ProMED-mail post

ProMED-mail, a program of the
International Society for Infectious Diseases


Date: 9 Jun 2005
From: ProMED-mail
Source: AHPIS/USDA official news release [edited]

Subject: Emergency Management Notice: Rabbit Hemorrhagic Disease
(Viral Hemorrhagic Disease of Rabbits) in Vanderburgh county, Indiana

On 7 Jun 2005, Rabbit Hemorrhagic Disease (RHD) was confirmed at a private residence in Vanderburgh county, Indiana by the Foreign Animal Disease Diagnostic Laboratory (FADDL) on Plum Island, NY. Specimens from these rabbits were positive for RHD antigen on ELISA, electron microscopy, and PCR.

A FAD (Foreign Animal Disease) investigation was initiated on 3 Jun 2005 on a premises that raises rabbits primarily for sale to reptile owners as a food source for snakes.

The investigation revealed that many of the 200 rabbits on the premises suddenly died during the past 10 days. Less than a dozen rabbits had recently been purchased from Kentucky and introduced into the herd.

An epidemiologic investigation has begun in Kentucky. The remaining rabbits are quarantined and will be euthanized and disposed of in accordance to State regulations. Cleaning and disinfection of the area will follow.

The Indiana epidemiological investigation is ongoing.

APHIS, Veterinary Services (VS), the Indiana Board of Animal Health, and the Kentucky Department of Agriculture are working together to address this situation.

VS (Veterinary Services) will assist the affected State in the euthanasia, cleaning, and disinfection of the premises. VS will continue to investigate reports of suspect RHD as part of its foreign animal disease surveillance program and will continue to diagnose suspect cases at FADDL.

The last known positive RHD case in the US occurred in a captive exotic animal facility in Flushing, New York in December 2001.

Please forward this information to other Federal, State, and industry counterparts as necessary.

--
ProMED-mail


[This is rabbit hemorrhagic disease virus (RHDV, family Caliciviridae).

From the USDA website:


Rabbit hemorrhagic disease (RHD) 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. RHD 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.

Clinical Signs
--------------
RHD 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 RHD ranges from 50 to 100 percent.

How RHD Spreads
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RHD 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 RHD 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.

Disease Prevention
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To protect against introducing RHD 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 RHD-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 RHD, isolation may help prevent spread to other rabbits. Clinical disease usually will be noticeable within 48 hours of infection.

If RHD 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 RHD, but will not eradicate the disease. Rabbits vaccinated against RHD may become infected but not show signs of disease, thereby allowing spread of the virus as a carrier. - Mod.TG]

[see also:
1999
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Viral hemorrhagic disease, rabbits - Cuba 19990403.0534
Viral hemorrhagic disease, rabbits - Cuba 19990326.0473
1998
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Rabbit viral hemorrhagic disease - Australia 19981124.2272
1997
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Rabbit viral hemorrhagic disease (14) 19970928.2048
Rabbit viral hemorrhagic disease (13) 19970924.2010
Viral hemorrhagic disease, rabbits - Cuba (03) 19970722.1539
Rabbit viral hemorrhagic disease (12) 19970712.1479
Viral hemorrhagic disease, rabbits - Cuba (02) 19970704.1435
Viral hemorrhagic disease, rabbits - Cuba 19970627.1391
Rabbit viral hemorrhagic disease (11) 19970221.0414
Rabbit viral hemorrhagic disease (10) 19970215.0380
Rabbit viral hemorrhagic disease (09) 19970203.0238
Rabbit viral hemorrhagic disease (08) 19970123.0138
Rabbit viral hemorrhagic disease (07) 19970121.0120
Rabbit viral hemorrhagic disease (06) 19970117.0096
1996
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Rabbit viral hemorrhagic disease (05) 19960711.1246
Rabbit viral hemorrhagic disease (2) 19960110.0044]
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EMAIL RECEIVED FROM A CONCERNED CITIZEN (NZ) JUNE 2005

Received 7th June 2005

Hi there
I was wondering if there is any new (in the 2000`s) articles or anything on RCD/RHD. As New Zealand Regional Councils (10 out of 13) are planning releases this winter (july) in New Zealand. We so far only have Auckland region being offered cheaper vaccinations ($7.00 per bun) for 3 hours On One Day by a group of vets which equals 4 vet clinics in Auckland. More up to date info would be great in our fight against RCD?RHD.

Thanks

A rare rabbit breed owner




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