Download Rabbit hemorrhagic disease Norovirus

• Family Caliciviridae
Genus Vesivirus; species: swine
Lagovirus; species: Rabbit hemorrhagic
disease
Norovirus; species: Norwalk
Sapovirus; species: Sapporo
• Found in humans, rabbits, cattle, pigs, cats, chickens,
reptiles, dolphins, sea lions, walruses, foxes, etc.
• Single-stranded RNA, non-enveloped virus.
• Not very well studied because they do not grow in culture
and there’s no suitable animal model.
• Transmission is generally by the fecal-oral route, but can
also be transmitted via the respiratory route.
• Vaccinations reduce the appearance of clinical signs and
symptoms.
• Highly infectious
• High degree of genomic
plasticity
• RNA polymerase poor ability to
proofread resulting in mutations
• Virus responds rapidly to selected pressures in the
environment making it a very adaptable virus
• Replicates in the oral and respiratory tissues
• Worldwide distribution
• Direct contact is the main method
of infection.
• Shed in oronasal and conjunctival
secretions
• Transmitted indirectly via
contamination of the environment
• Incubation period of 2-6 days
• Shed the virus for 2 to 3 weeks
• Persists in the environment for several days to weeks, and
in some cases up to a year or more, depending on
environmental conditions
Common Clinical Signs:
Signs of Virulent Systemic Disease:
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• Cutaneous edema
• Ulcerative lesions on the skin/paws
• Crusted lesions on the nose, lips,
ears, eyes and footpads
• Alopecia
• Jaundice
• Respiratory distress
• Bruising
• Epistaxis – nose bleeds
• Bloody feces
• Multi-organ failure
• Death
Lingual and Oral ulcers
Sneezing
Clear nasal discharge
Fever
Anorexia
Salivation
Inflammation and Irritation of the
nasal tissue and oral cavity
• Lameness
Severe Clinical Signs:
• Pneumonia - difficulty breathing
• Depression
• Coughing
Supportive Treatment
Antiviral Therapy
IV or subcutaneous fluids
Ribavirin
Special diet and appetite
Feline Interferon
Stimulants
Immunoglobulins
Tube feeding
Broad spectrum
Antibiotics
Mucolytics
NSAIDS
Corticosteroids
Dental cleaning and tooth extractions
• Calicivirus causes
respiratory symptoms that
usually heal within 2-3
weeks
• Most clear the virus from
their systems within 30 days
• Some remain persistently
infected, and will continue to
shed the virus
• On rare occasions a highly
virulent strain of calicivirus
can progress to a systemic
form
• Part of the core vaccination protocol
suggested for cats
• Recommended at 8-9 weeks and 12
weeks of age
• Some kittens may need a third
booster at 16 wks (high risk situation)
• Adult cats of unknown immune status should also be
vaccinated (booster 2-4 weeks later)
• Herpes virus vaccination
• Nearly impossible to avoid a cat contracting this disease at
some point
• 2009 study by Jas et al.
• Tested 8-9 week old kittens known to be
pathogen free by challenge 1 week and 3-4
weeks after vaccination of an
inactivated FCV vaccine
• Efficacy of the vaccination was
comparable whether challenged
1 week or 3-4 weeks after vaccination
• Concluded the onset of protection occurred
within 7 days of vaccination
• Novel Calicivirus in
Michigan (MRCV)
• Hemorrhage, hepatic
necrosis and sudden death
• Highly susceptible = Domestic rabbits and
free-ranging European rabbits
• Unaffected = cottontail and hares
• Jan. 2001 - New Zealand White rabbitry,
65/200, 32.5% fatality
• MRCV distinct species from RHDV
• 1977 study by Prato et al.
• Tested 3 populations of wild
foxes for the presence of
neutralizing antibody to 4
different calicivirus strains
• Neutralizing activity was detected in
serum from 2 of the 3 populations
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1985, Rogue Reef off Oregon coast - first isolation
Transmission from marine to terrestrial species
Tagging operation led to isolation
Impact on species not assessed
however these disease agents
causes:
 Vesicular lesions
 Abortion
 Encephalitis
 Pneumonia
• Commonly cause acute gastroenteritis, nausea, vomiting
and diarrhea
• Virus multiplies within the small intestine
• Incubation time of 2 days
• Symptoms only generally last for 3 days
• Most calicivirus infections do not call for medical attention
• After infection, immunity is usually incomplete and
temporary
• Affects people of all ages
• Causes approximately 90% of epidemic non-bacterial
outbreaks of gastroenteritis around the world, commonly
called the “stomach flu”
• May be responsible for 50% of all foodborne outbreaks of
gastroenteritis in the US
• Hand washing is an effective method to reduce the spread
of pathogens, but alcohol rubs are not very effective
As there is no known cure for calicivirus, control is
essential.
Carcasses should be buried
While animals exposed to the
virus should be quarantined
or euthanized.
Sanitizing objects that have
come in contact with sick
animals can be done more
effectively by using bleach.
Bergin, I.L., A.G. Wise, S.R. Bolin, T.P. Mullaney, M. Kiupel, and R.K. Maes. 2009. Novel calicivirus
identified in rabbits, michigan, usa. Emerging Infectious Diseases, 15.12:1955-1962.
Jahnke, M., E.C. Holmes, P.J. Kerr, J.D. Wright, and T. Strive. 2010. Evolution and phylogeography of
the nonpathogenic calicivirus rcv-a1 in wild rabbits in Australia. Journal of Virology, 84.23:
12397-12404.
Jas, D., C. Aeberle, V. Lacombe, A.L. Guiot, and H. Poulet. 2009. Onset of immunity in kittens after
vaccination with a non-adjuvanted vaccine against feline panleucopenia, feline calicivirus
and feline herpesvirus. Veterinary Journal, 182.1:86-93.
Mencke, N., M. Vobis, H. Mehlhorn, J. D'Haese, M. Rehagen, S. Mangold-Gehring, & U. Truyen.
2009. Transmission of feline calicivirus via the cat flea (Ctenocephalides felis).
Parasitology Research, 105.1:185-189.
Prato, C.M., T.G. Akers, and A.W. Smith. 1977. Calicivirus antibodies in wild fox populations. Journal of
wildlife disease. 13.448-450.
Skilling, D.E., J.E. Barlough, E.S. Berry, R.F. Brown, and A.W. Smith. 1987. First isolation of a calicivirus
from the stellar sea lion (Eumetopias jubatus). Journal of Wildlife Diseases, 23.4:534-538.
Williams, E.S., T. Yuill, M. Artois, J. Fischer, and S.A. Haigh. 2002. Emerging infectious diseases in
wildlife. Revue Scientifique et Technique Office International des Epizooties, 21.1:139-157.