Lapis ISSN 2398-2969

Viral hemorrhagic disease 2

Synonym(s): VHD2, Rabbit plague, Rabbit viral septicemia, Rabbit hemorrhagic disease (RHD), Rabbit viral disease (RHVD), Rabbit calici virus, HVD, New variant RHD, Variant RHD

Contributor(s): Richard Saunders, Vetstream Ltd

Introduction

  • Cause: Calicivirus, RHD strain 2.
  • Signs: sudden death with bleeding from nose/mouth or more vague and slower onset clinical signs.
  • Diagnosis: history, signs.
  • Treatment: supportive.
  • Prognosis: variable; lower mortality than RHD1.
  • VHD2 is a less acute onset than VHD1 virus infection with the European rabbit (Oryctyolagus cuniculus), as the only known host.
  • A similar virus occurs in hares (European Brown Hare Syndrome Virus - EBHSV) but no cross-communication between species has yet been recorded.
Print off the Owner factsheets on Viral Hemorrhagic disease- VHD and Vaccination- essential protection to give to your clients.

Pathogenesis

Etiology

  • VHD is a highly contagious calicivirus Calicivirus.
  • It is extremely stable and has been shown to persist up to 3 months on clothing. It has no antigenic relationship with any other calicivirus other than European Brown Hare Syndrome (EBHS) virus.
  • Transmission is horizontal by direct contact with excretions of infected rabbits. It can also be spread indirectly by aerosol exposure to contaminated fomites and mechanically via equipment, clothing, rodents and birds.
  • Insect vectors may also be implicated.
  • VHD1 Viral hemorrhagic disease 1 is extremely persistent in the environment, depending on the substrate and temperature. It can survive on organic material for 225 days at a temperature of 4°C/39.2°F, and 120 days at 22°C/71.6°F. VHD2 is likely to have similar properties.

Predisposing factors

General

  • The disease is extremely virulent in rabbits >2 months of age.
  • Poor nutrition, overcrowding and stress may predispose.

Specific

  •  In naïve animals with a lack of natural or vaccine induced immunity to the virus, morbidity and mortality approach 100%.

Pathophysiology

  • The virus targets the liver causing hepatic necrosis most likely caused by viral replication within hepatocytes.
  • Release of tissue thromboplastins from damaged hepatocytes initiates disseminated intravascular coagulation leading to widespread hemorrhage.

Timecourse

  • The virus has a longer incubation period and disease course, in total around 10-14 days as opposed to the 4-9 days seen with VHD1.

Epidemiology

  •  In the wild, the typical picture is a “hot-spot” of sudden deaths in a localized area. However, the clinical signs mimic trauma, some rabbits die underground and are not seen, and others are rapidly carried away by predators, and so the true incidence of the disease is likely to be significantly underestimated.
  • A similar issue exists with domestic rabbits. Death is often sudden, with no preceeding signs. The whole group may die, but, being small pets, they are often disposed of at home and the veterinary practice is unaware of outbreaks.
  • The infection runs out of hosts, and is carried by fomites or vectors to another site, often some considerable distance away, for the pattern to repeat.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Westcott D G & Choudhury B (2015) Rabbit haemorrhagic disease virus 2-like variant in Great Britain. Vet Rec 176 (3), 74 PubMed.
  • Abrantes J, Lopes A M, Dalton K P et al (2013) New Variant of Rabbit Hemorrhagic Disease Virus, Portugal, 2012–2013. Emerg Infect Dis 19 (11), 1900–1902 PubMed.
  • Le Gall-Reculé G, Lavazza A, Marchandeau S et al (2013) Emergence of a new lagovirus related to Rabbit Haemorrhagic Disease Virus. Veterinary Research 44, 81 PubMed.
  • Abrantes J, van der Loo W, Le Pendu J et al (2012) Rabbit haemorrhagic disease (RHD) and rabbit haemorrhagic disease virus (RHDV): a review. Vet Res 43, 12 PubMed.
  • Dalton K P, Nicieza I, Balseiro A et al (2012) Variant Rabbit Hemorrhagic Disease Virus in Young Rabbits, Spain. Emerg Infect Dis 18 (12), 2009-2012 PubMed.
  • Meredith A (2012) A vaccine against myxomatosis and RHD: a step forward for rabbit health. Vet Rec 170 (12), 307-308 PubMed.
  • Spibey N, McCabe V J, Greenwood N M et al (2012) Novel bivalent vectored vaccine for control of myxomatosis and rabbit haemorrhagic disease. Vet Rec 170 (12), 309 PubMed.
  • Le Gall-Reculé G, Zwingelstein F, Boucher S et al (2011) Detection of a new variant of rabbit haemorrhagic disease virus in France. Vet Rec 168 (5), 137-138 PubMed.
  • Ferreira P G, Costa-e-Silva A, Monteiro E et al (2004) Transient decrease in blood heterophils and sustained liver damage caused by calicivirus infection of young rabbit that are naturally resistant to rabbit haemorrhagic disease. Res Vet Sci 76 (1), 83-94 PubMed.
  • Marchandeau S, Bertagnoli S, Peralta B et al (2004) Possible interaction between myxomatosis and calicivirosis related to rabbit haemorrhagic disease affecting the European rabbit. Vet Rec 155 (19), 589-592 PubMed.
  • Campagnolo E R, Ernst M J, Berninger M L et al (2003) Outbreak of rabbit hemorrhagic disease in domestic lagomorphs. JAVMA 223 (8), 1151-1155, 1128 PubMed.
  • Abu Elzein E M & al-Afaleq A I (1999) Rabbit haemorrhagic diseases in Saudi Arabia. Vet Rec 144 (17), 480-481 PubMed.
  • Chasey D & Trout R C (1995) Rabbit haemorrhagic disease in Britain. Mammalia 59 (4), 599-603.
  • Chasey D, Lucas M H, Westcott D G et al (1995) Development of a diagnostic approach to the identification of rabbit haemorrhagic disease. Vet Rec 137 (7), 158-60 PubMed.
  • Donnelly T M (1995) Emerging viral diseases of rabbits and rodents - viral hemorrhagic disease and hantavirus infection. Semin Avian Exotic Pet Med 4 (2), 83-91 ScienceDirect.
  • Hillyer E V (1994) Pet rabbits. Vet Clin North Am Small Anim Pract 24 (1), 25-65 PubMed.
  • Chasey D (1994) Possible origins of rabbit haemorrhagic disease in the United Kingdom. Vet Rec 135 (21), 496-499 VetMedResource.
  • Fuller H E, Chasey D, Lucas M H et al (1993) Rabbit haemorrhagic disease in the United Kingdom. Vet Rec 133 (25-26), 611-613 PubMed.
  • Chasey D, Lucas M, Westcott D et al (1992) European Brown Hare Syndrome in the UK - a calicivirus related to but distinct from that of VHD in rabbits. Arch Virol 124 (34), 363-370 PubMed.
  • Chasey D & Duff P (1990) European Brown Hare Syndrome and associated virus particles in the UK. Vet Rec 126 (5), 623-624 PubMed.

Other sources of information

  • Esteves P J et al (2015) Emergence of Pathogenicity in Lagoviruses: Evolution from Pre-existing Nonpathogenic Strains or through a Species Jump? PLoS Pathog 11 (11), e1005087. Website: journals.plos.org.
  • Gavier-Widén D & Neimanis A (online) The emergence and spread of rabbit hemorrhagic disease type 2 virus (RHDV2) in Europe: a threat to wild rabbit populations. Wildlife Health Specialist Group. Website: www.iucn-whsg.org.
  • Harcourt-Brown F (online) About rabbit haemorrhagic disease and its variants (Lagoviruses). Veterinary Information about Rabbit Medicine and Surgery. Website: www. harcourt-brown.co.uk.
  • Saunders R (webinar) The latest on VHD/RHD 2 vaccination - what rabbit owners need to know! Website: therabbitvet.com.


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