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Herpesviruses

Herpesviruses. September 9,14, 2010. Shanthi and Kumari, December 1993 –April 1995. Smithsonian National Zoological Park, Washington. The elephant herpesvirus Richman et al. 1999. Science 283:1171. The case of the elephant herpesviruses (Richman et al. 1999. Science 283:1171).

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Herpesviruses

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  1. Herpesviruses September 9,14, 2010

  2. Shanthi and Kumari, December 1993 –April 1995 Smithsonian National Zoological Park, Washington

  3. The elephant herpesvirusRichman et al. 1999. Science 283:1171

  4. The case of the elephant herpesviruses (Richman et al. 1999. Science 283:1171) Fatal hemorrhagic Disease in Asian elephants African elephant herpesvirus (“cold sores”) Asian elephant herpesvirus (“cold sores”) Fatal hemorrhagic Disease in African elephants

  5. Viruses with ds DNA genomes Papovaviridae bovine herpesvirus-1,2 equine herpesviruses -1,4 Adenoviridae porcine cytomegalovirus Herpesviridae malignant catarrhal fever virus Poxviridae African swine fever virus

  6. Alphaherpesvirinae(BHV-1, EHV-1,4, FelineHV, CanineHV) Grow rapidly Latency in sensory neurons Betaherpesvirinae Cytomegaloviruses (large balloon-like cells) Grow slowly Latency in salivary glands, kidneys, lymphocytes Gammaherpesvirinae(malignant catarrhal fever virus) Lymphoproliferative diseases Latency in lymphoid cells Herpesviridae

  7. Structure nucleocapsid envelope tegument glycoproteins (gB, gC…gL)

  8. Productive and latent infections

  9. Latency and Reactivation Viral DNA IE genes (regulatory) E genes (enzymes) L genes (structural) LAT reactivation stress immunosuppression corticosteroids cAMP

  10. Bovine herpesviruses

  11. Infectious bovine rhinotracheitis Disseminated fatal disease of newborns Abortions Genital lesions Encephalitis BHV-1(IBR virus)

  12. establishment of latency (infection for the first time) Infection in the animal Infection of replication in reactivation susceptible animal epithelial cells from latency replication in epithelial cells (rhinotracheitis) systemic cell-associated spread infection of the fetus encephalitis -> abortion

  13. Clinical and immunological parameters

  14. abortions encephalitis fatal disease in newborn calves Shipping fever (M. hemolytica, P. multocida) Bronchopneumonia -> fibrinous pleuropneumonia Complications of BHV-1 infection

  15. environmental crowding animals from different sources stress host-virus paralysis of mucociliary escalator release of iron and nutrients increased colonization immunosuppression Factors contributing to shipping fever

  16. virus isolation immunofluorescence immunohistochemistry PCR serology virus neutralization ELISA Diagnosis of BHV

  17. modified-live (attenuated) intra nasal intra muscular inactivated intra muscular Vaccination against BHV-1

  18. Equine alpha herpesviruses 5 other known herpesviruses

  19. Immunologically related Respiratory disease EHV-1causes abortions, neurological disease Immunity short lived Reinfection or reactivation EHV-1 and EHV-4

  20. Incubation period (1-10 days) Primary infection in young horses Biphasic fever Nasal discharge, cough Uncomplicated cases -> complete recovery 1-2 weeks EHV-1 and EHV-4 (respiratory disease)

  21. EHV-1 associated disease Acute respiratory disease in young horses Abortions (3rd trimester but can also occur at other times) Myeloencephalopathy (EHM)

  22. EHV-1 associated neurological disease - An emerging disease ?

  23. often but not always associated with respiratory disease often several horses sudden onset rapid progression, early stabilization ataxia, paresis, urinary incontinence, cystitis little evidence of viral replication in neural tissues (immune mediated?) vasculitis, thrombosis, hemorrhages (See EHV-1 Consensus Statement. J Vet Int Med. 2009. 23:450-461) Myeloencephalopathy by EHV-1

  24. Risk factors for EHV-1 myeloencephalitis • Viral (Nugent et al. 206. J. Virol 80:4047 • N752D mutation • Host (Goehring et al. 2006. J. Vet. Int. Med. 20:601) • sex - female • age - > 3 yrs • season - fall, winter • fever • breed - Hispanic, Standardbred, Draught

  25. Goodman et al. 2007. A point mutation in a herpesvirus polymerase determines neuropathogenecity. PLoS Pathogen. 3(11):e160.doi.1371

  26. Viraemia by neuropathogenic and non-neuropathogenic EHV-1 Allen and Breathnach 2006. Eq Vet Jn 38:252

  27. third trimester most likely few weeks to several months after respiratory outbreak abortion storms EHV-1 abortions

  28. Pathogenesis of abortion viraemia endometrial endothelial cell infection endometrial vasculitis and thrombosis extensive infarction: virus negative fetus

  29. Pathogenesis of abortion viraemia endometrial endothelial cell infection endometrial vasculitis and thrombosis extensive infarction: virus negative fetus limited infarction: virus positive fetus

  30. management vaccines short-lived immunity (mares - 5,7,9 months of gestation) reduce severity but do not prevent no vaccines licensed to prevent encephalomyelitis Prevention of EHV-1 disease

  31. Diagnosis • Virus isolation • PCR • Type 1 vs 4 • D752 vs N752 • serology

  32. Prevention and Control

  33. Other herpesviruses • alpha herpesviruses • porcine herpesvirus 1 (pseudorabies/Aujeszky’s disease) • Canine herpesvirus • Feline herpesvirus • Marek’s disease • beta herpesviruses • porcine cytomegalovirus • gamma herpesviruses • malignant catarrhal fever

  34. porcine herpesvirus • endemic in most parts of the world - Canada considered free (reportable disease) • wide host range • pigs • asymptomatic • abortions • fatal disease in new born piglets • respiratory, neurological • other species

  35. canine herpesvirus • wide-spread, usually asymptomatic • generalized fatal disease in puppies (fading puppy syndrome) • Ocular (Ledbetter, 2009. Vet Ophthalmol. 12:242-7) • hypothermia • no vaccine in N. America

  36. feline herpesvirus • feline rhinotracheitis • wide spread in catteries • respiratory infections • abortions - no direct viral involvement • vaccines

  37. Marek’s disease • lymphoproliferative, neurological disease of young chickens • unilateral paralysis, ataxia due to infiltration of spinal nerves • involvement of iris, skin • stable in feather follicle dander

  38. beta herpesvirus - porcine cytomegalovirus • asymptomatic if endemic in herds • in susceptible herds • inclusion body rhinitis • fetal death • runting, poor growth in young piglets

  39. malignant catarrhal fever (gamma herpesvirus) other ruminants ? other species malignant catarrhal fever

  40. clinical signs in susceptible species • peracute • high fever, diarrhoea, death in 1-3 days • acute • fever, depression, enlarged lymph nodes, serous nasal discharge, erosive lesions, corneal opacity, high mortality • chronic form

  41. acute MCF

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