HERPESVIRIDAE

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HERPESVIRIDAE

• PETER H. RUSSELL, BVSc, PhD, FRCPath, MRCVS
• Department of Pathology and Infectious Diseases,
  The Royal Veterinary College,
• Royal College Street,
• London NW1 OTU.
• E-mail Web site

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ObjectivesStudents should be able to

• Give 3 reasons why herpesviruses are difficult to
  control.
• Know the difference between immediate-early,
  early and late genes and their roles in disease
  and tumours.
• List the major diseases in each species of
  animals and the tissue-tropism of the causative
  virus

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Replication

• The uncoated double stranded DNA becomes a closed
  circle in the host nucleus
• Three types of genes are involved in replication

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Herpesviruses are bad news for 4 reasons.
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Virulence is associated with presence of a
thymidine kinase (tk) gene, so this is deleted
from genetically engineered vaccines eg to
Aujeskys virus. Tk acclerates new DNA synthesis
by salvaging thymidine from degraded DNA into
TTP. It has been widely used to select cells eg
hybridoma's or those which are expressing
recombinant vaccines see Russell and Edington,
page 99.
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Research. 3 growth areas
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The members of the herpesviridae according to
host and major disease patterns
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The members of the herpesviridae according to
host and major disease patterns
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The members of the herpesviridae according to
host and major disease patterns
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The members of the herpesviridae according to
host and major disease patterns
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The major members of the herpesviridae according
to host and major disease patterns
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The major members of the herpesviridae according
to host and major disease patterns
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The major members of the herpesviridae according
to host and major disease patterns
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The major members of the herpesviridae according
to host and major disease patterns
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The major members of the herpesviridae according
to host and major disease patterns
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The major members of the herpesviridae according
to host and major disease patterns
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Equid herpesvirus 1(1)

• This is the most common cause of abortion in
  mares in the U.K. It also causes respiratory
  disease and, more rarely, paresis

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Equid herpesvirus 1(2)

• This is the most common cause of abortion in
  mares in the U.K. It also causes respiratory
  disease and, more rarely, paresis

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Equid herpesvirus 4

• This virus cannot be distinguished from EHV 1 by
  polyclonal sera - but can be distinguished by
  mAbs, PCR probes and by RE profile. It is more
  prevalent than EHV 1 (by a factor of 2) in the
  U.K., but in the majority of cases it only causes
  respiratory disease.

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Bovid herpesvirus 1

• Pathogenesis
• Rhinotrachietis with lacrimation then
  lymphocyte-associated viraemia and then latency
  in cranial ganglia. Can cause 75 mortality of
  feed lot cattle with bronchpneumonia. Viraemia
  can spread to cause meningo-encephalitis,
  especially in calves, infectious pustular
  vulvovaginits and abortion.

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Bovid herpesvirus 2 (Bovine mammillitis virus)

• Moist, raised erosions/plaques on teats with
  spread to udder
• A zoonosis of milkers.
• Infection can be a perennial problem in winter

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Bovid herpesvirus 3

• (Malignant catarrhal fever virus)

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Suid herpesvirus 1

• Notifiable.
• Also known as Aujeszky's disease, pseudorabies,
  "mad itch".
• While this has been eradicated from mainland
  Britain by a pig levy and area eradication scheme
  it is still present in much of Europe and
  Ireland.

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• Canid herpesvirus 1

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Felid herpesvirus 1

• The virus is widespread within the feline
  population. It affects the upper respiratory
  tract but erosions affect the bronchii and
  interstital pneumonia can result. Latent
  infections can be reactivated during boarding..
  Infections are often concurrent with calicivirus
  and chlamydial infections.

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Herpes B Virus

• Monkeys. Asiatic (old world) monkeys (eg
  macaques and rhesus) are the natural hosts. In
  the wild only 10 of the population carry latent
  virus in ganglia/have antibodies but in captive
  colonies, where monkeys are kept at high density,
  the prevalence is frequently 60.
• The lesions in monkeys are oral focal erosions,
  very similar to cold sores of man. New world
  monkeys, like man, die with encephalitis and do
  not excrete salivary virus.

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Summary

• EHV1 is a disease not only of the resp tract but
  also causes abortion storms and paresis.
  Vaccines are not good and so the Jockey club has
  regs re isolation and transport after abortions
• IBR causes a spectrum of disease and live
  vaccines can reduce disease.
• Porcine herpevirus 1 is a notifiable disease
  which cause abortion in sows and some fatalies
  after encephalitis in piglets and fatal
  pseudorabies in carnovores and ruminants. It has
  been eradicated from GB, but not N.Ireland.
• Feline herpes can be reactivated during boarding
  to cause erosive lesions
• Herpesvirus B only causes oral lesions in
  monkeys, but causes a fatal encephalitis in man.