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HERPESVIRIDAE

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Latent infections can be reactivated during boarding. ... only 10% of the population carry latent virus in ganglia/have antibodies; but in ... – PowerPoint PPT presentation

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Title: HERPESVIRIDAE


1
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

2
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

3
Replication
  • The uncoated double stranded DNA becomes a closed
    circle in the host nucleus
  • Three types of genes are involved in replication

4
Herpesviruses are bad news for 4 reasons.
5
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.
6
Research. 3 growth areas
7
The members of the herpesviridae according to
host and major disease patterns
8
The members of the herpesviridae according to
host and major disease patterns
9
The members of the herpesviridae according to
host and major disease patterns
10
The members of the herpesviridae according to
host and major disease patterns
11
The major members of the herpesviridae according
to host and major disease patterns
12
The major members of the herpesviridae according
to host and major disease patterns
13
The major members of the herpesviridae according
to host and major disease patterns
14
The major members of the herpesviridae according
to host and major disease patterns
15
The major members of the herpesviridae according
to host and major disease patterns
16
The major members of the herpesviridae according
to host and major disease patterns
17
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

18
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

19
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.

20
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.

21
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

22
Bovid herpesvirus 3
  • (Malignant catarrhal fever virus)

23
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.

24
  • Canid herpesvirus 1

25
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.

26
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.

27
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.
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