58. Porcine epidemic diarrhoea, haemagglutinating encephalomyelitis of pigs. Flashcards

1
Q

PEDV History OCCURRENCE?

A

PEDV: Porcine epidemic diarrhoea,

History

  • 1971 England Type I (InDel)

‣ Feeders and fatteners

‣ No clinical signs in suckling piglets

  • 1976 Woods Type II (non-InDel)

‣ At all ages, piglets too

  • Europe, South-East Asia
  • Only pigs susceptible, usually less severe
  • After outbreak, the virus may either disappear or persist, it can become an endemic
  • After 2010, outbreaks in America and Asia
  • 2013 USA: similar symptoms, 2 types of pathogenicity
  • Mild diarrhoea in Europe
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2
Q

Pathogenesis, clinical signs and diagnosis of porcine epidemic diarrhoea?

A

Pathogenesis (similar to TGE)

  1. Viral intake: oronasal route
  2. Virus replication: epithelial cells of lungs or large intestine, occasional replication in crypts
  3. Viraemia
  4. It can get into milk but not foetus
  5. Virus shedding for 2 weeks
  6. Cause of death ➝ dehydration, metabolic acidosis, hyperkalaemia consequence of heart failure

Clinical signs

  • Profuse diarrhoea (depends on variant), vomiting
  • Stomach ache in older animals
  • After survival, the herd can be infection free or persistent carrier

Diagnosis

  • Clinical signs
  • IF, ELISA, Western blot, RT-PCR
  • Isolation with trypsin on Vero cells (other cells can be good too)
  • Replication in cells of bats ➝ change of host species
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3
Q

Prevention of Porcine epidemic diarrhoea?

A

Prevention

  • If survive Æ Passive immunization
  • Vaccine: Inactivated, Recombinant (under development), DNA (under development), Attenuated
  • (not used), Cross protection
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4
Q

Haemagglutinating encephalomyelitis coronavirus (PHEV) History and ethiology?

A

Haemagglutinating Encephalomyelitis (PHEV)

Nomenclature

  • Porcine haemagglutinating encephalomyelitis
  • Ontario disease
  • Vomiting-wasting disease

History

  • 1962 Canada, Ontario
  • 1969 England, Europe
  • 1978 Australia
  • Widespread, but clinical signs are rare, because they’re only seen in young piglets, but are protected by maternal

immunity ➝ appears sporadically

Etiology

  • Betacoronavirus
  • Unified antigen structure
  • No cross-reaction
  • CP
  • HE proteins
  • Natural host: swine
  • Artificial: rate and mouse can be diseased
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5
Q

Pathogenesis of Hpev?

A

Pathogenesis

  1. Viral intake: oronasal route
  2. Virus replication: asymptomatic replication in the respiratory tract, epithelial cells in the intestines (jejunum)
  3. Into CNS via peripheral nerves ➝ vomiting: sensor ganglion of N. Vagus
  4. Virus shedding until 8-10 days with nasal discharge, Antibody after 6-7 days, viraemia rare
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6
Q

Clinical signs?

A

Clinical signs

- V/W: few days after birth

‣ Loss of appetite, enervation

‣ Vomiting: yellow-green

‣ Constipation, fever for 2-3 days

‣ Hairy pigs (death between 1-2 weeks)

‣ Piglets unable to suck or swallow or throw up shortly after suckling

‣ Weight loss, dehydration

‣ Rarely 4-6 weeks old ➝ loss of appetite, enervation, vomiting, weakness, paralysis

  • Ontario disease: under 3 weeks

‣ Incubation: 4-7 days

‣ Shaking, arched back

‣ Bloated abdomen, unable to suck, loss of appetite, enervation

‣ Convulsions, rolling of eyes, trismus, pharyngeal paralysis

‣ Partial paralysis of limbs

‣ Cyanosis in end of legs

‣ Can recover without any remaining clinical signs

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7
Q

Pathology of HPEV?

A

Pathology

  • Piglets ➝ weight loss, dehydration, chronic cases: enlarged stomach
  • Histology: non-purulent inflammation of grey matter of brain and spinal cord, mainly in brain stem and first part of

spinal cord, in dorsal horns (ventral horns in Teschovirus infection)

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8
Q

Diagnosis, DD and prevention of HPEV?

A

Diagnosis

  • Direct virus detection: brain, lung, tonsils
  • Virus isolation: porcine kidney
  • IF, VN, HAI, RT-PCR

Differential diagnosis:

  1. Teschen-disease,
  2. Talfan-disease,
  3. Aujeszky disease

Prevention:

  • Surviving of sows: colostral immunity -> susceptible piglets do not get sick
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9
Q

Swine Acute Diarrhoea Syndrome Coronavirus (SADS-CoV)?

A

Swine Acute Diarrhoea Syndrome Coronavirus (SADS-CoV)

  • SADS-CoV or PEAV (porcine enteric alphacoronavirus)
  • From bats: 90 years ago
  • China 2017
  • Severe diarrhoea (experimental)
  • Young age: 5 day old
  • Mortality: 35-90%
  • Environmental is similar to SARS
  • SARS infected bats can have similar viruses like SADS-CoV
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10
Q

Porcine Deltacoronaviruse (PDCoV)?

A

Porcine Deltacoronaviruse (PDCoV)

  • Pigs with diarrhoea in USA 2014
  • Mixed with PEDV 10%
  • Bird origin
  • Mortality: 30-40%
  • Occurrence: USA, Canada, Mexico, Asia
  • Pathogenesis, clinical signs, pathology ➝ similar to PEDV
  • Diagnosis: IF, RT-PCR, Atg-detecting ELISA
  • Vaccine development in USA
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