Porcine Circoviruses

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Antigenicity

  • Two serotypes:
    • PCV1 is harmless
    • PCV2 is virulent, causing:
      • Post-weaning Multisystemic Wasting Syndrome (PMWS) in young pigs
      • Porcine Dermatitis and Nephropathy Syndrome (PDNS) in older pigs

Pathogenesis

PMWS:

  • Enlarged lymph nodes with lymphopenia as virus concentrates in germinal centers
  • Typically strikes weaners (8-12 weeks old)
  • Clinical signs:
    • Pale skin color
    • Jaundice
    • Enlarged lymph nodes and kidneys
    • Unthrifty appearance
    • Lameness
    • Respiratory disease
    • Occasional diarrhoea
  • Large range of differentials, particularly Swine Fever, African Swine Fever, Pasteurella, and colisepticemia
  • Mortalities can reach 40% in an outbreak; nationally range from 4-10% annually

PDNS:

  • Can follow PMWS
  • Seen in growers and finishers
  • Presents as an immune-mediated necrotising vasculitis
  • Extensive hemorrhages of kidneys and skin, especially in the scrotal region, accompanied by pyrexia

Epidemiology

  • Poor immune response
  • Transfer is orofecal and venereal
  • PCV2 is the most important widespread porcine virus:
    • Detrimental losses to the industry
    • Predisposes to secondary infection
    • Easily misdiagnosed

Diagnosis

  • Clinical signs
  • Confirmed by PCR for PCV2 nucleic acid
  • However, positives can show NO clinical signs
  • Easily confused with Classical Swine Fever

Control

  • No vaccines are available
  • Antibiotics to prevent secondary infection
  • Good ventilation, bio-security, and proper management
  • Passive antibody can be used in dire circumstances:
    • Viral serum from an adult pig and be injected peritoneally into piglets to stimulate a high anitbody response
    • Must be done by a vet and only within a single herd

Postweaning multisystemic wasting syndrome (PMWS)

Literature Search

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Use these links to find recent scientific publications via CAB Abstracts (log in required unless accessing from a subscribing organisation).


Porcine circovirus structure and replication: a minireview. Weingartl, H. M.; University of Maribor, Faculty of Agriculture, Maribor, Slovenia, Agricultura (Slovenia), 2002, 1, 1, pp 11-14, 28 ref. - Full Test article