Porcine Circoviruses: Difference between revisions

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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)

Caused by a porcine circovirus alone or in combination with porcine parvovirus
May cause mild interstitial pneumonia, failure of lungs to collpse on opening the thoracic cavity
Microscopically: thickening of alveolar wall due to type 2 pneumocyte hyperplasia

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-{{OpenPagesTop}}
+{{unfinished}}
-Also known as: '''''Post-weaning Multisystemic Wasting Syndrome — PMWS — Porcine Dermatitis and Nephropathy Syndrome — PDNS — PCV '''''
-== Introduction ==
+====Antigenicity====
-There are two serotypes of porcine circovirus, which are as follows; PCV1 which is harmless and PCV2 which is virulent. The virulent serotype, PCV2, causes Post-weaning Multisystemic Wasting Syndrome (PMWS) in young pigs and Porcine Dermatitis and Nephropathy Syndrome (PDNS) in older pigs.
+*Two serotypes:
-<br>
+**PCV1 is harmless
-PCV2 is the most important widespread porcine virus as it causes detrimental losses to the industry and predisposes to secondary infection, which obviously can result in further losses. It is easily misdiagnosed. Route of transmission is via the faeco-oral route or venereal route. The host often mounts a poor immune response to the virus.
+**PCV2 is virulent, causing:
+***Post-weaning Multisystemic Wasting Syndrome (PMWS) in young pigs
+***Porcine Dermatitis and Nephropathy Syndrome (PDNS) in older pigs
-== PMWS ==
+====Pathogenesis====
-This disease causes enlarged lymph nodes and [[lymphopenia]], as the virus concentrates in germinal centers.
+'''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 [[Classical Swine Fever|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
-=== Signalment ===
+====Epidemiology====
-Typically strikes '''weaners''' of around 8-12 weeks old.
+*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
-=== Clinical Signs ===
+====Diagnosis====
-Clinical signs include pale skin colour and/or jaundiced skin, enlarged lymph nodes and kidneys, and unthrifty appearance and lameness. There may also be signs of respiratory disease, such as mild [[Interstitial Pneumonia|interstitial pneumonia]], failure of lungs to collapse on opening the thoracic cavity and also diarrhoea. Some may present as sudden death and mortality rates can reach 40% in an outbreak.
+*Clinical signs
+*Confirmed by PCR for PCV2 nucleic acid
+*However, positives can show NO clinical signs
+*Easily confused with [[Classical Swine Fever]]
-=== Differential Diagnoses ===
+====Control====
-There are a large range of differentials, particularly [[Classical Swine Fever]], [[African Swine Fever]], ''Pasteurella'', and colisepticemia.
+*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
-== PDNS ==
+===Postweaning multisystemic wasting syndrome (PMWS)===
-This condition can follow PMWS or can be seen as a stand alone condition and presents as an immune-mediated '''necrotising vasculitis'''.
-=== Signalment ===
+*Caused by a [[Circoviridae|porcine circovirus]] alone or in combination with [[Parvoviridae|porcine parvovirus]]
-It is typically seen in growers and finishers.
+*May cause mild [[Lungs Inflammatory - Pathology#Interstitial pneumonia|interstitial pneumonia]], failure of lungs to collpse on opening the thoracic cavity
+*Microscopically: thickening of alveolar wall due to type 2 pneumocyte hyperplasia
-=== Clinical Signs ===
-Signs can include extensive hemorrhages of kidneys and skin, especially in the scrotal region, accompanied by pyrexia.
-== Diagnosis ==
-Diagnosis of these conditions is based on clinical signs and history and signalment. Definitive diagnosis can be achieved by performing a PCR for the PCv nucleic acid, however some positive animals can show no clinical signs. Differentials such as Classical Swine Fever must be ruled out.
-== Treatment and Control ==
-Vaccines are available for control of PMWS. [[Antibiotics]] can be used to treat/prevent any secondary bacterial infections.
-Control measures include good ventilation, bio-security and proper management. Passive antibody can sometimes be used in severe circumstances.
+[[Category:Circoviridae]][[Category:Pig]]
+[[Category:To_Do_-_Clinical/Viruses]]
-{{Learning
-|full text = [http://www.cabi.org/cabdirect/FullTextPDF/2008/20083075304.pdf ''' 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.]
-}}
-{{review}}
-{{OpenPages}}
-[[Category:Circoviridae]][[Category:Pig Viruses]]
-[[Category:Expert_Review - Farm Animal]]
 [[Category:Respiratory_Viral_Infections]]
-[[Category:Musculoskeletal Diseases - Pig]][[Category:Intestinal Diseases - Pig]][[Category:Respiratory Diseases - Pig]][[Category:Urological Diseases - Pig]]