PCVAD – Porcine Circovirus Associated Diseases


Other issues related to PCV2


Causal agent

Porcine Circovirus II – and conditions where the virus may be found in high numbers. Extremely small DNA virus (genome in a circle) none enveloped.

Name extremely confusing as PCVII is present in almost all pigs and therefore if isolated can be “associated” with any condition.

Age group

Foetus - death abortion and myocarditis

Weaner – PCVAD, PMWS

Grower – PCVAD, PMWS, PDNS, Granulomatous enteritis, Necrotic pneumonitis

Adults – abortion and no symptoms


Clinical signs


Abortion, infertility, mummification and stillborn piglets


If the pigs are severely stressed with primary pathogens or management problems.  Parvovirus and PRRSv can play significant roles in the induction of a PCVII problem.  However, the problem will generally present as a single batch or a series of batches but only while the management/diseases problems persist.

PMWS - 15-60 kg pigs present with acute wasting – generally within 4 days becoming extremely emaciated.  Surrounding pigs are normal and then waste rapidly.  Mortality generally extremely high – 20% or more. Death is associated with other infections already on the farm.


May present with part of the weaner PMWS issues on the farm.

Growers may present with PDNS, however, role of PCVII in PDNS is not determined.  Another virus Torque Teno virus may be associated.

Granulomatous enteritis may be associated with PCVII and results in ileitis and wasting disorders.  However, not all cases of Granulomatous enteritis are associated with PCVII.

Necrotic pnuemonitis has been also associated with PCVII, however in about 15% cases PCV2 is not found.


Abortion is described.  However, reproductive effects are minimal/non-existent.  Could play a role in SMEDI syndromes on farms.

Normal pig

Most pigs and almost all pig farms are infected with PCVII completely asymptomatically.

Mummified piglets kim

PCVii au eco 6 9 weeks old

PMWS kr 9b wasting

Foetus myocarditis

PCVAD – PCVII+feeding issues

PMWS in a 20 kg weaner

pdns kr1

Abortion au 54 days

Nursery ecoshelter 8



Normal pigs with PCVII




PCVII is extremely resistant virus.



PCVII can be found in semen

PCVII occurs normally on all farms

Post-mortem Lesions – not PMWS or PDNS see separate pages

Normal pig


Weaner - PCVII

Pigs with enhanced wasting in excess of normal expectations

Single or generally enlargement of lymph nodes.

Liver may be pale.  With associated starvation the pig may have a gastric ulcer.  Lungs may present with an histiocytic interstitial pneumonia.  There may be enlarged kidneys with white spots visible on the surface.

Histological lesions include: lymphoid depletion, granulomatous inflammation with syncytial formation.  Histiocytic infiltration.  Presence of botryoid basophilic intra-cytoplasmic inclusion bodies which stain for PCVII by immunohistochemistry. Note these lesions are identical to those associated with PMWS. There will be no increase in PDNS cases.

PCVii b1 inguinal lymphnodes 1

PCVii au a14 jaundice liver

PCVII d22 kidney spots

Prominent lymph nodes

Pale liver

Enlarged, kidneys with white spots

PCVII c7 lung pneumonic

PCVII e15 gastric lymphnode

Salmonella 3au 3e

Histiocytic Interstitial pneumonia

Gastrohepatic lymph node enlarged

Other lesions depending on primary cause – Salmonella colitis

Penumonia PCV2 au weaner 3pm1

PCVII lymphnode

PCVII iowa 2

Severe pneumonia – Pasteurella as a primary problem

Lymphoid depletion in the lymph node

Immunohistochemistry for PCVII

PCVAD histological scores



Granulomatous enteritis.  This might be confused with PIA/ileitis and may be considered to be a differential diagnosis.

Colitis kim 3

Granulomatous enteritis IHC PCVII

Granulomatous enteritis

Granulomatous enteritis with associated PCVII IHC


Foetal myocarditis with associated PCVII


PCVII may act as a SMEDI virus in the pregnant sow resulting in death of the piglets – the stage of pregnancy results in a variety of clinical signs – infertility, embryonic death, mummification and stillborn piglets.  Spread between foetuses is extremely limited

PCVII foetal mycocarditis 1  PCVII foetal mycocarditis 2

Myocarditis of foetal heart with ICH for PCVII



Immunohistochemistry and characteristic histology changes

Reading IHC slides

Note need at least 5 lymph nodes to be considered a generalised problem

General investigation

Antibodies and virus isolation generally unrewarding as virus ubiquitous.  There is no correlation with presence of antibody or virus in pigs.  This is a waste of clients money to investigate using these techniques.

Antibody concentration of marginal benefit.

PCR unrewarding on blood as all pigs positive

Move piglets to a separate ideal environment – with PMWS the weaners will still die, with PCVAD mortality problems will cease.

With management changes post-weaning mortality will fall below 1.66xsd of normal herd mortality over period of 2 months


Normal pig

Ensure feedback programmes are adequate to ensure stable herd immunity

Ensure good pig flow management to achieve all-in/all-out


(not PMWS)

Resolve management and pathogen overload problem

Post-weaning feeding regimes

Pig flow and internal biosecurity

Resolve PRRSv and SIV problems and associated biosecurity issues

Vaccination may be considered, but extremely expensive and management issues will need to be addressed eventually anyway

Vaccinate pigs before 5 weeks of age.   Vaccination of PCV2


Vaccinate using PCVII pre-farrow to the sow or piglets in farrowing house or at weaning


See PMWS advice sheets

Common differentials


PMWS, Ileitis other causes of pneumonia and wasting.  Other causes of abortion. Note a transient lymph node enlargement is normal in healthy young pigs –PCV2?

Other issues

There are now a variety of other viruses which are being associated with PCVAD conditions – Torque Teno virus and Toro viruses for example.  Their true association (if any) will become apparent with time.

Zoonotic implications


None specifically.  May increase prevalence of meningitis and salmonella which are zoonotic.