PCV2

Porcine circovirus type 2 (PCV2) is a small, non-enveloped DNA virus in the Circoviridae family that infects domestic pigs and wild boar. The genome is a circular single-stranded DNA molecule about 1.7 kilobases in length, with two major open reading frames encoding replication proteins (ORF1) and the capsid protein (ORF2).

PCV2 is widespread and often present at subclinical levels; disease association occurs when infection coincides with immune stress or co-infections, leading to PCV-associated diseases (PCVAD), including PMWS, PDNS, and respiratory and enteric disturbances. Genotypes such as PCV2a, PCV2b, PCV2c, and PCV2d have been described.

Transmission occurs mainly via the fecal-oral route and direct contact; vertical transmission and environmental contamination contribute. Subclinical infections are common; disease outbreaks are influenced by management, genetics, and co-infections. PCV2 is maintained in pig populations worldwide.

Diagnosis relies on a combination of clinical signs, histopathology showing lymphoid depletion and granulomatous inflammation, and demonstration of PCV2 DNA or antigen in affected tissues by PCR and immunohistochemistry. Serology indicates exposure but does not confirm disease.

Prevention and control focus on vaccination against PCV2, which reduces clinical disease and mortality, improved biosecurity, and management practices to reduce stress and co-infections. There is no specific antiviral treatment; supportive care is used for affected pigs. PCV2 is not considered a zoonotic threat.