DNA was extracted from 200 µL of serum or 300 µL of OF samples, by using the MagMAX™ Pathogen RNA/DNA Kit (Applied Biosystems) following the manufacturer’s instructions. The DNA obtained was suspended in 90 µL of elution solution.
To quantify the PCV2 DNA in serum and OF samples, a real-time qPCR assay (LSI VetMAX™ Porcine Circovirus Type 2 Quantification, Life Technologies) was performed. Each extraction and qPCR plate included negative controls (diethylpyrocarbonate (DEPC)-treated water) and each sample reaction had an internal positive control (IPC) to monitor DNA extraction and amplification procedures. Viral concentrations were expressed as the mean log10 PCV2 genome copies/mL. Area under the curve (AUC) of viral load in serum samples from 2 to 25 weeks of age was calculated according to the trapezoidal method as previously described [23 (link)].
To quantify the PCV2 DNA in serum and OF samples, a real-time qPCR assay (LSI VetMAX™ Porcine Circovirus Type 2 Quantification, Life Technologies) was performed. Each extraction and qPCR plate included negative controls (diethylpyrocarbonate (DEPC)-treated water) and each sample reaction had an internal positive control (IPC) to monitor DNA extraction and amplification procedures. Viral concentrations were expressed as the mean log10 PCV2 genome copies/mL. Area under the curve (AUC) of viral load in serum samples from 2 to 25 weeks of age was calculated according to the trapezoidal method as previously described [23 (link)].