Naturally co-infected boars with both porcine reproductive and respiratory syndrome virus and porcine circovirus type 2.

In this study, the humoral response against porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2), the presence of the virus in semen and serum and the genetic characteristics of the virus detected in 15 boars from a commercial farm were analysed. The results showed that 53% of the boars presented anti-PRRSV antibodies and 100% presented anti-PCV2 antibodies. Porcine reproductive and respiratory syndrome virus was detected in 43% of the boars and 73% were positive to PCV2. The complete ORF5 gene of PRRSV of 14 samples and a fragment of the ORF2 gene of PCV2 of 22 samples were sequenced. Porcine reproductive and respiratory syndrome virus analysis revealed <92% identity in viruses from semen and serum of two boars, whereas in the rest of the boars the identity was >97.5%. As for PCV2, two boars presented an identity <95% in serum and semen and the rest had an identity >96%. The results showed that PRRSV- and PCV2-naturally infected boars can be found, and at least two different strains of viruses from semen and serum can be detected.