PCV2 vaccine cross-protection: Identification of sequences in successfully vaccinated field cases

摘要

Primary control for porcine circovirus type 2 (PCV2) is vaccination of pigs around the age of weaning with PC V2 vaccines which are efficacious at controlling the disease when administered to the pigs according to label. Vaccination does not eliminatePCV2 exposure in the barns; therefore, PCV2 can still be found in successfully vaccinated hetds even with optimal protection. In 2012, it was reported that a novel mutation of PCV2 could be a possible cause of disease in pigs but vaccination non-compliance could not be ruled out.1 Since then, current commercial PCV2 vaccines have been shown to be efficacious against this described novel strain.2,3 Schwartz reported that there had been a shift from PCV2b to PCV2d (new designation for the PCV2 mutation reported by Opriessnig in 2013) in the industty, at least from clinical cases submitted to the Iowa State University Veterinary Diagnostic Labotatory.4 It is necessary to evaluate emerging isolates in control cases (PCV2 exposed pigs, vaccinated with PCV2vaccines with no PCVAD signs and with satisfied owners and veterinarians on control) as well as clinical cases in order to determine the importance of novel mutations in the industry. The primary objective of this study was to identify PCV2 isolates exposing herds where nursery and finisher production performance was meeting the systems' expectations, no clinical PCVAD signs were apparent and both the ownership and veterinary staff were satisfied with their use of Ingelvac CircoFLEX~R at weaning age.