A commercial vaccine based on PCV2a and an experimental vaccine based on a variant mPCV2b are both effective in protecting pigs against challenge with a 2013 U.S. variant mPCV2b strain

Tanja Opriessnig, Priscilla Freitas Gerber, Chao-Ting Xiao, Mark Mogler, Patrick G Halbur

Research output: Contribution to journalArticlepeer-review

Abstract

During 2012 and 2013, an apparent increase in porcine circovirus associated disease occurred in the USA. A variant PCV2b strain designated mPCV2b was recovered from many of these cases. This raised concerns of a decrease in efficacy of commercially available PCV2 vaccines. The objective of this study was to compare the ability of a commercial PCV2a-based vaccine and an experimental mPCV2b-based vaccine to control mPCV2b-associated disease, lesions, and viremia in a challenge model. Twenty-six caesarian-derived, colostrum-deprived pigs were randomly assigned to one of four groups: (1) vaccinated with a commercial PCV2a-based vaccine and challenged (PCV2a-VAC; n=7), (2) vaccinated with an experimental mPCV2b-based vaccine and challenged (mPCV2b; n=7), (3) sham-vaccinated with saline and challenged (positive controls; n=7), and (4) sham-vaccinated with saline without challenge (negative controls; n=5). Vaccination was done on D0 and D14, challenge was done on D28 using a tissue homogenate containing PRRSV and mPCV2b and the experiment was terminated on D49. Among the challenged pigs, 47.6% (10/21) developed severe clinical disease and either died or had to be humanely euthanized between D39 and D48 (11-20 days after challenge). PCV2 viremia was almost completely absent in the vaccinated groups regardless of vaccine type except for two PCV2a-vaccinated pigs which had detectable PCV2 DNA levels on individual days after challenge. Microscopic lesions typical of PCV2 infection were limited to the positive control group which developed mild-to-severe lesions associated with low-to-abundant PCV2 antigen. Under the conditions of this study, PCV2 vaccines regardless of PCV2 type were effective against mPCV2b challenge.
Original languageEnglish
Pages (from-to)230–237
Number of pages8
JournalVaccine
Volume32
Issue number2
Early online date19 Nov 2013
DOIs
Publication statusPublished - 3 Jan 2014

Keywords

  • Experimental model
  • PCV2a
  • Porcine circovirus type 2 (PCV2)
  • Vaccination
  • Vaccine
  • mPCV2b

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