A commercial PCV2a-based vaccine significantly reduces PCV2b transmission in experimental conditions.
Transmission characteristics of PCV2 have been compared between vaccinated and non-vaccinated pigs in experimental conditions. Twenty-four Specific Pathogen Free (SPF) piglets, vaccinated against PCV2 at 3weeks of age (PCV2a recombinant CAP protein-based vaccine), were inoculated at 15days post-vaccination with a PCV2b inoculum (6⋅10(5) TCID50), and put in contact with 24 vaccinated SPF piglets during 42days post-inoculation. Those piglets were shared in six replicates of a contact trial involving 4 inoculated piglets mingled with 4 susceptible SPF piglets. Two replicates of a similar contact trial were made with non-vaccinated pigs. Non vaccinated animals received a placebo at vaccination time and were inoculated the same way and at the same time as the vaccinated group. All the animals were monitored twice weekly using quantitative real-time PCR and ELISA for serology until 42days post-inoculation. The frequency of infection and the PCV2 genome load in sera of the vaccinated pigs were significantly reduced compared to the non-vaccinated animals. The duration of infectiousness was significantly different between vaccinated and non-vaccinated groups (16.6days [14.7;18.4] and 26.6days [22.9;30.4] respectively). The transmission rate was also considerably decreased in vaccinated pigs (β=0.09 [0.05-0.14] compared to β=0.19 [0.11-0.32] in non-vaccinated pigs). This led to an estimated reproduction ratio of 1.5 [95% CI 0.8 - 2.2] in vaccinated animals versus 5.1 [95% CI 2.5 - 8.2] in non-vaccinated pigs when merging data of this experiment with previous trials carried out in same conditions.
Anses, Laboratoire de Ploufragan-Plouzané, BP 53, 22440 Ploufragan, France; Université Bretagne Loire, Rennes, France. Electronic address: nicolas.rose@anses.fr.
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Rose
Anses, Laboratoire de Ploufragan-Plouzané, BP 53, 22440 Ploufragan, France; Université Bretagne Loire, Rennes, France.
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Andraud
Anses, Laboratoire de Ploufragan-Plouzané, BP 53, 22440 Ploufragan, France; Université Bretagne Loire, Rennes, France.
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L
Bigault
Anses, Laboratoire de Ploufragan-Plouzané, BP 53, 22440 Ploufragan, France; Université Bretagne Loire, Rennes, France.
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A
Jestin
Anses, Laboratoire de Ploufragan-Plouzané, BP 53, 22440 Ploufragan, France; Université Bretagne Loire, Rennes, France.
B
B
Grasland
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018173:Circoviridae Infections / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary*; D017925:Circovirus; D056724:Immunity, Humoral; D013047:Specific Pathogen-Free Organisms; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control* / Q000635:transmission / Q000821:virology; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D014765:Viral Vaccines
Porcine Circovirus type 2; Reproduction number; Transmission; Vaccination