Effect of porcine circovirus type 2 (PCV2) vaccination on PCV2-viremic piglets after experimental PCV2 challenge

Abstract

The objective of this study was to evaluate the effect of porcine circovirus type 2 (PCV2) vaccines on PCV2-viremic and -seropositive piglets born from naturally PCV2-infected sows against postnatal PCV2 challenge. The experimental design was aimed at mimicking commercial swine rearing conditions to evaluate the response of the PCV2 vaccine on PCV2-viremic and -seropositive piglets after experimental PCV2 challenge. PCV2a (or 2b)-viremic piglets received a PCV2 vaccine at 21 days of age followed by a PCV2b (or 2a) challenge at 49 days of age (28 days post vaccination). The PCV2 vaccines elicited a high level of humoral (as measured by immunoperoxidase monolayer assay and neutralizing antibody titers) and cellular (as measured by the frequency of PCV2-specific interferon-γ-secreting cells) immune response in the PCV2-viremic piglets after vaccination even in the presence of maternally derived antibodies (MDA). The initial infection of PCV2 in the pigs was not affected by PCV2 vaccination, however the challenging PCV2 was reduced by PCV2 vaccination on PCV2-viremic pigs. The results from this study demonstrate that the PCV2 vaccine used in this study is effective at reducing PCV2 viremia and lymphoid PCV2 DNA, even for PCV2-viremic pigs with passively acquired MDA at the time of vaccination.

Evaluation of natural porcine circovirus type 2 (PCV2) subclinical infection and seroconversion dynamics in piglets vaccinated at different ages

“…In the present farm scenario, vaccination at 10 weeks of age was able to numerically reduce the percentage of viremic animals at 14 (peak of infection), 18 and 25 weeks of age in comparison with the control group, being statistically significant at the latter time point. This evidence is in agreement with a previous experimental trial [33], showing that vaccination of PCV2 viremic and seropositive piglets leads to a humoral and cellular immune response able to reduce PCV2 viremia. Therefore, although not optimal, vaccination of viremic pigs seems to exert a positive effect compared to viremic, non-vaccinated ones.…”

Porcine circovirus type 2 associated reproductive failure in a specific pathogen free (SPF) piglet producing herd in Norway: a case report

“…Vaccines against PCV2 infection are quite effective [ 24 , 25 ] and vaccines marketed for sows exist (Circovac®, Merial, Lyon, France; Ingelvac CircoFLEX®, Boehringer Ingelheim Vetmedica GmbH, Ingelheim/ Rhein, Germany). The elected timepoint of dam vaccination can influence the antibody levels in piglets [ 26 ].…”

A commercial PCV2a-based vaccine significantly reduces PCV2b transmission in experimental conditions

“…From 2006, commercial vaccine solutions were made available on the market. Based on different principles (inactivated PCV2, PCV2 capsid protein produced in a vector or chimeric inactivated PCV1 virus including PCV2 ORF2), the efficacy of those vaccines, prepared with strains of PCV2a genogroup, has been described in several experimental [5] or field studies [6][7][8][9][10][11]. Generally, commercial vaccines have been shown to reduce viraemia, viral load in tissues and lymphoid lesions [12][13][14].…”