Studies on Porcine Circovirus Type 2 Vaccination of 5-Day-Old Piglets

Abstract

Porcine circovirus type 2 (PCV2) vaccines have become widely used since they became available in 2006. It is not uncommon for producers to use PCV2 vaccines in pigs younger than what is approved by manufacturers. The objective of this study was to determine the efficacy of a chimeric and a subunit PCV2 vaccine administered at 5 or 21 days of age. Forty-eight PCV2-naïve piglets were randomly divided into six groups of eight pigs each. Vaccination was done at day 5 or day 21, followed by triple challenge with PCV2, porcine parvovirus (PPV), and porcine reproductive and respiratory syndrome virus (PRRSV) at day 49. Vaccinated pigs seroconverted to PCV2 approximately 14 days postvaccination and had a detectable neutralizing antibody response by 21 days postvaccination regardless of age at vaccination. At day 49, the pigs vaccinated with the chimeric vaccine had significantly higher levels of neutralizing antibodies than the pigs vaccinated with the subunit vaccine. After challenge, vaccinated pigs had significantly decreased levels of PCV2 viremia and a decreased prevalence and severity of microscopic lesions compared to the positive-control group, which had severe lymphoid lesions associated with abundant PCV2 antigen, compatible with PCV-associated disease. The results of this study indicate that, under the conditions of this study, vaccination of PCV2-naïve pigs at day 5 or day 21 resulted in development of a detectable humoral immune response and provided reduction or complete protection against PCV2 viremia and PCV2-associated lesions after triple challenge with PCV2, PPV, and PRRSV.

Characterization of a Novel Porcine Parvovirus Tentatively Designated PPV5

“…To evaluate potential cross-reactivity between PPV1, PPV4 and PPV5 capsid proteins the following samples from nursery pigs with known PPV1 status, determined by a hemagglutination inhibition (HI) assay [29], were utilized: 18 experimental samples with 6/18 negative control samples, 3/18 samples from pigs with low levels of passively derived antibodies, and 9/18 positive control samples collected 21 days post experimental infection with PPV1 as described [30], [31]. In addition to samples from experimentally infected pigs, 22 field samples from breeding sows with known positive HI status from two different farms were tested.…”

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

“…Under no vaccinated sow scenario, little information is available whether the 3–4 week vaccination-age offers the best profit. Although PCV2 vaccines are routinely used in most of the worldwide porcine production systems, peer-reviewed studies comparing the efficacy of PCV2 vaccination at different ages are scarce in experimental [10, 11] and, particularly, under field conditions [12]. …”

Immune Responses of Piglets Immunized by a Recombinant Plasmid Containing Porcine Circovirus Type 2 and Porcine Interleukin-18 Genes

“…Immunization against PCV2 has been studied intensely and found to be the most effective strategy for protecting pigs to date (11,13,21). However, the current vaccines do have some disadvantages.…”

“…The subunit vaccines are the PCV2 capsidbased subunit vaccines expressed in a Baculovirus vector with high cost. Currently, the commercially inactivated whole virus versus subunit vaccines cause low antibody levels, and the duration of immunity available ranges from 4 to 6 months (12,21,30). Multi-immunization is therefore required to achieve a lasting and efficient immunity response, which increases the cost for farms (9,26).…”