Comparative Evaluation of Growth Performance between Bivalent and Trivalent Vaccines Containing Porcine Circovirus Type 2 (PCV2) and Mycoplasma hyopneumoniae in a Herd with Subclinical PCV2d Infection and Enzootic Pneumonia

A Chimeric Vaccine against Porcine Circovirus Type 2: Meta-Analysis of Comparative Clinical Trials

This meta-analysis compared the efficacy of a chimeric vaccine against porcine circovirus type 2 (PCV2) containing the genotypes PCV2a+b (Fostera® Gold PCV MH [FOS-G]), with commonly used vaccines being derived from genotype PCV2a, considering the following parameters: average daily gain (ADG), mortality and market classification as full value and cull. Data from seven hitherto unpublished comparative US field trials with FOS-G (two experimental challenges and five natural environmental studies) were provided by the manufacturer. A complementary literature review revealed a Korean study, which was considered separately in meta-analysis. Competitors were Circumvent® PCV-M (CV) and Ingelvac Circoflex® + Ingelvac Mycoflex® (IC + IM) in the US, and Porcilis® (POR) in Republic of Korea. Heterogeneity between experimental and environmental challenge studies in the US was not significant, justifying a combined analysis. Over the entire feeding period, ADG (11 comparisons), mortality (12 comparisons) and market classification were not significantly different between FOS-G and its competitor in the US setting. In the Korean study, however, ADG was higher in pigs vaccinated with FOS-G compared to POR, whereas mortality was not significantly different.

Evaluation of porcine circovirus type 2 double vaccination in weaning piglets that reared for gilts under field conditions

The objective of the present study was to evaluate the efficacy of a porcine circovirus type 2 (PCV2) double vaccination in weaning piglets reared for gilts under field conditions. The study was conducted at a Greek farrow-to-finish conventional pig farm with a previous history of PCV2 infections. The trial included 96 female piglets at 21 days of age, which were equally allocated to two different study groups. Piglets of the group-1 received a single PCV2 vaccination at 21 days of age, while piglets of the group-2 were double vaccinated against PCV2, at 21 and 42 days of age. The results indicated that the piglets of group-2 had better growth performance, as they showed higher body weight (BW) and average daily weight gain (ADWG). In addition, ELISA tests showed that the double- vaccinated piglets presented a better humoral response against PCV2, as higher levels of IgG antibodies were detected in them than the piglets of the group-1. In conclusion, the current results suggested that a double PCV2 vaccination of piglets, reared for gilts, on a PCV2-affected farm could lead to higher protection against the virus.

Non-Inferiority Field Study Comparing the Administrations by Conventional Needle-Syringe and Needle-Free Injectors of a Trivalent Vaccine Containing Porcine Circovirus Types 2a/2b and Mycoplasma hyopneumoniae

The objective of this study was to assess the clinical, immunological, microbiological, and pathological evaluation of trivalent vaccine containing porcine circovirus types 2a/b (PCV2a/b) and Mycoplasma hyopneumoniae given by two different needle-free injection devices compared with conventional needle-syringe injection in a herd with subclinical PCV2d infection and enzootic pneumonia. A total of 240 21-day-old pigs, which weighed between 5 to 6 kg, were randomly divided into four groups (60 pigs per group, 30 = male and 30 = female per group). Injection site reactions in the pigs were minimal for the two needle-free injection devices and needle-syringe injection. Trivalent vaccination of pigs with two needle-free injection devices was not inferior to conventional needle-syringe injection for growth performance. Trivalent vaccination of pigs with two different needle-free injection devices reduced levels of PCV2d loads in serum and M. hyopneumoniae loads in the larynx equally compared to the conventional needle-syringe injection. The amount of PCV2d load in serum from the needle-free Pulse FX injection device at 49 days post vaccination showed non-inferiority to conventional needle-syringe injection. The immune response against PCV2 and M. hyopneumoniae to trivalent vaccine given with the needle-free Pulse FX injection device was non-inferior to conventional needle-syringe injection. The pigs from the two needle-free injection device and conventional needle-syringe injection had significantly (p < 0.05) lower macroscopic and microscopic lung lesion scores, and microscopic lymphoid lesions than from unvaccinated. The results of this study demonstrated that vaccination of trivalent vaccine by the two needle-free Pulse injection devices used in the study was non-inferior to that by conventional needle-syringe injection for growth performance, immune response against PCV2 and M. hyopneumoniae, and reduction of PCV2 viremia.

Efficacy of bivalent vaccines of porcine circovirus type 2 and Mycoplasma hyopneumoniae in specific pathogen-free pigs challenged with porcine circovirus type 2d

Background

Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (MHP) are economically significant pathogens in the pig industry. The use of combined vaccines against PCV2 and MHP is one of the most effective ways of protecting pigs from both diseases, and it has become a part of general management.

Objectives

This study evaluated the efficacy of two new bivalent vaccines of PCV2 and MHP (Myco-X and Myco-XD) in SPF pigs. Myco-X and Myco-XD are a combined vaccine of MHP with PCV2b and PCV2d, respectively.

Methods

Sixteen pigs were divided into four groups: Myco-X-vaccinated challenged, Myco-XD-vaccinated challenged, unvaccinated challenged, and unvaccinated unchallenged. Two milliliters of Myco-X were administered intramuscularly, and 0.5 mL of Myco-XD was injected intradermally at 3 wk of age. The pigs were challenged with virulent PCV2d via the intramuscular and intranasal route 4 wk post-vaccination.

Results

All vaccinated pigs showed effective reduction of the clinical signs, the PCV2d load in the blood and nasal swab samples, as well as lung and lymphoid tissue lesions in the challenge test. Compared to unvaccinated challenged animals, the vaccinated challenged animals showed significantly higher (p < 0.05) levels of anti-PCV2 IgG, PCV2d-specific interferon-γ (IFN-γ), and anti-MHP IgG.

Conclusions

Based on clinical, microbiological, serological, and pathological assessments, this study confirmed that both combined vaccines could protect pigs against PCV2 infection caused by PCV2d. On the other hand, further research on the efficacy evaluation of these new vaccines against the MHP challenge and PCV2d/MHP co-challenge is needed.