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Background A field efficacy trial was conducted on three farms to evaluate a novel combined vaccine containing porcine circovirus types 2a/d (PCV2a/d), Mycoplasma hyopneumoniae, and M. hyorhinis. Methods Three farms with a history of subclinical PCV2 infection, enzootic pneumonia, and polyserositis were enrolled. Each farm included 40 piglets (18 days old), which were randomly allocated to vaccinated or unvaccinated groups. Pigs in the vaccinated group received a single 2‐mL intramuscular dose of the combined vaccine at 21 days of age, while unvaccinated pigs received phosphate‐buffered saline. Results Vaccination significantly improved (p < 0.05) body weight and average daily weight gain on all three farms compared with unvaccinated pigs. Vaccinated pigs mounted protective humoral and cellular immune responses against PCV2, M. hyopneumoniae, and M. hyorhinis. Furthermore, vaccination reduced viral and mycoplasmal loads in serum, laryngeal, and nasal samples and decreased the severity of associated lesions. Conclusions The combined vaccine demonstrated strong efficacy under field conditions, providing protection against subclinical PCV2 infection, enzootic pneumonia caused by M. hyopneumoniae, and polyserositis caused by M. hyorhinis. These findings support its potential as an effective intervention for improving both health and productivity in swine herds. A field trial on three commercial farms evaluated a combined vaccine targeting PCV2a/d, Mycoplasma hyopneumoniae, and Mycoplasma hyorhinis. Vaccinated pigs showed improved average daily weight gain, stronger immune responses against these pathogens, and significantly reduced viral and mycoplasmal loads and lesion severity, supporting its efficacy under field infection conditions.

This paper aims to update the molecular status of porcine circovirus 2 (PCV2) in Malaysia. Firstly, the molecular detection rate of PCV2 in farm and sampled pig population were reported to be 83.78% (31/37 farms) and 83.54% (66/79 pigs) positive for PCV2, respectively. PCV2 was detected across all age groups, from fetuses, porkers to sows. Co-detection of PCV2 and PCV3 antigens was also reported at a rate of 28.77% (21/73). Secondly, PCV2 antigen was also detected in Malaysian abattoir lung samples: 18 out of 19 (94.74%) samples originating from clinically healthy finishers were tested positive. Further, this is the first study to confirm the circulation of PCV2 in the wild boar population roaming Peninsular Malaysia, where 28 out of 28 (100%) wild boar lung samples were found positive. One decade earlier, only genotype PCV2b was reported in Malaysia. This most recent update revealed that genotypes PCV2a, PCV2b and PCV2d were present, with PCV2d being the predominant circulating genotype. PCV2 cap gene nucleotide sequences in this study were found to be under negative selection pressure, with an estimated substitution rate of 1.102 × 10−3 substitutions/site/year (ssy).

Background: The efficacy of a novel combined vaccine targeting porcine circovirus types 2a/d (PCV2a/d), Mycoplasma hyopneumoniae, and M. hyorhinis was evaluated in a controlled challenge study. Methods: A total of 45 pigs were randomly allocated into nine groups (five pigs per group). Vaccinated groups received a single 2 mL intramuscular dose of the combined vaccine and were subsequently challenged with PCV2a, PCV2d, M. hyopneumoniae, and M. hyorhinis. Unvaccinated groups received a single 2 mL intramuscular dose of phosphate-buffered saline (0.01 M, pH 7.4). Growth performance, systemic adaptive immune (humoral and cellular) responses, viremia, laryngeal and nasal mycoplasma loads, and histopathological lesions were assessed. Results: Vaccinated pigs exhibited enhanced growth performance and elicited systemic immune responses, including both humoral and cellular immunity, against all four pathogens. Vaccination also significantly reduced viremia, mycoplasmal loads in laryngeal and nasal swabs, and the severity of associated lesions compared with unvaccinated controls. Conclusions: These results indicated that the combined vaccine was efficacious and conferred protection against PCV2a, PCV2d, M. hyopneumoniae, and M. hyorhinis challenge under experimental conditions. This combined vaccine represented an effective strategy to enhance growth performance and control complex co-infection in swine populations.

In the context of the carboxyl-terminus (C-terminus) of the capsid protein of porcine circovirus type 2a (PCV2a) and PCV2a vaccines, this study aimed to explore its unrevealing cryptic epitope and its relation to PCV2-infected herd immunity. To discover the C-terminus of the capsid protein of PCV2a, monoclonal antibodies (mAbs) were generated in this work. Two mAbs bound the two minimal linear epitopes (229PPLKP233 and 228DPPLNP233 (or 229PPLNP233)), which were located at the C-terminus of the capsid proteins of PCV2a and PCV2b, respectively. One mAb bound to the minimal linear epitope (220QFREFNLK227, peptide P82), but it neither bound the virus-like particle (VLP) of PCV2a nor produced positive staining in PCV2a-infected cells by immunofluorescence assay. Further, the residues 220–227 were not accessible on the surface of the VLP on the three-dimensional model, but the residues 228–231 extend toward the VLP exterior. Immunoassays were conducted in this study to screen anti-viral peptide-specific IgGs, which could differentiate vaccinated pigs from non-vaccinated ones. The data show two 220QFREFNLKDPPLKP233-containing peptides had a significantly higher binding reactivity with sera from PCV2-infected pigs in the control group than with sera from the VLP-vaccine group, particularly seen in sera from swine aged 15 weeks to 24 weeks. However, the peptide P82 had not this phenomenon in that test. This study confirmed that C-terminal epitopes play an important role in PCV2-induced decoy of swine humoral immunity.

The objective of this study was to compare two different bivalent vaccines containing porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae . One vaccine contained PCV2a and the other contained PCV2b, and both were administered on a farm suffering from subclinical PCV2d infection and enzootic pneumonia. A total of 180 pigs were randomly divided into 3 groups (60 pigs per group; male pigs = 30 and female pigs = 30). Bivalent vaccination significantly improved growth performance in both vaccinated groups as compared to the unvaccinated (UnVac) group. Growth performance measured by body weight and average daily weight gain (ADWG) was not significantly different between the two bivalent-vaccinated groups (VacA and VacB). Both bivalent vaccines elicited high levels of neutralizing antibodies and interferon-γ secreting cells (IFN-γ-SC) against PCV2d, leading to a reduction in the levels of PCV2d blood viral load as compared to unvaccinated animals. Similarly, both bivalent vaccines elicited high levels of IFN-γ-SC against M. hyopneumoniae that reduced the level of M. hyopneumoniae laryngeal viral loads as compared to unvaccinated animals. Significant differences in severity of lung and lymphoid lesions were observed in both vaccinated groups as compared to the UnVac group. These comparative field data demonstrated that both bivalent vaccines are good candidates for controlling subclinical PCV2d infection and enzootic pneumonia in swine farms suffering from an existing infection.

In order to diagnose a respiratory disease in a pig farm, the lungs, spleen, and lymph nodes of three dead pigs were collected for pathogen detection by PCR and isolation on the basis of preliminary clinical diagnosis. The virus isolate was identified by gene sequence analysis and Immunoperoxidase monolayer assay (IPMA). The bacterial isolate was identified by biochemical tests, 16S rDNA sequence analysis, and species- and serotype-specific PCR, and the pathogenicity was analyzed. Porcine circovirus type 2a (PCV2a) genotype from the lungs, spleen, and lymph nodes and Pasteurella (P.) multocida capsular serotypes D from the lungs were found. The PCV2a isolates could specifically bound the anti-PCV2-Cap polyclonal antibody. The 16S rDNA sequence of P. multocida isolates had 99.9% identity with that of the strain from cattle, and the isolate was highly pathogenic to mice. The results showed that the co-infection of PCV2a and P. Multocida capsular serotypes D should be responsible for the disease. The uncommon PCV2a is still prevalent in some pig farms besides the dominant PCV2d genotype. This study could provide important etiological information for effective control and treatment of the disease in pig farms.