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Introduction: Enzootic pneumonia still causes major economic losses to the intensive pig production. Vaccination against its primary pathogen, Mycoplasma hyopneumoniae , is carried out worldwide to control the disease and minimize clinical signs and performance losses. Nonetheless, the effects of both infection with, and vaccination against Mycoplasma hyopneumoniae on the innate and adaptive immune responses remain largely unknown. Therefore, we conducted a study in which piglets were injected once with a commercial bacterin V1 or V2, or the adjuvant of V1 (A) to investigate their effect on local, innate and adaptive immune responses., Methods: Three weeks after vaccination, piglets were challenge infected with M. hyopneumoniae and euthanized four weeks later to assess vaccine efficacy via macroscopic and microscopic evaluation of lung lesions. Blood and broncho-alveolar lavage fluid (BAL) samples were collected to measure antibody responses, cellular immunity, BAL cytokine levels and BAL M. hyopneumoniae DNA load as well as cytokine secretion by monocytes., Results: After vaccination, proliferation of antigen-specific CD3 + T cells and a higher percentage of TNF-α + CD8 + , and TNF-α + and TNF-α + IFN-γ + CD4 + CD8 + T cells was seen in V1, while proliferation of or a significant increase in cytokine production by different T cell subsets could not be observed for animals from V2. Interestingly, LPS-stimulated blood monocytes from V1 and A secreted less IL-10 on D7. After challenge, higher levels of IgA, more IL-10 and less IL-1β was detected in BAL from V1, which was not observed in V2. Animals from A had significantly more IL-17A in BAL. The macroscopic lung lesion score and the M. hyopneumoniae DNA load at euthanasia was lower in V1, but the microscopic lung lesion score was lower in both vaccinated groups., Discussion: In conclusion, these results indicate that the two commercial bacterins induced different local and adaptive immune responses, that the adjuvant alone can reduce anti-inflammatory innate immune responses, and that both vaccines had a different efficacy to reduce Mycoplasma -like lung lesions and M. hyopneumoniae DNA load in the lung., Competing Interests: Author RK was employed by CEVA Santé Animale, Libourne, France. The study was partially funded by CEVA Santé Animale, Libourne, France. CEVA Santé Animale participated in the study design, and in the review of the final manuscript., (Copyright © 2022 Beuckelaere, Haspeslagh, Biebaut, Boyen, Haesebrouck, Krejci, Meyer, Gleerup, De Spiegelaere, Devriendt and Maes.)

Background: A cross-sectional study was carried out to assess the prevalence of Mycoplasma hyopneumoniae infections before vaccination in 3-week-old piglets and to gain information about infection dynamics., Methods: In 13 German and three Austrian farms with a known history of enzootic pneumonia, 790 piglets and 158 sows were sampled (blood samples, tracheobronchial swabs [TBS] [piglets], laryngeal swabs [LS] [sows]), and 525 pen-based oral fluids (OFs) were collected in growing and fattening pigs. Laboratory diagnostics included enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR) analyses., Results: Antibodies to M. hyopneumoniae were present in 87.5 per cent of all herds. Seroprevalence ranged from 0.0 to 100.0 per cent and 0.0 to 88.0 per cent in sows and piglets, respectively. M. hyopneumoniae-deoxyribonucleic acid (DNA) was present in 3.8 and 0.4 per cent of LS and TBS, respectively. Gilts had a 10.9 times higher chance being M. hyopneumoniae PCR-positive than older sows. In 75.0 per cent of all farms, M. hyopneumoniae-DNA was present in OFs. Detection rate was significantly higher in OFs of 20-week-old than in younger pigs (p < 0.001)., Conclusion: Results indicate that M. hyopneumoniae infections of the lower respiratory tract in piglets are rare but highlight the role of gilts in maintaining infection in the herd. Collecting OFs seems promising for surveillance, if coughing occurs simultaneously., (© 2022 The Authors. Veterinary Record published by John Wiley & Sons Ltd on behalf of British Veterinary Association.)

This study aimed to describe Mycoplasma hyopneumoniae (M. hyopneumoniae) genetic variability in vaccinated (V) and non-vaccinated (NV) slaughtered pigs showing cranio-ventral pulmonary consolidation (CVPC). Ten V and 10 NV fattening farms with respiratory problems associated to M. hyopneumoniae were selected. Lung lesions of one batch per farm were scored at slaughterhouse and the enzootic pneumonia (EP)-index was calculated. Moreover, three lungs showing the most extensive CVPC per farm were sampled and tested for M. hyopneumoniae detection by real-time (rt)-PCR. Positive samples with cycle threshold ≤30 were selected to be genotyped by sequencing of four loci (P97, P146, H1 and H5). Typing profiles (TP) were assigned considering four or two (P97, P146) loci. Five commercial vaccines for M. hyopneumoniae (VS) and two reference strains (RF) were also genotyped. The EP-index (mean ± SD) in NV farms (3.8 ± 1.9) was not significantly different from V ones (2.2 ± 1.3). From the 60 selected lungs, 46 (76.7%) were M. hyopneumoniae positive by rt-PCR (25/30 and 21/30 from NV and V farms, respectively), and 43 (93.5%) of those were successfully genotyped. A total of 24 different TP(12 in V and 12 in NV farms) or 17 TP(9 in V and 9 in NV farms, being one TP in both farm types) were identified by analyzing four or two loci, respectively. One to three TP per farm were detected, being different from VS and RF. Interestingly, farms with same breeding origin had the same TP using two loci, but such link was not found using four loci. Therefore, high inter-farm and limited intra-farm M. hyopneumoniae genetic variability were detected, but variability depended on the number of studied loci., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This study evaluated different gilt vaccination protocols against Mycoplasma (M.) hyopneumoniae at acclimation and their effect on the genetic diversity. A total of 180 M. hyopneumoniae naïve gilts were selected 1 week post-entry (wpe) at the acclimation barn in a clinically affected M. hyopneumoniae farm. Gilts were distributed according to the M. hyopneumoniae antibodies levels into three different vaccination schedules: A) four doses of a M. hyopneumoniae commercial vaccine at 2, 4, 6 and 8 wpe; B) two vaccine doses at 2 and 6 wpe and PBS at 4 and 8 wpe; and C) four PBS doses at the same wpe. Detection of M. hyopneumoniae (rt-PCR) and antibodies (ELISA) were assessed in gilts at 1, 14, 27 and 34 wpe and in 6 of their piglets at weaning. Rt-PCR positive gilts were detected at 14 wpe, being the proportion significantly lower in groups A and B (3/120, 3%) than C (27/60, 45%). Seroconversion was detected at 14 wpe, showing significant differences in percentage of inhibition (PI) between groups A (median 4.9, range 3.1-19.9) and B (5.5, 3.7-13.5), and C (14.3, 3.3-53.2). Gilts remained seropositive over the study and significant differences in PI were detected between groups A and B versus C. All piglets were rt-PCR negative, but the proportion of seropositive piglets coming from vaccinated gilts was significantly higher than the non-vaccinated group. M. hyopneumoniae characterization showed high variability. Hence, gilt vaccination with 2 or 4 doses significantly decreased the pathogen infectious pressure, variability, and provided high antibody levels to gilts and their offspring., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Mycoplasma hyopneumoniae (M. hyopneumoniae) is the primary agent of enzootic pneumonia in pigs. Pigs are often infected with different M. hyopneumoniae strains. This study assessed the efficacy of vaccination against experimental infection with two genetically different M. hyopneumoniae strains in weaned piglets. At 33 days of age (D0), 45 M. hyopneumoniae-free piglets were randomly assigned to three different groups: 1) negative control group (NCG; n = 5): not vaccinated, not infected, 2) positive control group (PCG; n = 20): not vaccinated, infected, and 3) vaccination group (VG; n = 20): single vaccination with an inactivated whole-cell M. hyopneumoniae vaccine (Hyogen®, Ceva) (D1), infected. The PCG and VG were endotracheally inoculated with 7 × 10 7 CCU in 7 ml of the highly virulent M. hyopneumoniae strain F7.2C (D24) and 7 × 10 7 CCU in 7 ml low virulent strain F1.12A (D25). A respiratory disease score (RDS) was assessed from D24 until D53. At D53 (euthanasia), macroscopic lung lesions (MLL) were scored, log copies of M. hyopneumoniae DNA (qPCR) and IL-1 and IL-6-concentrations (ELISA) on bronchoalveolar lavage fluid were determined., Results: The RDS and MLL at euthanasia were respectively 0, 1.20 and 0.55 (P < 0.001) and 0, 7.56 and 0.68 (P < 0.001) for NCG, PCG and VG, respectively. The qPCR results for PCG and VG were 3.99 and 1.78 log copies (P < 0.001), respectively, with a significant difference between PCG and VG. The IL-1 and IL-6 results at euthanasia for NCG, PCG and VG were 17.61, 1283.39 and 53.04 pg/ml (P < 0.001) and 148.10, 493.35 and 259.80 pg/ml (P = 0.004), respectively with a significant difference between PCG and VG., Conclusions: Vaccination with Hyogen® in pigs was efficacious against an experimental challenge with both a low and highly virulent M. hyopneumoniae strain as the vaccinated pigs coughed significantly less, and showed significantly less lung lesions compared to the non-vaccinated challenged pigs: the vaccinated animals showed a 52.9% lower RDS and 91.0% lower MLL compared to the PCG. In the bronchoalveolar lavage fluid collected at the necropsy of the vaccinated pigs, a significantly lower amount of M. hyopneumoniae-DNA and a significantly lower IL-1 and IL-6 concentration was found compared to the pigs of the PCG.