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Background: Mycoplasma hyopneumoniae is the etiological agent of mycoplasmal pneumonia of swine (MPS). Commercial vaccines provide partial protection and do not prevent the colonization and transmission of M. hyopneumoniae. The bottleneck in the development of more effective vaccines for MPS is the stimulation of effective immune responses in the host. The purpose of the present study was to evaluate the immune responses of immunodominant proteins Mhp170, Mhp274 and Mhp336 in BALB/c mice. Methods: The recombinant Mhp170 (rMhp170), Mhp274 (rMhp274), and Mhp336 (rMhp336) proteins were purified from recombinant bacteria. Fifty-two six-week-old SPF female BALB/c mice were divided into five groups: a commercial inactivated vaccine-immunized group, three recombinant protein-inoculated groups, and a PBS-treated group. The physical parameters and body weights of the mice were observed during the experiment. The lung/body coefficient and macroscopic and microscopic lung lesions were evaluated. IgG and its isotypes IgG1 and IgG2a in serum and BALF and sIgA in BALF were assessed. The levels of IFN-γ, IL-4, and IL-17, in the supernatants of splenocytes and in serum were measured, and the mRNA levels of three cytokines in splenocytes were analyzed. Finally, lymphocyte proliferation after stimulation with corresponding proteins or crude extract of M. hyopneumoniae J strain was assessed. Results: We successfully constructed recombinant bacteria expressing rMhp170, rMhp274, and rMhp336. None of the mice from all groups presented adverse reactions and macroscopic and microscopic lung lesions. rMhp170 and rMhp274 were capable of inducing the production of IgG, IgG1 and IgG2 in serum and BALF, the secretion of IFN-γ, IL-4 and IL-17 in serum, the expression of IFN-γ, IL-4 and IL-17 mRNAs in splenocytes, and high levels of lymphocyte proliferation. Moreover, rMhp274 significantly increased sIgA in BALF. Nevertheless, rMhp336 induced only IgG, IgG1 and IgG2 production in sera; the secretion of IFN-γ and IL-4 in sera and BALF; the expression of IFN-γ and IL-4 mRNAs in the splenocyte population; and lymphocyte proliferation. Conclusion: Mhp170 and Mhp274 induced Th1/Th2/Th17 immune responses, and Mhp336 stimulated mixed Th1/Th2-type immune responses, in mice. Our data suggest that Mhp274 is a potential viable candidate for the development of a subunit vaccine for MPS. [ABSTRACT FROM AUTHOR]

Simple Summary: This study represents the first comprehensive investigation of pig lung microbiome in Thailand. We employed 16S rRNA sequencing to characterize the microbial communities in the pig lungs. In the study, pathogenic bacteria were identified in both normal and pneumonic lungs, indicating that nearly all pigs in the herd are at risk of developing respiratory diseases, with some potentially acting as asymptomatic carriers. To enhance production efficiency in subsequent batches, additional measures such as alternative vaccination programs, optimized medication strategies, and stringent biosecurity protocols should be implemented. Bacterial respiratory disease is one of the major concerns in the modern pig industry. To address the limitations of culture-based methods, 16S rRNA sequencing was employed to characterize the pig lung microbiome to gain a better understanding of microbial physiology and their population genetics. A batch of 510 slaughtered pigs from a farm located in Lampang province, Thailand, was selected. Individual pig weight was recorded. A total of 24 lungs (10 normal and 14 pneumonic lungs) were sampled for gross lesion examination and lung microbial communities were investigated. Poor growth performance and weight uniformity were denoted in this batch. Several pathogenic bacteria were detected in both normal and pneumonic lungs. Microbial diversity was decreased in the pneumonic group. PCoA and NMDS analysis showed a clear separation between the groups. Stenotrophomonas spp. (42.12%) was the dominant genus identified in normal lungs, while Mycoplasma hyopneumoniae (71.97%) was the most abundant in pneumonic lungs, correlating with the commonly observed consolidation lesions. The slaughterhouse serves as a key checkpoint for gathering comprehensive information on pig respiratory health, and lung is representative of the lower respiratory tract for microbiomics. Monitoring of lung lesions should be implemented routinely to gain a better understanding of regional pig respiratory health. [ABSTRACT FROM AUTHOR]

Background: Several epidemiological studies have been carried out using Multiple-Locus Variable-number tandem repeat Analysis (MLVA) for M. hyopneumoniae typing. However, a global perspective on the implications of the genetic diversity of this pathogen is lacking. Objective: This study aimed to determine and to analyze the genetic structure of M. hyopneumoniae based on the p97 R1- p146 R3 MLVA typing scheme and to characterize, analyze and compare MLVA types among countries where the information was publicly available. Methods: A set of 797 publicly available data of M. hyopneumoniae p97 R1- p146 R3 MLVA genetic types from six different countries were analyzed using Genalex 6.41 software to characterize loci polymorphism and using Structure 2.3.4 software in order to identify the genetic structure. Results: A total of 185 MLVA types were identified among the analyzed data. For the p97 R1 and p146 R3 loci, most of the molecular variation in M. hyopneumoniae populations was identified within countries. Three genetic clusters and their recombinations were identified globally. Conclusion: M. hyopneumoniae is a genetically diverse pathogen with limited clonality and three well-defined clusters and their combinations were identified in this investigation. The greatest genetic variation of M. hyopneumoniae was observed within countries. [ABSTRACT FROM AUTHOR]

Cranioventral pulmonary consolidation (CVPC) is a common lesion observed in the lungs of slaughtered pigs, often associated with Mycoplasma (M.) hyopneumoniae infection. There is a need to implement simple, fast, and valid CVPC scoring methods. Therefore, this study aimed to compare CVPC scores provided by a computer vision system (CVS; AI DIAGNOS) from lung images obtained at slaughter, with scores assigned by human evaluators. In addition, intra- and inter-evaluator variability were assessed and compared to intra-CVS variability. A total of 1050 dorsal view images of swine lungs were analyzed. Total lung lesion score, lesion score per lung lobe, and percentage of affected lung area were employed as outcomes for the evaluation. The CVS showed moderate accuracy (62–71%) in discriminating between non-lesioned and lesioned lung lobes in all but the diaphragmatic lobes. A low multiclass classification accuracy at the lung lobe level (24–36%) was observed. A moderate to high inter-evaluator variability was noticed depending on the lung lobe, as shown by the intraclass correlation coefficient (ICC: 0.29–0.6). The intra-evaluator variability was low and similar among the different outcomes and lung lobes, although the observed ICC slightly differed among evaluators. In contrast, the CVS scoring was identical per lobe per image. The results of this study suggest that the CVS AI DIAGNOS could be used as an alternative to the manual scoring of CVPC during slaughter inspections due to its accuracy in binary classification and its perfect consistency in the scoring. [ABSTRACT FROM AUTHOR]

Despite the large wild boar population in South Korea, research on infectious diseases is limited. We investigated the prevalence of infectious diseases caused by Porcine Circovirus Type 2 (PCV2), Aujeszky’s Disease Virus (ADV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Mycoplasma hyopneumoniae in 400 wild boars in South Korea. PCV2 antibodies were detected in 223 samples, antigens in 112, and both in 101. ADV and PRRSV antibodies were detected in one and three samples, respectively. M. hyopneumoniae antibodies were identified in 28 samples. PCV2 was detected in all nine regions, M. hyopneumoniae in five, PRRSV in three, and ADV in one. Infectious-disease monitoring is crucial to safeguard wild boars. [ABSTRACT FROM AUTHOR]

This study evaluated the minimum inhibitory concentration (MIC) of pradofloxacin against various swine respiratory pathogens, including Bordetella bronchiseptica, Glaesserella parasuis, Mycoplasma hyopneumoniae, Pasteurella multocida, and Streptococcus suis (S. suis), associated with disease in swine. This research was conducted in two phases: the initial phase examined isolates from the lungs that could be either commensal or pathogenic, while the second phase focused on systemic S. suis strains that spread from the respiratory tract to the brain. The pradofloxacin MIC values of the second phase were within the MIC range of the initial phase, with MIC50 and MIC90 values highlighting its potential as an effective antimicrobial agent. Quality control data validated the reliability of our MIC findings, with all pradofloxacin MIC values for control organisms within approved ranges. These findings suggest that pradofloxacin has broad-spectrum activity against Gram-positive and Gram-negative bacteria and may serve as a reliable therapeutic option for managing S. suis and other swine respiratory infections. This study highlights pradofloxacin as an alternative antimicrobial therapy for swine respiratory diseases, offering a potential solution amidst rising concerns over antibiotic resistance. [ABSTRACT FROM AUTHOR]

Mycoplasma hyopneumoniae (M. hyopneumoniae) is one of the primary agents involved in porcine respiratory disease complex, and circulates in the swine industry worldwide. The prevention and control of M. hyopneumoniae is complicated. Thus, a recombinase-aided amplification (RAA) assay coupled with the clustered regularly-interspaced short palindromic repeats (CRISPR)/Cas12a system was established for the detection of M. hyopneumoniae. The most suitable primer pairs and CRISPR RNA (crRNA) were screened and selected for the RAA-CRISPR/Cas12a detection system. We have achieved a detection limit of 1 copy/µL and 5 copies/µL per reaction for the RAA-CRISPR/Cas12a-fluorescence assay and RAA-CRISPR/Cas12a-lateral flow assay (LFA), respectively. Furthermore, the RAA-CRISPR/Cas12a system displayed no cross-reactivity with other respiratory pathogens. The performance of the RAA-CRISPR/Cas12a system was compared with PCR as recommended by the Chinese national standard (GB/T 35909-2018) and qPCR as recommended by the Chinese entry–exit inspection and quarantine industry standard (SN/T4104-2015) for clinical samples, and good consistency with these methods was observed. Above all, the methods shed a light on the convenient, portable, visual, highly sensitive and specific detection of M. hyopneumoniae , demonstrating a great application potential for on-site monitoring of M. hyopneumoniae in the field. [ABSTRACT FROM AUTHOR]

Abstract Cranioventral pulmonary consolidation (CVPC) is a common lesion observed in the lungs of slaughtered pigs, often associated with Mycoplasma (M.) hyopneumoniae infection. There is a need to implement simple, fast, and valid CVPC scoring methods. Therefore, this study aimed to compare CVPC scores provided by a computer vision system (CVS; AI DIAGNOS) from lung images obtained at slaughter, with scores assigned by human evaluators. In addition, intra- and inter-evaluator variability were assessed and compared to intra-CVS variability. A total of 1050 dorsal view images of swine lungs were analyzed. Total lung lesion score, lesion score per lung lobe, and percentage of affected lung area were employed as outcomes for the evaluation. The CVS showed moderate accuracy (62–71%) in discriminating between non-lesioned and lesioned lung lobes in all but the diaphragmatic lobes. A low multiclass classification accuracy at the lung lobe level (24–36%) was observed. A moderate to high inter-evaluator variability was noticed depending on the lung lobe, as shown by the intraclass correlation coefficient (ICC: 0.29–0.6). The intra-evaluator variability was low and similar among the different outcomes and lung lobes, although the observed ICC slightly differed among evaluators. In contrast, the CVS scoring was identical per lobe per image. The results of this study suggest that the CVS AI DIAGNOS could be used as an alternative to the manual scoring of CVPC during slaughter inspections due to its accuracy in binary classification and its perfect consistency in the scoring.

Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae are causative agents of the porcine respiratory disease complex. However, information on the prevalence of these pathogens in wild boars is scarce. This study aimed to investigate the presence of antibodies to Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae in wild boars in Serbia. In this study 253 serum samples from wild boars were tested for anti-bodies to Mycoplasma hyopneumoniae and Actinobacillus pleuropneumonia using the ELISA assay. The overall seroprevalence rates of Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae were 4.2% and 56.9%, respectively. Antibodies to both pathogens were detected in 20 sera samples (7.9%). The prevalence of wild boars that were seropositive for Mycoplasma hyopneumoniae differed with age and ranged from 10.7% to 33.3%, and for Actinobacillus pleuropneumoniae, it ranged from 51.8% to 83.3%. Wild boars are hard to control and are considered a high-risk infection source for outdoor and backyard pigs and eventually for commercial indoor farms as well. Thus, the result of this first serosurvey in Serbia should raise awareness of the importance of wild boars as potential reservoirs of bacterial pathogens such as Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. Our data revealed the circulation of both pathogens in wild boars in Serbia, drawing attention to the potential health risk they present for domestic swine health. [ABSTRACT FROM AUTHOR]

Simple Summary: This study evaluated the health and economic impacts of respiratory diseases, specifically pleurisy and pneumonia, in finishing pigs. These conditions are common in intensive pig farming and lead to reduced growth rates, lower carcass quality, and significant economic losses. In this research, pigs from a farm with a history of respiratory diseases were monitored through their finishing phase, with lung and pleura samples collected at slaughter. The results showed a high prevalence of lung lesions, notably bronchopneumonia, with frequent co-infections by pathogens such as Mycoplasma (M.) hyopneumoniae and Actinobacillus (A.) pleuropneumoniae. The severity of pleurisy lesions correlated with lower average daily gain (ADG) and higher production costs. Economic analysis indicated that pigs with severe pleurisy yielded lower profits due to reduced carcass weight and increased costs, emphasizing the need for effective disease management. This study highlights the significant toll that respiratory diseases take on pig production, both in animal health and profitability, underscoring the importance of preventive measures to improve welfare and economic outcomes. Respiratory diseases, such as pleurisy and pneumonia, cause significant health and economic losses in pig production. This study evaluated 867 finishing pigs from a farm with a history of respiratory issues, using macroscopic lesion scoring (SPES and CVPC), histopathological analysis, qPCR diagnostics, and economic modeling. Severe pleurisy (scores 3 and 4) was observed in 42.1% of carcasses and was strongly correlated with higher bacterial loads of Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, and Pasteurella multocida. Severe lesions reduced the average daily gain (ADG) and carcass weight, leading to increased production costs and lower profitability. Economic analysis revealed that pigs with higher pleurisy scores incurred an additional cost per kg (USD 1.29 vs. USD 1.32 for milder cases), reduced total revenue by 1.36%, and decreased return on investment (ROI) from 5.33% to 3.90%. These findings emphasize the critical impact of respiratory diseases on profitability and the necessity of robust health management strategies, including vaccination and enhanced biosecurity, to minimize economic losses in swine farming. [ABSTRACT FROM AUTHOR]

Mycoplasma hyopneumoniae, an important cause of enzootic pneumonia in pigs in many countries, has recently been shown to exhibit reduced susceptibility to several antimicrobial classes. In the present study, a total of 185 pig lung tissue samples were collected from abattoirs in Australia, from which 21 isolates of M. hyopneumoniae were obtained. The antimicrobial resistance profile of the isolates was determined for 12 antimicrobials using minimum inhibitory concentration (MIC) testing, and a subset (n = 14) underwent whole-genome sequence analysis. MIC testing revealed uniformly low values for enrofloxacin (≤1 μg/mL), florfenicol (≤8 μg/mL), lincomycin (≤4 μg/mL), spectinomycin (≤4 μg/mL), tetracycline (≤0.5 μg/mL), tiamulin (≤2 μg/mL), tildipirosin (≤4 μg/mL), tilmicosin (≤16 μg/mL) tulathromycin (≤2 μg/mL), and tylosin (≤2 μg/mL). Higher MICs were observed for erythromycin (MIC range: 16–32 μg/mL), gamithromycin, and tilmicosin (MIC range of both: 32–64 μg/mL). Whole-genome sequencing of the isolates and additional screening using mismatch amplification mutation assay PCR did not identify any known genetic resistance markers within 23S rRNA (macrolides), DNA gyrase A, and topoisomerase IV genes (fluoroquinolones). The WGS data also indicated that the Australian M. hyopneumoniae isolates exhibited limited genetic diversity and formed a distinct monophylectic clade when compared to isolates from other countries. These findings indicate that Australian M. hyopneumoniae likely remains susceptible to the major antimicrobials used to treat enzootic pneumonia in pigs and have evolved in isolation from strains identified in other pig-producing countries. [ABSTRACT FROM AUTHOR]

[Background/Objectives] Mycoplasma hyopneumoniae (M. hyopneumoniae) is widespread in the global swine industry, leading to significant economic losses, and is particularly severe in native Chinese pig breeds. The Ningxiang pig, a well-known native breed in China, is susceptible to M. hyopneumoniae, exhibiting high morbidity and mortality rates. This study was designed to evaluate the clinical effectiveness of the M. hyopneumoniae live vaccine (strain 168). [Methods] The vaccine was delivered to 7-day-old piglets in the farrowing room through intrapulmonary administration, and its efficacy was compared with that of the M. hyopneumoniae inactivated vaccine (strain J). Four experimental groups were designed: Group 1 (inactivated vaccine + inactivated vaccine), Group 2 (live vaccine + inactivated vaccine), Group 3 (live vaccine), and Group 4 (control), which was not vaccinated. The production performance of each group was measured, and the lung lesion scores and pneumonia lesion reduction rates were evaluated at slaughter. Nasal swabs and serum samples were collected on days 0, 14, 28, 56, 84, 112, and 140 to assess SIgA, IgG antibody levels, and the M. hyopneumoniae pathogen. [Results] The results showed that Group 3 had the best production performance and clinical outcomes, with the lowest average lung lesion score, of 4.43 ± 2.44, which was significantly different from the other groups (*** p < 0.001). [Conclusions] This study provided scientific evidence to support vaccination strategies for preventing and controlling the M. hyopneumoniae in native pig populations. [ABSTRACT FROM AUTHOR]

Mycoplasma pneumonia (MPS), caused by Mycoplasma hyopneumoniae (Mhp), is a chronic, airborne respiratory disease that poses a significant threat to the global swine industry. The P97 and P46 proteins are major antigens of Mhp, with the R1 region of P97 possessing full adhesive capability. Studies have shown that the main antigenic regions of Mhp P42 and P65 proteins exhibit strong immunogenicity. In this study, we first linked the genes encoding P97R1 and P46 proteins to form the P97R1P65 gene and subsequently constructed three shuttle plasmids: pFBD-P97R1P46, pFBD-P97R1P46-p65, and pFBD-P65-P42. These proteins were expressed using the Bac to Bac system and formulated into subunit vaccines for mouse immunization. Mouse experiments indicated that the P97R1P46 + P65-P42 protein combination elicited higher levels of specific antibodies, IL-2, IL-4, and CD8+ T cells compared to other subunit vaccine groups, a finding further validated in subsequent mouse challenge protection experiments. Therefore, we utilized the MultiBac expression system to co-express P97R1P46, P65, and P42 proteins in the pFastMultibacDual vector for immunization experiments in piglets. The piglet immunization experiments demonstrated that the Mhp subunit vaccine prepared in this study could induce specific antibodies against Mhp, with the combination of P97R1P46, P65, and P42 proteins inducing the highest level of humoral immunity. This study provides valuable insights for the development of Mhp subunit vaccines. [ABSTRACT FROM AUTHOR]

Simple Summary: Antimicrobial resistance (AMR) in bacteria is a critical issue threatening both human and animal health. This paper focuses on Mycoplasma hyopneumoniae, a bacterium causing lung disease in pigs, leading to significant economic losses in the swine industry worldwide. The problem is that this bacterium has developed resistance to many antibiotics, making treatment difficult. The study aims to understand the genetic basis of AMR by analyzing the reported genome of Mycoplasma hyopneumoniae strains using advanced techniques like whole genome sequencing. Key findings indicate that genetic mutations in certain genes are responsible for this resistance. This review paper suggests a multidisciplinary approach combining genetic, phenotypic, and bioinformatics data is essential in combating ever-increasing AMR in Mycoplasma hyopneumoniae. These insights could lead to better treatment strategies, ultimately benefiting the swine industry by improving animal health and reducing economic losses. Understanding and managing AMR in Mycoplasma hyopneumoniae is crucial for developing more effective antimicrobial agents and securing sustainable food production, which has a direct impact on society by ensuring food security and animal welfare. Antimicrobial resistance (AMR) in Mycoplasma hyopneumoniae, the causative agent of Enzootic Pneumonia in swine, poses a significant challenge to the swine industry. This review focuses on the genetic foundations of AMR in M. hyopneumoniae, highlighting the complexity of resistance mechanisms, including mutations, horizontal gene transfer, and adaptive evolutionary processes. Techniques such as Whole Genome Sequencing (WGS) and multiple-locus variable number tandem repeats analysis (MLVA) have provided insights into the genetic diversity and resistance mechanisms of M. hyopneumoniae. The study underscores the role of selective pressures from antimicrobial use in driving genomic variations that enhance resistance. Additionally, bioinformatic tools utilizing machine learning algorithms, such as CARD and PATRIC, can predict resistance traits, with PATRIC predicting 7 to 12 AMR genes and CARD predicting 0 to 3 AMR genes in 24 whole genome sequences available on NCBI. The review advocates for a multidisciplinary approach integrating genomic, phenotypic, and bioinformatics data to combat AMR effectively. It also elaborates on the need for refining genotyping methods, enhancing resistance prediction accuracy, and developing standardized antimicrobial susceptibility testing procedures specific to M. hyopneumoniae as a fastidious microorganism. By leveraging contemporary genomic technologies and bioinformatics resources, the scientific community can better manage AMR in M. hyopneumoniae, ultimately safeguarding animal health and agricultural productivity. This comprehensive understanding of AMR mechanisms will be beneficial in the adaptation of more effective treatment and management strategies for Enzootic Pneumonia in swine. [ABSTRACT FROM AUTHOR]

Background/Objectives: Vaccination is a strategy in pig farming for the control of several pathogens, but commercial vaccines may have detrimental side effects. This study aimed to evaluate the effects of commercial vaccines on the control of porcine circovirus type 2 (PCV2), Mycoplasma hyopneumoniae (Mhp), and Lawsonia intracellularis (L. intracellularis) and their potential side effects on welfare, behavior, acute inflammation biomarkers (C-reactive protein and haptoglobin), and the performance of piglets during the nursery phase. Methods: A total of 240 piglets, both female and castrated males, with an average weight of 6.3 ± 0.9 kg were subjected to four treatments: T1-FLEXcombo® (Ingelvac®CircoFLEX and Ingelvac®MycoFLEX) + Enterisol® Ileitis; T2-FLEXCombo® + Porcilis® Ileitis; T3-Porcilis® PCV M HYO + Porcilis® Ileitis; and T4-FLEXCombo® + 0.9% saline solution. This study measured therapeutic interventions, body condition score, behavioral changes, rectal temperature, and inflammation biomarkers post-vaccination. Results: The T3 group required more therapeutic interventions and exhibited a 23.1% higher incidence of thin body condition (p < 0.05) and 10 times more animals with depressed behavior than T1 (p < 0.05). The piglets vaccinated for L. intracellularis (T2 and T3) had rectal temperatures exceeding 39.7 °C post-vaccination, significantly higher than in T1 (p < 0.05). The T1 animals showed five times more positive behavior traits 24 h after vaccination (p < 0.05). Touch response was 29% lower in the T2 and T3 groups, and the lying down behavior was higher in these groups compared to T1. Additionally, 41.7% of the T3 animals exhibited a sitting posture 48 h after vaccination. Higher serum C-reactive protein and haptoglobin levels were observed in T3 (p < 0.05) at 24 and 48 h post-vaccination. Feed intake was higher in T1 compared to T3 between 29 and 35 days of age. It is important to note that this study did not measure immune responses to the pathogens and did not include challenge tests, and therefore, it does not assess which vaccine is superior in pathogen control. Conclusions: The vaccine programs resulted in similar zootechnical performance. However, T1, T2, and T4 showed better effects on piglet welfare and behavior compared to T3. [ABSTRACT FROM AUTHOR]

Porcine Respiratory Disease Complex (PRDC) presents a complex etiopathology that poses challenges for veterinarians. Typically, a primary microorganism acts as the initiating factor, allowing secondary pathogens to exacerbate respiratory complications. Notable initiating viruses include Swine Influenza Virus (SIV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Porcine Circovirus Type 2 (PCV2). Mycoplasma hyopneumoniae (Mhp) and Actinobacillus pleuropneumoniae (App) are frequently cited as initiating bacteria. The profound influence of environmental conditions on animal health underscores the necessity for tailored environmental adjustments. Optimal husbandry practices, including improved living conditions, reduced stocking density, and mitigation of stressors, are pivotal at all production stages. Technological innovations for health monitoring should also be considered. Effective immunoprophylaxis for PRDC is constrained due to its multifactorial nature. However, substantial reductions in associated losses can be achieved through vaccinations targeting PRRSV, Mhp, and App, followed by SIV. Vaccination against PCV2, Bordetella bronchiseptica, and Pasteurella multocida is also justified. Treatment of PRDC necessitates a comprehensive approach encompassing pathogen elimination, supportive therapy, and mitigation of detrimental influences on animal health and immunity. Additionally, specialized respiratory support supplements for farm animals are commercially available. [ABSTRACT FROM AUTHOR]

Random treatment assignment is essential in demonstrating a causal relationship between a treatment and the outcome of interest. Randomisation ensures that animals assigned to different treatment groups do not differ from each other systematically, except for the randomly assigned treatment. The randomisation pattern should also dictate the statistical analysis. [ABSTRACT FROM AUTHOR]

Mycoplasma (M.) hyopneumoniae is the key pathogen of the porcine respiratory disease complex (PRDC) and contributes to pleurisy in pigs. Due to its limited metabolism and laborious cultivation, molecular tools are useful for diagnosis. This study investigated the genetic diversity of M. hyopneumoniae in slaughter pigs with pneumonia and pleurisy, and it assessed co-infections by Pasteurella multocida type A (PM), Actinobacillus pleuropneumoniae (APP), and swine influenza virus A (sIVA). Lungs (n = 70) with different pleurisy scores and lesions compatible with M. hyopneumoniae infection were collected for convenience. Macroscopic and microscopic evaluations were performed. M. hyopneumoniae was detected using qPCR, and MLST was used for genetic characterization. Co-infections with PM and APP were also evaluated by qPCR, while the immunohistochemistry assessed sIVA infection. All lungs were positive for M. hyopneumoniae. Histopathology confirmed M. hyopneumoniae-associated lesions. MLST characterization was possible in 25 lungs and revealed 10 distinct allelic profiles, with none matching known sequence types in the public database. Co-infections were detected in 40% of the samples with APP and 32% with PM, with 12% showing both pathogens and 52% of the samples presenting microscopic lesions compatible with sIVA infection. The diverse genetic profiles found underscore the need for research on isolation and potential pathogenic variations. [ABSTRACT FROM AUTHOR]

BackgroundMycoplasma hyopneumoniae is the etiological agent of mycoplasmal pneumonia of swine (MPS). Commercial vaccines provide partial protection and do not prevent the colonization and transmission of M. hyopneumoniae. The bottleneck in the development of more effective vaccines for MPS is the stimulation of effective immune responses in the host. The purpose of the present study was to evaluate the immune responses of immunodominant proteins Mhp170, Mhp274 and Mhp336 in BALB/c mice.MethodsThe recombinant Mhp170 (rMhp170), Mhp274 (rMhp274), and Mhp336 (rMhp336) proteins were purified from recombinant bacteria. Fifty-two six-week-old SPF female BALB/c mice were divided into five groups: a commercial inactivated vaccine-immunized group, three recombinant protein-inoculated groups, and a PBS-treated group. The physical parameters and body weights of the mice were observed during the experiment. The lung/body coefficient and macroscopic and microscopic lung lesions were evaluated. IgG and its isotypes IgG1 and IgG2a in serum and BALF and sIgA in BALF were assessed. The levels of IFN-γ, IL-4, and IL-17, in the supernatants of splenocytes and in serum were measured, and the mRNA levels of three cytokines in splenocytes were analyzed. Finally, lymphocyte proliferation after stimulation with corresponding proteins or crude extract of M. hyopneumoniae J strain was assessed.ResultsWe successfully constructed recombinant bacteria expressing rMhp170, rMhp274, and rMhp336. None of the mice from all groups presented adverse reactions and macroscopic and microscopic lung lesions. rMhp170 and rMhp274 were capable of inducing the production of IgG, IgG1 and IgG2 in serum and BALF, the secretion of IFN-γ, IL-4 and IL-17 in serum, the expression of IFN-γ, IL-4 and IL-17 mRNAs in splenocytes, and high levels of lymphocyte proliferation. Moreover, rMhp274 significantly increased sIgA in BALF. Nevertheless, rMhp336 induced only IgG, IgG1 and IgG2 production in sera; the secretion of IFN-γ and IL-4 in sera and BALF; the expression of IFN-γ and IL-4 mRNAs in the splenocyte population; and lymphocyte proliferation.ConclusionMhp170 and Mhp274 induced Th1/Th2/Th17 immune responses, and Mhp336 stimulated mixed Th1/Th2-type immune responses, in mice. Our data suggest that Mhp274 is a potential viable candidate for the development of a subunit vaccine for MPS.

BackgroundSeveral epidemiological studies have been carried out using Multiple-Locus Variable-number tandem repeat Analysis (MLVA) for M. hyopneumoniae typing. However, a global perspective on the implications of the genetic diversity of this pathogen is lacking.ObjectiveThis study aimed to determine and to analyze the genetic structure of M. hyopneumoniae based on the p97R1-p146R3 MLVA typing scheme and to characterize, analyze and compare MLVA types among countries where the information was publicly available.MethodsA set of 797 publicly available data of M. hyopneumoniaep97R1-p146R3 MLVA genetic types from six different countries were analyzed using Genalex 6.41 software to characterize loci polymorphism and using Structure 2.3.4 software in order to identify the genetic structure.ResultsA total of 185 MLVA types were identified among the analyzed data. For the p97R1 and p146R3 loci, most of the molecular variation in M. hyopneumoniae populations was identified within countries. Three genetic clusters and their recombinations were identified globally.ConclusionM. hyopneumoniae is a genetically diverse pathogen with limited clonality and three well-defined clusters and their combinations were identified in this investigation. The greatest genetic variation of M. hyopneumoniae was observed within countries.

The objective of the study was to identify risk factors for reintroduction of Actinobacillus pleuopneumoniae and Mycoplasma hyopneumoniae (enzootic pneumonia) onto pig farms in areas in Switzerland that were involved in an eradication programme from 1996 to 1999 and to assess the role of dealers in relation to these reinfections. The study was based on the comparison of pig farms that were reinfected in the year 2000 (cases) and pig farms that remained uninfected in the same area (controls). Additionally, data were collected from Swiss pig dealers and transport companies. Out of a total of 3983 farms, 107 farms were reinfected in the year 2000. The incidences were 0.1% for Actinobacillus pleuopneumoniae and 2.6% for Mycoplasma hyopneumoniae (enzootic pneumonia). Compared to reinfection rates prior to the eradication programme, this is a considerable reduction. Statistically significant risk factors for the reinfection were 'finishing farm', 'large mixed breeding-finishing farm', 'reinfected neighbour' and 'parking site for pig transport vehicles close to the farm'. Pig farmers that purchased pigs from only one supplier per batch had a lower risk of reintroducing infection (protective factor). As long as infected and uninfected regions co-exist in Switzerland, direct and indirect contact between farms, pig herds and slaughter sites via transport vehicles are a major pathway of disease spread. Risk management measures linked to these contacts are therefore of key importance. The survey of dealers indicated various areas for improvement such as strategic planning of pick-up routes or cleaning and disinfecting of trucks. [ABSTRACT FROM AUTHOR]

Background: This field efficacy study was designed to determine the efficacy of a new bivalent vaccine containing porcine circovirus type 2d (PCV2d) and Mycoplasma hyopneumoniae at three independent pig farms. Methods: Three pig farms were selected based on their history of subclinical PCV2 infection and enzootic pneumonia. Each farm housed a total of 40, 18‐day‐old pigs that were randomly allocated to 1 of 2 treatment groups. Pigs were administered a 2.0 mL dose of the bivalent vaccine intramuscularly at 21 days of age in accordance with the manufacturer's recommendations, whereas unvaccinated pigs were administered a single dose of phosphate‐buffered saline at the same age. Results: Clinically, the average daily weight gain of vaccinated groups was significantly higher (p < 0.05) than those of unvaccinated animals during the growing (70–112 days of age), finishing (112–175 days of age) and overall (3–175 days of age) stages of production. Vaccinated animals elicited neutralizing anti‐PCV2 antibodies and PCV2d‐specific interferon‐γ secreting cells (IFN‐γ‐SC), which reduced the amount of PCV2d genomic copies in blood and reduced lymphoid lesions severity when compared with unvaccinated animals. Similarly, vaccinated animals elicited M. hyopneumoniae‐specific IFN‐γ‐SC, which reduced the amount of M. hyopneumoniae in the larynx and reduced lung lesions severity. Conclusions: The result of the field trial demonstrated that the bivalent vaccine was efficacious in the protection of swine herds suffering from subclinical PCV2d infection and enzootic pneumonia. [ABSTRACT FROM AUTHOR]

The non-specific protective effects offered by the concept of "innate immune memory" might represent a promising strategy to tackle early-life threatening infections. Here we tested the potential of an in vitro selected β-glucan in inducing trained immunity using an in vivo porcine model. We assessed the leukocyte transcriptome using blood transcriptomic module (BTM), proinflammatory cytokines, and clinical scoring after a first "training" and a second "stimulation" phase. The possible induction of innate immune memory was tested during a "stimulation" by an LPS-adjuvanted Mycoplasma hyopneumoniae vaccine (Hyogen®) one day after weaning. Following the "training", no major group differences were found, with the exception of a plasma TNF that was only induced by Adj and Adj_BG treatment. After vaccination, all groups developed similar antibody responses. A significant induction of plasma TNF and IL-1β was found in groups that received Adj and Adj_BG. However, following vaccination, the expected early innate BTMs were only induced by the PBS group. In conclusion, the adjuvant alone, adjuvant-formulated β-glucan, or orally applied β-glucan were unable to enhance innate immune reactivity but rather appeared to promote innate immune tolerance. Such an immune status could have both positive and negative implications during this phase of the piglet's life. [ABSTRACT FROM AUTHOR]

Background: Mycoplasma (M.) hyopneumoniae is associated with respiratory disease in pigs and is the primary agent of enzootic pneumonia. Quantification of M. hyopneumoniae-related outcome parameters can be difficult, expensive, and time-consuming, in both research and field settings. In addition to well-established methods, technological tools are becoming available to monitor various aspects of relevant animal- and environment-related features, often in real-time. Therefore, this study aimed to assess whether certain parameters, such as animal movement and body temperature using microchips (IMT), correlate with established parameters and whether the currently used parameters can be rationalized. Results: The percentage of movement was significantly reduced by M. hyopneumoniae infection in pigs (p < 0.05), where the M. hyopneumoniae-infected group showed a lower percentage of movement (1.9%) when compared to the negative control group (6.9%). On the other hand, macroscopic (MLCL) and microscopic (MLL) lung lesions, respiratory disease score (RDS), M. hyopneumoniae-DNA load, and anti-M. hyopneumoniae antibody levels increased significantly in the M. hyopneumoniae-infected group 28 days post-inoculation (p < 0.05). Moderate (r > 0.30) to very strong correlations (> 0.80) were observed between the abovementioned parameters (p < 0.05), except for IMT. A significant and moderate correlation was reported between IMT and rectal temperature (r = 0.49; p < 0.05). Last, the average daily weight gain and the percentage of air in the lung were not affected by M. hyopneumoniae infection (p > 0.05). Conclusions: M. hyopneumoniae infection significantly reduced the movement of piglets and increased lung lesions, M. hyopneumoniae-DNA load, and anti-M. hyopneumoniae antibody levels; and, good correlations were observed between most parameters, indicating a direct relationship between them. Thus, we suggest that changes in movement might be a reliable indicator of M. hyopneumoniae infection in pigs, and that a selected group of parameters—specifically RDS, MLCL, MLL, M. hyopneumoniae-DNA load, anti-M. hyopneumoniae antibody levels, and movement—are optimal to assess M. hyopneumoniae infection under experimental conditions. [ABSTRACT FROM AUTHOR]

Epizootic events of pneumonia, presumably caused by Mycoplasma ovipneumoniae, in bighorn sheep (Ovis canadensis) have been observed in the western United States and Canada. Until recently, it was thought that populations of Mexican (O. c. mexicana) and Nelson's (O. c. nelsoni) desert bighorn sheep in Texas, USA, had not been exposed to Mycoplasma. Evidence of disease and potential population decline from outbreaks of M. ovipneumoniae are now known from several populations across the Trans‐Pecos Ecoregion with documented instances of pneumonia and bluetongue in desert bighorn sheep from the Van Horn Mountains and Black Gap Wildlife Management Area. These disease events, especially those in 2019–2021, may be a result of increasing populations of aoudad (Ammotragus lervia), an introduced and invasive ungulate, in the region. With large population sizes and similar movement patterns as desert bighorn sheep, aoudad potentially are the reservoirs for bacterial and viral diseases, such as pneumonia and bluetongue, and are possibly contributing to the decline of desert bighorn sheep. Herein, we optimized the multi‐locus sequence typing (MLST) with modifications in the Taq polymerase and annealing temperatures to determine the genetic identity of Mycoplasma strains or species within the nasal passages of desert bighorn sheep and aoudad in the Trans‐Pecos Ecoregion of Texas. Four loci (small ribosomal unit, 16S; 16S‐23S intergenic spacer region, IGS; RNA polymerase B, rpoB; gyrase B, gyrB) were characterized using MLST. Based on results from the modified MLST technique, we identified 9 desert bighorn sheep and 5 aoudad with M. ovipneumoniae, 9 aoudad with bacterial sequences genetically similar to M. conjunctivae, and 10 aoudad with bacterial sequences genetically similar M. hyopneumoniae. Of these, 9 aoudad possessed bacterial sequences genetically similar to both M. conjunctivae and M. hyopneumoniae. Among the 4 diagnostic loci, genetic divergence of M. ovipneumoniae ranged from 0.00–0.90% among desert bighorn sheep and aoudad. Future sampling efforts of seemingly asymptomatic aoudad, and asymptomatic, visibly sick, or deceased desert bighorn sheep, are important to monitor the spread of disease in desert bighorn sheep populations across mountain ranges in western Texas. It is imperative that aoudad removal plans are implemented to reduce and eliminate current infections and putative transmission of M. ovipneumoniae, prevent future disease outbreaks of pneumonia, and ultimately conserve desert bighorn sheep for future generations. [ABSTRACT FROM AUTHOR]

As the main pathogen associated with enzootic pneumonia (EP), Mycoplasma hyopneumoniae (Mhp) is globally prevalent and inflicts huge financial losses on the worldwide swine industry each year. However, the pathogenicity of Mhp has not been fully explained to date. Mhp invasion usually leads to long-term chronic infection and persistent lung colonization, suggesting that Mhp has developed effective immune evasion strategies. In this review, we offer more detailed information than was previously available about its immune evasion mechanisms through a systematic summary of the extant findings. Genetic mutation and post-translational protein processing confer Mhp the ability to alter its surface antigens. With the help of adhesins, Mhp can achieve cell invasion. And Mhp can modulate the host immune system through the induction of inflammation, incomplete autophagy, apoptosis, and the suppression of immune cell or immune effector activity. Furthermore, we offer the latest views on how we may treat Mhp infections and develop novel vaccines. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Veterinary Journal / Revue Vétérinaire Canadienne is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mycoplasma hyopneumoniae (M. hyopneumoniae) is one of the primary agents involved in porcine respiratory disease complex, and circulates in the swine industry worldwide. The prevention and control of M. hyopneumoniae is complicated. Thus, a recombinase-aided amplification (RAA) assay coupled with the clustered regularly-interspaced short palindromic repeats (CRISPR)/Cas12a system was established for the detection of M. hyopneumoniae. The most suitable primer pairs and CRISPR RNA (crRNA) were screened and selected for the RAA-CRISPR/Cas12a detection system. We have achieved a detection limit of 1 copy/µL and 5 copies/µL per reaction for the RAA-CRISPR/Cas12a-fluorescence assay and RAA-CRISPR/Cas12a-lateral flow assay (LFA), respectively. Furthermore, the RAA-CRISPR/Cas12a system displayed no cross-reactivity with other respiratory pathogens. The performance of the RAA-CRISPR/Cas12a system was compared with PCR as recommended by the Chinese national standard (GB/T 35909-2018) and qPCR as recommended by the Chinese entry–exit inspection and quarantine industry standard (SN/T4104-2015) for clinical samples, and good consistency with these methods was observed. Above all, the methods shed a light on the convenient, portable, visual, highly sensitive and specific detection of M. hyopneumoniae, demonstrating a great application potential for on-site monitoring of M. hyopneumoniae in the field.

Abstract Tracheal pooling for Mycoplasma hyopneumoniae (M. hyopneumoniae) DNA detection allows for decreased diagnostic cost, one of the main constraints in surveillance programs. The objectives of this study were to estimate the sensitivity of pooled-sample testing for the detection of M. hyopneumoniae in tracheal samples and to develop probability of M. hyopneumoniae detection estimates for tracheal samples pooled by 3, 5, and 10. A total of 48 M. hyopneumoniae PCR-positive field samples were pooled 3-, 5-, and 10-times using field M. hyopneumoniae DNA-negative samples and tested in triplicate. The sensitivity was estimated at 0.96 (95% credible interval [Cred. Int.]: 0.93, 0.98) for pools of 3, 0.95 (95% Cred. Int: 0.92, 0.98) for pools of 5, and 0.93 (95% Cred. Int.: 0.89, 0.96) for pools of 10. All pool sizes resulted in PCR-positive if the individual tracheal sample Ct value was

Mycoplasma hyopneumoniae is the causative bacterium of porcine enzootic pneumonia and one of the primary etiologic agents of the porcine respiratory disease complex. Most Brazilian commercial pig farms are positive for this pathogen. However, the prevalence of the pathogen in backyard pig farms has not been described, to our knowledge. Therefore, we aimed to determine the prevalence of M. hyopneumoniae in backyard pig farms in the state of Paraná, Brazil. In January–March 2020, we collected 585 serum samples from pigs in 187 non-vaccinated herds. We tested the sera with an indirect ELISA for anti– M. hyopneumoniae antibodies and found that 182 of 585 (31.1%) samples were positive, and were found in 109 of 187 (58.3%) herds assessed. [ABSTRACT FROM AUTHOR]

Mycoplasma hyopneumoniae (Mhp) infection severely affects the daily weight gain and feed-to-meat ratio of pigs, while secondary infections with other pathogens can further lead to increased mortality, causing significant economic losses to the pig industry. CD40L is a molecular adjuvant that enhances the cellular and humoral immune responses to vaccines. In this study, the CD40L peptide was fused to the C-terminus of the chimeric P97R1P46P42 protein by genetic engineering using the pFastBac Dual vector. The recombinant chimeric protein P97R1P46P42 and its fusion P97R1P46P42-CD40L were expressed in Sf9 cells and purified. Mice were immunized with P97R1P46P42 or its fusion protein. Seppic ISA 201 emulsified protein, conventional Mhp vaccine and PBS control groups were included. Immunogenecity was assessed by specific IgG antibody response, splenic lymphocyte proliferation, and cytokine IL-4 and IFN-γ levels. We found that CD40L fusion significantly enhanced specific antibody response, lymphocyte proliferation and IL-4 level in the immunized mouse sera as compared to the P97R1P46P42 or conventional vaccine group. This study provides clear evidence that CD40L potentiates the humoral and cellular immune responses to the Mhp chimeric protein P97R1P46P42 in the mouse model. This CD40L-fused chimeric protein could be a MPS subunit vaccine candidate to be tested for its efficacy in pigs in response to challenges with pathogenic Mycoplasma hyopneumoniae strain(s).

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The goal of this research was to identify lung lesions in slaughtered fatteners originating from registered farms. Evaluation of lung lesions was based on their visible macroscopic features, which were then associated with corresponding diseases. Data on lung lesions in slaughtered fatteners were collected over the period spanning from October to December 2022 from three slaughterhouses (A, B, C), involving 150 fattening animals from each slaughterhouse. The examination of slaughtered pig lungs from all three slaughterhouses in our study revealed that Mycoplasma hyopneumoniae lesions in the lungs are the most prevalent, while Actinobacillus pleuropneumonia and bronchopneumonia occurrences are rare. [ABSTRACT FROM AUTHOR]

Simple Summary: Mycoplasma hyopneumoniae (Mhyo) is a major porcine pathogen worldwide. Understanding its interaction with the pig immune system is crucial for effective disease control. This study evaluates the use of minimal tissue samples from different lung compartments to analyze this interaction in detail, in addition to the microscopic and macroscopic evaluation of lung lesions. Key findings reveal strain-specific virulence variability and a differential cytokine expression in the lung compartments tested, highlighting the relevance of Th1 and Th2, and a potential role for Th17-mediated immune responses in Mhyo infection. The data analyzed shed light on the complex nature of Mhyo infection and its interplay with the pig's immune system, potentially aiding in the development of better disease management strategies. Mycoplasma hyopneumoniae (Mhyo) is the causative agent of porcine enzootic pneumonia (EP), as well as one of the main pathogens involved in the porcine respiratory disease complex. The host–pathogen interaction between Mhyo and infected pigs is complex and not completely understood; however, improving the understanding of these intricacies is essential for the development of effective control strategies of EP. In order to improve our knowledge about this interaction, laser-capture microdissection was used to collect bronchi, bronchi-associated lymphoid tissue, and lung parenchyma from animals infected with different strains of Mhyo, and mRNA expression levels of different molecules involved in Mhyo infection (ICAM1, IL-8, IL-10, IL-23, IFN-α, IFN-γ, TGF-β, and TNF-α) were analyzed by qPCR. In addition, the quantification of Mhyo load in the different lung compartments and the scoring of macroscopic and microscopic lung lesions were also performed. Strain-associated differences in virulence were observed, as well as the presence of significant differences in expression levels of cytokines among lung compartments. IL-8 and IL-10 presented the highest upregulation, with limited differences between strains and lung compartments. IFN-α was strongly downregulated in BALT, implying a relevant role for this cytokine in the immunomodulation associated with Mhyo infections. IL-23 was also upregulated in all lung compartments, suggesting the potential involvement of a Th17-mediated immune response in Mhyo infections. Our findings highlight the relevance of Th1 and Th2 immune response in cases of EP, shedding light on the gene expression levels of key cytokines in the lung of pigs at a microscopic level. [ABSTRACT FROM AUTHOR]

This article introduces a new MfEIT UDESC Mark I system, which consists of a 32-electrode setup featuring a modified Howland current source, low cost, portability, and non-radiation. The system is capable of reconstructing electrical conductivity tomographic images at a rate of 30.624 frames per second, taking about 5 min for imaging. The current source employs a 0.5 mA adjacent current application pattern with frequencies ranging from 10 kHz to 1 MHz. This article outlines the hardware, firmware, and software design specifications, which include the design of the current source, calibration procedures, and image reconstruction process. Tomographic images of conductivity were reconstructed in ex vivo healthy pig lungs and those with pneumonia, as a proof of concept for future applications in live pigs. The high spectral power density, combined with real-time system calibration provides clinical advantages in veterinary medicine. The goal is to identify lung areas affected by Mycoplasma hyopneumoniae in pigs through the analysis of electrical conductivity difference, offering a valuable tool to assist veterinarians to obtain images of respiratory diseases. The modified reconstruction method GREIT (EIDORS) was evaluated with experimental data and was compared with the Gauss–Newton and Total Variation methods, where GREIT 2D proved to be superior. [ABSTRACT FROM AUTHOR]

Currently, the responsible use of antimicrobials in pigs has allowed the continuous development of alternatives to these antimicrobials. In this study, we describe the impact of treatments with two probiotics, one based on live Saccharomyces cerevisiae (S. cerevisiae) and another based on fragmented S. cerevisiae (beta-glucans), that were administered to piglets at birth and at prechallenge with Mycoplasma hyopneumoniae. Thirty-two pigs were divided into four groups of eight animals each. The animals had free access to water and food. The groups were as follows: Group A, untreated negative control; Group B, inoculated by nebulization with M. hyopneumoniae positive control; Group C, first treated with disintegrated S. cerevisiae (disintegrated Sc) and inoculated by nebulization with M. hyopneumoniae; and Group D, treated with live S. cerevisiae yeast (live Sc) and inoculated by nebulization with M. hyopneumoniae. In a previous study, we found that on Days 1 and 21 of blood sampling, nine proinflammatory cytokines were secreted, and an increase in their secretion occurred for only five of them: TNF-α, INF-α, INF-γ, IL-10, and IL-12 p40. The results of the clinical evolution, the degree of pneumonic lesions, and the productive parameters of treated Groups C and D suggest that S. cerevisiae has an immunomodulatory effect in chronic proliferative M. hyopneumoniae pneumonia characterized by delayed hypersensitivity, which depends on the alteration or modulation of the respiratory immune response. The data presented in this study showed that S. cerevisiae contributed to the innate resistance of infected pigs. [ABSTRACT FROM AUTHOR]

Abstract A positive Mycoplasma hyopneumoniae PCR result in a clinical specimen may eventually represent the mere detection of non-viable bacteria, complicating the diagnostic interpretation. Thus, the objective of this study was to evaluate the PCR detection of non-viable M. hyopneumoniae and its residual cell-free DNA in live pigs. Pigs were inoculated with either active or inactivated M. hyopneumoniae and were sampled for up to 14 days. Mycoplasma hyopneumoniae was not detected by PCR at any timepoint in pigs inoculated with the inactivated bacterium, suggesting that in healthy pigs, the non-viable M. hyopneumoniae DNA was rapidly sensed and cleared.

Respiratory diseases, such as pleurisy and pneumonia, cause significant health and economic losses in pig production. This study evaluated 867 finishing pigs from a farm with a history of respiratory issues, using macroscopic lesion scoring (SPES and CVPC), histopathological analysis, qPCR diagnostics, and economic modeling. Severe pleurisy (scores 3 and 4) was observed in 42.1% of carcasses and was strongly correlated with higher bacterial loads of Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, and Pasteurella multocida. Severe lesions reduced the average daily gain (ADG) and carcass weight, leading to increased production costs and lower profitability. Economic analysis revealed that pigs with higher pleurisy scores incurred an additional cost per kg (USD 1.29 vs. USD 1.32 for milder cases), reduced total revenue by 1.36%, and decreased return on investment (ROI) from 5.33% to 3.90%. These findings emphasize the critical impact of respiratory diseases on profitability and the necessity of robust health management strategies, including vaccination and enhanced biosecurity, to minimize economic losses in swine farming.

Mycoplasma hyopneumoniae, an important cause of enzootic pneumonia in pigs in many countries, has recently been shown to exhibit reduced susceptibility to several antimicrobial classes. In the present study, a total of 185 pig lung tissue samples were collected from abattoirs in Australia, from which 21 isolates of M. hyopneumoniae were obtained. The antimicrobial resistance profile of the isolates was determined for 12 antimicrobials using minimum inhibitory concentration (MIC) testing, and a subset (n = 14) underwent whole-genome sequence analysis. MIC testing revealed uniformly low values for enrofloxacin (≤1 μg/mL), florfenicol (≤8 μg/mL), lincomycin (≤4 μg/mL), spectinomycin (≤4 μg/mL), tetracycline (≤0.5 μg/mL), tiamulin (≤2 μg/mL), tildipirosin (≤4 μg/mL), tilmicosin (≤16 μg/mL) tulathromycin (≤2 μg/mL), and tylosin (≤2 μg/mL). Higher MICs were observed for erythromycin (MIC range: 16–32 μg/mL), gamithromycin, and tilmicosin (MIC range of both: 32–64 μg/mL). Whole-genome sequencing of the isolates and additional screening using mismatch amplification mutation assay PCR did not identify any known genetic resistance markers within 23S rRNA (macrolides), DNA gyrase A, and topoisomerase IV genes (fluoroquinolones). The WGS data also indicated that the Australian M. hyopneumoniae isolates exhibited limited genetic diversity and formed a distinct monophylectic clade when compared to isolates from other countries. These findings indicate that Australian M. hyopneumoniae likely remains susceptible to the major antimicrobials used to treat enzootic pneumonia in pigs and have evolved in isolation from strains identified in other pig-producing countries.

Antimicrobial resistance (AMR) in Mycoplasma hyopneumoniae, the causative agent of Enzootic Pneumonia in swine, poses a significant challenge to the swine industry. This review focuses on the genetic foundations of AMR in M. hyopneumoniae, highlighting the complexity of resistance mechanisms, including mutations, horizontal gene transfer, and adaptive evolutionary processes. Techniques such as Whole Genome Sequencing (WGS) and multiple-locus variable number tandem repeats analysis (MLVA) have provided insights into the genetic diversity and resistance mechanisms of M. hyopneumoniae. The study underscores the role of selective pressures from antimicrobial use in driving genomic variations that enhance resistance. Additionally, bioinformatic tools utilizing machine learning algorithms, such as CARD and PATRIC, can predict resistance traits, with PATRIC predicting 7 to 12 AMR genes and CARD predicting 0 to 3 AMR genes in 24 whole genome sequences available on NCBI. The review advocates for a multidisciplinary approach integrating genomic, phenotypic, and bioinformatics data to combat AMR effectively. It also elaborates on the need for refining genotyping methods, enhancing resistance prediction accuracy, and developing standardized antimicrobial susceptibility testing procedures specific to M. hyopneumoniae as a fastidious microorganism. By leveraging contemporary genomic technologies and bioinformatics resources, the scientific community can better manage AMR in M. hyopneumoniae, ultimately safeguarding animal health and agricultural productivity. This comprehensive understanding of AMR mechanisms will be beneficial in the adaptation of more effective treatment and management strategies for Enzootic Pneumonia in swine.

Mycoplasma hyopneumoniae (M. hyo) causes significant losses to the economy of the pig industry in the world. Little information is available about the prevalence of M. hyo infection in Chinese native pigs. We report herein a high seroprevalence (61.5%) to M. hyo in Chinese native pigs (Meishan and Fengjing) from Shanghai, China. Meishan or Fengjing pigs had a significantly higher seroprevalence compared to Duroc x Landrace x Yorkshire pigs (p<0.05). Among Meishan and Fengjing groups, the peak prevalence was in breeding pigs (74.5%), followed by suckling piglets (71.4%), finishing pigs (69.6%) and nursery pigs (34.7%) and differences were statistically significant (p<0.05). PCR analysis of the nasal swabs showed that 5.1% (5/98) of the Meishan pigs (6.5%, 3/46) or Fengjing pigs (3.8%, 2/52) were positive for M. hyo. The nucleotide sequences of p46 genes of M. hyo from Meishan pigs or Fengjing pigs were highly conserved with 98.6-99.8% sequence homology with other reference strains. Our data confirm that M. hyo infection in native pigs was highly prevalent in Shanghai, and thus integrated strategies should be taken to control the disease. [ABSTRACT FROM AUTHOR]

Mycoplasma hyopneumoniae (Mhyo) is primary pathogen involved in porcine respiratory diseases complex (PRDC). The objective of this study was to evaluate Mycoplasma hyopneumoniae (Mhyo) infection in five commercial pig farms by using serology and lung lesion scoring at slaughter. Five Macedonian pig herds with a history of respiratory diseases were included in the study. Blood samples were taken from pigs at 6, 10, 14, 18, and 22 weeks of age. Ten animals per age group from each farm were sampled and tested for antibodies to Mhyo. At abattoir, 50 lungs per farm were scored for lesions associated with enzootic pneumonia (EP). All farms were seropositive to Mhyo. Higher seroprevalence to Mhyo was observed in grower and finisher pigs, while significant difference (p10) were found among some of the farms (p

This study was aimed to identification and detection of Mycoplasma dispar by conventional real-time polymerase chain reaction (PCR) assays followed by routine hematoxylin & eosin technique to further confirmation of Mycoplasma species related to the lesions observed in diseased calves. Ten samples of infected lung tissue were gathered and fixed in 10% neutral buffered formalin and handled for making a microscopic slide after confirming Mycoplasma dispar infection by PCR. Histopathological examination of the lung revealed two types of pneumonia; chronic suppurative pneumonia in 60% of the cases and 40% of diffuse interstitial pneumonia. Mycoplasma dispar was confirmed based on genetic analysis. Slemani/2018 field isolate showed 99.84% homologies with four reference isolates of Mycoplasma dispar in NCBI GenBank. Phylogenetic analysis indicated a close relation to Mycoplasma ovipneumoniae, Mycoplasma hyopneumoniae, and Mycoplasma flocculare, often isolated from sheep and goats. Therefore, further study is crucial to identify Iraqi livestock's circulating Mycoplasma species related to respiratory diseases. [ABSTRACT FROM AUTHOR]

A positive Mycoplasma hyopneumoniae PCR result in a clinical specimen may eventually represent the mere detection of non-viable bacteria, complicating the diagnostic interpretation. Thus, the objective of this study was to evaluate the PCR detection of non-viable M. hyopneumoniae and its residual cell-free DNA in live pigs. Pigs were inoculated with either active or inactivated M. hyopneumoniae and were sampled for up to 14 days. Mycoplasma hyopneumoniae was not detected by PCR at any timepoint in pigs inoculated with the inactivated bacterium, suggesting that in healthy pigs, the non-viable M. hyopneumoniae DNA was rapidly sensed and cleared. [ABSTRACT FROM AUTHOR]

Twenty-eight mixed-parity sows (Line 241; DNA) and their offspring were used to evaluate live yeast supplementation during lactation with or without a pre/probiotic combination during the nursery period on lactation performance, lifetime growth performance, and immune response. On day 110 of gestation, sows were allotted to a lactation diet with or without a live yeast probiotic (0.10% Actisaf Sc 47 HR+; Phileo by Lesaffre, Milwaukee, WI). At weaning, their offspring (350 pigs; initially 6.1 ± 0.02 kg) were randomly assigned in a 2 × 2 factorial with main effects of sow treatment and nursery treatment consisting of a control diet or a diet with a yeast cell wall prebiotic and Bacillus subtilis probiotic (0.10% YB; Phileo by Lesaffre, Milwaukee, WI) fed for 42 d followed by common diets fed until marketing. Two nursery pens were combined into 1 finishing pen, such that there were 5 and 10 pigs per pen with 17 or 18 and 8 or 9 replications per treatment during the nursery and finishing periods, respectively. There were no significant effects of yeast supplementation on lactation performance (P  ≥ 0.079). There was a sow × nursery diet interaction (P  = 0.024) on nursery ADG. Pigs from yeast-fed sows had increased ADG when fed control nursery diets compared to pigs from control sows fed the control nursery diet with pigs fed pre/probiotic nursery diets intermediate, regardless of sow diet. Pigs from yeast-fed sows tended (P  = 0.067) to have greater final body weight (BW) (day 165). A subset of pigs was sampled throughout their lifetime to determine serum porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae antibody sample-to-positive (S/P) ratios and percentage inhibition of Lawsonia intracellularis. There was a tendency for a PCV2 S/P ratio sow diet × day interaction (P  = 0.097) where progeny from yeast-fed sows had higher PCV2 S/P ratios at 101 d of age compared to control sow progeny (P  = 0.046). There was a PCV2 S/P ratio nursery diet × day interaction (P  = 0.036) where pigs fed a pre/probiotic combination had reduced S/P ratios at 66, 78, and 162 d of age (P  ≤ 0.022); however, at 22 d of age pigs fed a pre/probiotic combination tended to have an increased S/P ratio (P  = 0.051). In conclusion, the effects of combining a yeast probiotic in lactation diets and a pre/probiotic in nursery diets were not additive. However, feeding a live yeast probiotic during lactation resulted in tendencies (P  ≤ 0.10) for increased progeny final BW and hot carcass weight. [ABSTRACT FROM AUTHOR]

As the main pathogen associated with enzootic pneumonia (EP), Mycoplasma hyopneumoniae (Mhp) is globally prevalent and inflicts huge financial losses on the worldwide swine industry each year. However, the pathogenicity of Mhp has not been fully explained to date. Mhp invasion usually leads to long-term chronic infection and persistent lung colonization, suggesting that Mhp has developed effective immune evasion strategies. In this review, we offer more detailed information than was previously available about its immune evasion mechanisms through a systematic summary of the extant findings. Genetic mutation and post-translational protein processing confer Mhp the ability to alter its surface antigens. With the help of adhesins, Mhp can achieve cell invasion. And Mhp can modulate the host immune system through the induction of inflammation, incomplete autophagy, apoptosis, and the suppression of immune cell or immune effector activity. Furthermore, we offer the latest views on how we may treat Mhp infections and develop novel vaccines.

Mycoplasma hyopneumoniae (M. hyopneumoniae) is considered the primary causative agent of porcine enzootic pneumonia (EP), a chronic contagious respiratory disease that causes economic losses. Obtaining new pathogenic isolates and studying the genome and virulence factors are necessary. This study performed a complete sequencing analysis of two Brazilian strains, UFV01 and UFV02, aiming to characterize the isolates in terms of the virulence factors and sequence type. The complete genome analysis revealed the main virulence genes (mhp385, mhp271, MHP_RS03455, p102, p97, p216, MHP_RS00555, mhp107) and ST-123, the presence of three toxin-related genes (tlyC, PLDc_2 and hcnC), and some genetic groups specific to these two isolates. Subsequently, the pathogenicity of the isolates was evaluated via an experimental infection conducted in a swine model. The study was divided into three groups, namely a negative control group (n  =  4) and two test groups (n  =  8), totaling 20 animals. They were challenged at 35  days of age with 107 CCU (Color Changing Units) M. hyopneumoniae via the intratracheal route. The UFV01 group showed earlier and higher seroconversion (IgG) (100%), while only 50% of the UFV02 group seroconverted. The same trend was observed when analyzing the presence of IgA in the bronchoalveolar lavage fluid (BALF) at 35  days post-infection (dpi). The UFV01 group had a mean macroscopic lesion score of 11.75% at 35 dpi, while UFV02 had 3.125%. Microscopic lesions were more severe in the UFV01 group. Based on laryngeal swab samples evaluated by qPCR, and the detection began at 14  days. The UFV01 group showed 75% positivity at 14 dpi. The UFV02 group also started excreting at 14 dpi, with a positivity rate of 37.5%. The results indicate that the UFV01 isolate exhibits higher virulence than UFV02. These findings may aid in developing new vaccines and diagnostic kits and establishing experimental models for testing. [ABSTRACT FROM AUTHOR]

Pneumonia has been identified as one of the limiting factors to pig production. Some of the pneumonia-inducing agents include Mycoplasma hyopneumoniae (MHYO), the primary cause of enzootic pneumonia and Metastrongylus species. which are widely distributed lungworms commonly found in indigenous free-range pigs. This paper describes the pathological findings of 6 cases out of 204 lungs randomly collected from slaughtered pigs in Southwest Nigeria. Samples of the lungs were collected from the cases for bacterial culture, histopathology and detection of MHYO antigens using immunohistochemisty. Gross lesions were severe acute lobular bronchopneumonia (104/204, 50.98%) and greyish discrete nodules in the lungs. Microscopically, there were varying degrees of lymphoid hyperplasia of bronchial-associated lymphoid tissue (BALT) (82.2%), suppurative bronchiolitis with widespread bronchiolar epithelial cells necrosis (57.4%) and granulomatous bronchopneumonia with presence of Metastrongylus spp. and bronchiolar intraluminal cellular exudate consisting predominantly of eosinophils (2.9%). Pasteurella multocida was the most isolated bacterial pathogen (49.0%) either as a single pathogen or in combination with other pathogens from the infected lung samples. Immunohistochemical labelling showed strong MHYO antigens on the surface of bronchial epithelial cells in infected lungs (86/204). This is the first report of granulomatous bronchopneumonia due to Metastrongylus spp. associated with a coinfection of MHYO and Pasteurella multocida in Nigerian indigenous pigs. It is suggested that metastrongylosis may be more common than reported in this study. The detection of respiratory pathogens such as Mycoplasma. hyopneumoniae, Metasrongylus spp. and Pasteurella multocida suggest that they are potential contributors to bronchopneumonia observed in this study. [ABSTRACT FROM AUTHOR]

The pork industry is an essential part of the global food system, providing a significant source of protein for people around the world. A major factor restraining productivity and compromising animal wellbeing in the pork industry is disease outbreaks in pigs throughout the production process: widespread outbreaks can lead to losses as high as 10% of the U.S. pig population in extreme years. In this study, we present a machine learning model to predict the emergence of infection in swine production systems throughout the production process on a daily basis, a potential precursor to outbreaks whose detection is vital for disease prevention and mitigation. We determine features that provide the most value in predicting infection, which include nearby farm density, historical test rates, piglet inventory, feed consumption during the gestation period, and wind speed and direction. We utilize these features to produce a generalizable machine learning model, evaluate the model's ability to predict outbreaks both seven and 30 days in advance, allowing for early warning of disease infection, and evaluate our model on two swine production systems and analyze the effects of data availability and data granularity in the context of our two swine systems with different volumes of data. Our results demonstrate good ability to predict infection in both systems with a balanced accuracy of 85.3 % on any disease in the first system and balanced accuracies (average prediction accuracy on positive and negative samples) of 58.5 % , 58.7 % , 72.8 % and 74.8 % on porcine reproductive and respiratory syndrome, porcine epidemic diarrhea virus, influenza A virus, and Mycoplasma hyopneumoniae in the second system, respectively, using the six most important predictors in all cases. These models provide daily infection probabilities that can be used by veterinarians and other stakeholders as a benchmark to more timely support preventive and control strategies on farms. [ABSTRACT FROM AUTHOR]