Search Results (53)

Wild boar (Sus scrofa) is a widespread invasive species in Poland and may act as a reservoir for various pathogens, including those associated with the porcine respiratory disease complex (PRDC). As data on bacterial respiratory pathogens in wild boar populations, particularly co-infections, in Poland and other European countries remain limited, the main goal of our study was to examine the frequency of selected bacterial respiratory agents and their co-occurrence in lung samples collected from culled wild boars during hunting. Two hundred and fifty-three lung samples were analysed for the presence of genetic material of A. pleuropneumoniae, M. hyopneumoniae, M. hyorhinis, and G. parasuis. In total, 159 out of the 253 (62.8%; 95% CI: 56.6–68.8) wild boars were infected with at least one pathogen. In general, 73 (28.9%; 95% CI: 23.3–34.9) of wild boar lung samples tested positive for G. parasuis, 106 (41.9%; 95% CI: 35.7–48.2) were positive for M. hyopneumoniae, and 10 (4%; 95% CI: 1.9–7.1) were positive for M. hyorhinis. No evidence of A. pleuropneumoniae infection was detected in any of the examined lung samples. Infection with a single pathogen was detected in 129 (51%; 95% CI: 44.6–57.3) of sampled wild boars, whereas co-occurrence of two infectious bacterial agents was revealed in 30 animals (11.9%; 95% CI: 8.1–16.5). Among single-pathogen infections, the highest positivity rate was observed for M. hyopneumoniae (31.6%; 95% CI: 25.9–37.7), whereas the most frequent co-infection involved M. hyopneumoniae and G. parasuis (9.1%; 95% CI: 5.8–13.3). This investigation indicated that wild boar in the study area are potential hosts for bacterial agents associated with PRDC. It is worth highlighting that wild boars can contribute to the maintenance and/or dissemination of bacterial pathogens to humans (especially hunters) and domestic animals, and it is essential to maintain active surveillance of these infectious agents. Full article

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses for the global swine industry. Gilt immunization using modified live virus (MLV) vaccines is crucial for herd stability, but it is complicated by frequent mixed infections of PRRSV strains on farm. This study monitored the administration of tylvalosin during a PRRSV-2 MLV (TJM) immunization program, focusing on viral dynamics and immune responses in gilts naturally exposed to co-circulating classical (GD240101) and highly pathogenic like (HP-PRRSV-like, GD240102) PRRSV strains. Methods: The animal study was approved by the Laboratory Animal Ethical Committee of China Agricultural University. One hundred gilts were randomized into control and tylvalosin groups (n = 50/group). All received the TJM MLV vaccination. The tylvalosin group received tylvalosin tartrate premix cyclically in-feed for three cycles. Serum and saliva samples were collected periodically. PRRSV RNA (RT-qPCR) and specific antibodies (ELISA) were assessed. Viral population dynamics (relative abundance, mutation, recombination of TJM, GD240101, and GD240102) were monitored via next-generation sequencing (NGS) on a pooled PRRSV-positive sample. Results: In this field trial where tylvalosin was used, a shorter duration of PRRSV viremia and saliva shedding was observed to compare with controls. NGS analysis showed accelerated vaccine strain (TJM) clearance in the tylvalosin group (by week 3 vs. week 9 in control). Field strain dynamics were also altered, showing a faster decline in the tylvalosin group. Antibody response uniformity was altered, with lower coefficient of variation (CV) for PRRSV and CSFV observed following tylvalosin usage. Conclusions: In gilts receiving tylvalosin for the management of bacterial pathogens during a PRRSV MLV immunization program, it was associated with accelerated viral clearance and enhanced systemic immune response uniformity under mixed-infection field conditions. NGS provides invaluable data for dissecting these complex viral dynamics. Crucially, these findings describe a biological drug–host–virus interaction and should not be interpreted as an endorsement for the prophylactic use of antimicrobials. In alignment with global antimicrobial stewardship principles, tylvalosin should be reserved for the therapeutic treatment of diagnosed bacterial diseases to mitigate the risk of promoting resistance. Full article

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. Full article

The seasonal patterns of viral diseases in farm animals present significant challenges to global livestock productivity, with cold stress emerging as a potential modulator of host–pathogen interactions. This review synthesizes current knowledge on the expression dynamics of heat shock protein 70 (HSP70) in farm animals under cold-stress conditions and its potential roles as (1) a viral replication facilitator and (2) an immune response regulator. This review highlights cold-induced HSP70 overexpression in essential organs, as well as its effects on significant virus life cycles, such as porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome virus (PRRSV), and bovine viral diarrhea virus (BVDV), through processes like viral protein chaperoning, replication complex stabilization, and host defense modulation. By integrating insights from thermophysiology, virology, and immunology, we suggest that HSP70 serves as a crucial link between environmental stress and viral disease seasonality. We also discuss translational opportunities targeting HSP70 pathways to break the cycle of seasonal outbreaks, while addressing key knowledge gaps requiring further investigation. This article provides a framework for understanding climate-driven disease patterns and developing seasonally adjusted intervention strategies. Full article

Background/Objectives: The porcine respiratory disease complex (PRDC) is a multifaceted, polymicrobial syndrome resulting from a combination of environmental stressors, primary infections (e.g., PRRSV) and secondary infectious agents (viruses and bacteria). PRDC causes severe lung pathology, leading to reduced performance, increased mortality rates, and higher production costs in the global pig industry. Our goal was to conduct a comprehensive study correlating both the anti-PRRSV immune response and 21 secondary infectious agents with PRDC severity. Methods: To this end, PRRSV-negative weaners were vaccinated with a PRRSV-2 MLV and put into a farm with a history of PRDC. Subsequently, anti-PRRSV cellular and antibody responses were monitored pre-vaccination, at 28 days post vaccination (dpv) and during PRDC outbreak (49 dpv). NanoString was used to quantify 21 pathogens within the bronchoalveolar lavage (BAL) at the time of necropsy (51 dpv). PRRSV-2 was present in 53 out of 55 pigs, and the other five pathogens (PCMV, PPIV, B. bronchiseptica, G. parasuis, and M. hyorhinis) were detected in BAL samples. Results: Although the uncontrolled settings of field trials complicated data interpretation, multivariate correlation analyses highlighted valuable lessons: (i) high weaning weight predicted animal resilience to disease and high weight gains correlated with the control of the PRRSV-2 field strain; (ii) most pigs cleared MLV strain within 7 weeks, and the field PRRSV-2 strain was the most prevalent lung pathogen during PRDC; (iii) all pigs developed a systemic PRRSV IgG antibody response which correlated with IgG and IgA levels in BAL; (iv) the induction of anti-field strain-neutralizing antibodies by MLV PRRSV-2 vaccination was both late and limited; (v) cellular immune responses were variable but included strong systemic IFN-γ production against the PRRSV-2 field strain; (vi) the most detected lung pathogens correlated with PRRSV-2 viremia or lung loads; (vii) within the six detected pathogens, two viruses, PRRSV-2 and PCMV, significantly correlated with the severity of the clinical outcome. Conclusions: While a simple and conclusive answer to the multifaceted nature of PRDC remains elusive, the key lessons derived from this unique study provide a valuable framework for future research on porcine respiratory diseases. Full article

Background: Porcine Reproductive and Respiratory Syndrome (PRRS) is a highly contagious disease characterized by reproductive failure in sows and severe respiratory disorders across all swine ages, causing significant economic losses. In China, the PRRSV epidemiological landscape is complex, with the coexistence of multiple lineages and frequent recombination. The major circulating strains include sublineages 1.8 (NADC30-like PRRSV) and 1.5 (NADC34-like PRRSV), along with lineages 8 (HP-like PRRSV) and 5 (VR2332-like PRRSV), highlighting the urgent need for rapid detection and lineage differentiation. Methods: A quadruplex RT-qPCR assay was developed targeting lineage-specific deletions in the NSP2 gene to simultaneously detect PRRSV-2 and differentiate NADC30-like PRRSV, HP-like PRRSV, and NADC34-like PRRSV strains. The assay was optimized with respect to reaction conditions, including annealing temperature, primers, and probe concentrations. The method’s performance was evaluated in terms of specificity, sensitivity, repeatability, stability, limit of detection (LOD), and consistency with sequencing results. Results: The assay demonstrated high sensitivity (LOD of 3 copies/μL), high specificity, and good repeatability (coefficient of variation < 1.5%). Field application using 938 samples from Guangxi A and B farms revealed NADC30-like PRRSV wild-type strains at positivity rates of 13.44% and 3.53%, respectively. Positive samples selected for sequencing were further confirmed using ORF5-based phylogenetic analysis and NSP2 deletion pattern comparison, which aligned with RT-qPCR detection results. Field application primarily detected NADC30-like PRRSV, while further validation is still needed for HP-like and NADC34-like strains. The developed quadruplex RT-qPCR assay enables rapid and simultaneous detection of PRRSV-2 and differentiation of three major lineages, providing a sensitive, specific, and reliable tool for distinguishing vaccine-derived from circulating strains and supporting targeted disease surveillance and control in swine farms. Full article

Mycoplasma hyopneumoniae (Mhyo) and porcine circovirus type 2 (PCV2) are critical pathogens in the swine industry, both contributing significantly to the porcine respiratory disease complex (PRDC). Given their impact, it is logical to control these pathogens simultaneously. Consequently, combined vaccinations against Mhyo and PCV2 are gaining popularity in swine health management. We present the efficacy of the first commercial combined vaccine prepared of a genotype PCV2d strain and Mhyo and tested against experimental challenge infections with target pathogens in comparative trials with other commercial products. In these studies, three-week-old piglets were vaccinated according to the manufacturers’ instructions. Five weeks later, they were challenged with two Mhyo strains over three consecutive days or with a PCV2d strain once. Positive controls included challenged pigs without prior vaccination, while non-vaccinated/non-challenged pigs served as negative controls. The key parameters measured were lung lesion scores and seroconversion for Mhyo, and viraemia, rectal shedding, lymph node and lung viral content, and seroconversion for PCV2. Findings and conclusion: The results showed no compromising effects between the vaccine components and highlighted significant differences in efficacy among the various products tested. Additionally, oral fluid sampling demonstrated a strong correlation with the viraemia and fecal shedding of PCV2, underscoring the diagnostic and animal welfare benefits of this sampling method. Full article

Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (MHP) are both important and common pathogens in the pig industry. Both pathogens are major contributors to the porcine respiratory disease complex and serve to potentiate other bacterial infections such as Actinobacillus pleuropneumonia. This study aims to evaluate the efficacy of a ready-to-use bivalent PCV2 and MHP vaccine in the field under naturally PCV2-infected farms against existing monovalent options. We evaluated PCV2 viremia, PCV2 antibodies, and lung lesion scores in slaughtered pigs in our study across four farms in Taiwan. Our results found that in two out of four farms, the piglets vaccinated with Porcilis^® PCV M Hyo had superior whole-life PCV2 viremia reduction compared to the existing vaccination program on farms. In the lung lesion scoring, the Porcilis^® PCV M Hyo group had significantly lower Actinobacillus pleuropneumonia-type lesions in pigs than in the competitor group in two out of three farms evaluated. In this field trial, Porcilis^® PCV M Hyo proved to be efficacious in protecting piglets against both PCV2 viremia and the impact of MHP secondary infection, in the context of a reduction in viremia and reduced APP-like lesions found at slaughter. Full article

Porcine reproductive and respiratory syndrome (PRRS) is an infectious disease that can cause reproductive disorders in sows and affect the breathing of piglets, seriously endangering pig breeding worldwide. In this study, Lactobacillus plantarum NC8 was used as the expression delivery vector of foreign proteins, and a single-chain antibody was designed based on an mAb-PN9cx3 sequence. Three recombinant strains of Lactobacillus plantarum, namely, NC8/pSIP409-pgsA‘-PN9cx3-scFV(E), NC8/pSIP409-pgsA’-PN9cx3-HC(E), and NC8/pSIP409-pgsA‘-PN9cx3-LC(E), were successfully constructed. In an in vitro test, the viral load of each experimental group was significantly lower than that of the control group (p < 0.01). In the piglet challenge protection test, the percentage of CD3⁺CD8⁺T cells in the blood of piglets given complex lactic acid bacteria was significantly increased before and after the challenge (p < 0.01); the body temperature of piglets in this group was normal, the viral load of each organ was reduced, and the obvious pathological changes in each tissue were alleviated. At the same time, the abundance of Bacteroides, Fusobacterium, and other bacteria in the intestinal tracts of the piglets changed, affecting the metabolism of carbohydrates and amino acids and the differentiation of Th1 and Th2 cells. This experiment provides a feasible strategy and method for the design of a PRRSV vaccine. Full article

Viruses in the Circoviridae family can infect mammals and birds. Porcine circovirus type 2 (PCV2) significantly affects the livestock industry by causing porcine circovirus-associated diseases, such as postweaning multisystem wasting syndrome, respiratory disease complex, and dermatitis nephropathy syndrome. Additionally, beak and feather disease virus in parrots, canine circovirus in dogs, and columbid circovirus (pigeon circovirus) in racing pigeons induce immunosuppression, followed by secondary infections in these hosts. Although the PCV2 capsid protein has been demonstrated to inhibit type I interferon (IFN) signaling, the molecular mechanisms of Circoviridae-induced immunosuppression are largely unknown. In this study, we examined whether these functions are conserved across Circoviridae capsid proteins. Our results illustrated that although the nuclear localization of capsid proteins is conserved, their effects on IFN-β signaling vary by species, revealing the diverse roles of Circoviridae capsid proteins in modulating immune responses. Full article

Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive disorders in sows and severe pneumonia in piglets, alongside immunosuppressive effects on the host. It poses a significant global threat to the swine industry, with no effective control measures currently available due to its complex pathogenesis and high variability. Conventional inactivated and attenuated vaccines provide inadequate protection and carry biosafety risks. In this study, we designed a universal multi-epitope peptide vaccine against PRRSV using bioinformatics and immunoinformatics approaches to address these limitations. By selecting sequences from seven representative PRRSV strains, we predicted highly conserved and immunogenic T cell (Th and CTL) epitopes across all encoded proteins. These were rationally concatenated with reported B cell neutralizing epitopes into a multi-epitope vaccine construct. We performed comprehensive assessments of the construct’s physicochemical and biochemical properties, along with predictions and refinements of its secondary and tertiary structures. Molecular docking simulations with TLR2 and TLR4 revealed strong potential binding interactions. Immune simulations indicated that the multi-epitope vaccine could induce robust humoral and cellular immune responses. This study provides a scientific foundation for the development of safe and effective PRRSV subunit vaccines and offers new perspectives for designing vaccines against other viral diseases. Full article

The nasal mucosa is a crucial filtering organ to prevent attachment and invasion of pathogens. To assess nasal health in relation to lung health, transverse cross sections of the nasal turbinates of 121 pigs suffering from respiratory disease and sent for diagnostic necropsy were scored visually and by an artificial intelligence (AI) medical diagnostic application (AI DIAGNOS), resulting in a high correlation of both scores (p < 0.001). Nasal samples of the diseased pigs were examined only for Bordetella (B.) bronchiseptica (PCR and bacteriological culture) and Pasteurella (P.) multocida (bacteriological culture). All pigs showed various degrees of inflammatory lung tissue alterations, and 35.5% of the pigs had atrophy of the nasal turbinates with no relation to detection rates of B. bronchiseptica (54.5%) and P. multocida (29.0%) in the nose. All P. multocida strains from nose samples were negative for the toxA gene so non-progressive atrophic rhinitis was diagnosed. Pigs positive for B. bronchiseptica in the nose were more often positive for B. bronchiseptica in the lung (p < 0.001) and for other bacterial species in the lower respiratory tract (p = 0.005). The new diagnostic application for scoring cross sections of nasal turbinates is a valuable tool for a fast and reproducible diagnostic. Full article

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. Full article

Glaesserella (Haemophilus) parasuis, the causative agent of Glässer’s disease, is present in most pig farms as an early colonizer of the upper respiratory tract. It exhibits remarkable variability in virulence and antimicrobial resistance (AMR), with virulent strains capable of inducing respiratory or systemic disease. This study aimed to characterize the virulence and the AMR profiles in 65 G. parasuis isolates recovered from Spanish swine farms. Virulence was assessed using multiplex leader sequence (LS)-PCR targeting vtaA genes, with all isolates identified as clinical (presumed virulent). Pathotyping based on ten pangenome genes revealed the virulent HPS_22970 as the most frequent (83.1%). Diverse pathotype profiles were observed, with 29 unique gene combinations and two isolates carrying only potentially non-virulent pangenome genes. AMR phenotyping showed widespread resistance, with 63.3% classified as multidrug resistant, and high resistance to clindamycin (98.3%) and tylosin (93.3%). A very strong association was found between certain pathotype genes and AMR phenotypes, notably between the virulent HPS_22970 and tetracycline resistance (p < 0.001; Φ = 0.58). This study reveals the wide diversity and complexity of G. parasuis pathogenicity and AMR phenotype, emphasizing the need for the targeted characterization of clinical isolates to ensure appropriate antimicrobial treatments and the implementation of prophylactic measures against virulent strains. Full article

Diseases in the swine industry can cause significant economic and health impacts. This review examines R₀ estimates for respiratory diseases in pigs, assessing variations and comparing transmission risks within and between farms. A literature search of three databases aggregated peer-reviewed research articles on swine viral respiratory diseases’ R₀ values. The study focused on seven diseases: Aujeszky’s disease (AD), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), Circovirus, Influenza A (IA), Encephalomyocarditis Virus (EV), Classical Swine Fever (CSF), and African Swine Fever (ASF). R₀ values were estimated for transmission within and between herds/farms using various methods, from complex mathematical models to simple calculations. Data primarily came from disease surveillance and laboratory experiments. The median R₀ for within-herd and between-herd transmission was 10 and 3.31 for AD, 2.78 and 1.14 for PRRSV, 5.9 and 0.89 for Circovirus, 1.75 and 1.6 for CSF, and 3.94 and 3.15 for ASF. For IA and EV, only within-herd R₀ values were estimated at 8.65 and 1.3, respectively. Diseases with high R₀ values highlight the need for prompt detection and response to outbreaks. Continuous monitoring and evaluation of pathogen transmissibility are crucial for enhancing disease surveillance and reducing the impact of livestock diseases. Full article