Lawsonia Intracellularis (L. intracellularis) is an obligate intracellular bacterium that causes porcine proliferative enteropathy. In this study, a pan-RV (reverse vaccinology based on pangenome analysis) approach was applied to analyze the whole-genome sequences of 9 L. intracellularis strains downloaded from the National Center of Biotechnology Information (NCBI) server. Pangenome analysis revealed a closed pangenome and a core genome consisting of 1372 genes, while reverse vaccinology further revealed 16 candidate proteins with higher in silico immunogenicity parameters, including predicted antigenicity, "outer membrane protein" or "extracellular protein" by subcellular localization analysis and no more than 2 transmembrane regions by transmembrane helices prediction. Three of the 16 proteins that showed no homology with proteins of other species according to BLAST (Basic Local Alignment Search Tool) were selected for serological validation. The Western blotting results revealed that the 3 proteins did not cross-react with anti-Shigella and anti-Salmonella sera, with 1 protein (LAW_RS03650) showed antigenicity when it reacted with positive wild-type anti-L. intracellularis serum. The immunofluorescence of infected cells employing anti-LAW_RS03650 serum indicated a wide distribution of LAW_RS03650 protein in the host cells and L. intracellularis itself. This study identified a novel L. intracellularis antigen, LAW_RS03650, as a candidate for future recombinant vaccine development or species-specific serodiagnostic reagents.

First evidence of Lawsonia intracellularis detection in air from commercial swine farms.

Vaccination is a tool to control Lawsonia intracellularis (LI) in pigs. However, pigs may have co-infections that worsen clinical signs and lesions. The aim of this study was to characterize systemic and gut-mediated humoral and cell-mediated immune (CMI) responses in pigs vaccinated with a killed intramuscular LI vaccine and to analyze the impact of co-infection with Brachyspira hyodysenteriae (Bhyo) on the immune response. The study included eighty pigs and five study groups: V-CO (LI-vaccinated and co-infected with LI + Bhyo, n = 21), P-CO (placebo and co-infected with LI + Bhyo, n = 18), V-LI (LI-vaccinated and infected with LI, n = 21), P-LI (placebo and infected with LI, n = 12), and NC (negative control, placebo and non-challenged, n = 8). Parameters analyzed: fecal score and pathogen shedding), gross intestinal lesions, LI intestinal colonization (IHC), serum IgG, LI-specific IFN-γ production (ELISPOT), and immune cell subsets (flow cytometry) in blood, mesenteric lymph nodes, Peyer's patches, and intestinal epithelium. LI vaccination significantly reduced LI fecal shedding, intestinal colonization, and macroscopic lesions-even under Bhyo co-infection. Vaccinated pigs had earlier and stronger serum IgG and IFN-γ responses. B cells seem to play an important role in the local immune response, and T regulatory cells apparently do not have a significant role in immunomodulation. This study contributes to a better understanding of LI immune response and can provide subtract for further research in the control of LI.

Background/Objectives: Lawsonia intracellularis (L. intracellularis) is an important intestinal pathogen that causes porcine proliferative enteropathy (PPE) in swine production worldwide. Currently, only a few commercially available vaccines are available for PPE prevention. Methods: In this study, an attenuated L. intracellularis variant of JS-G90 was obtained through subculturing of L. intracellularis JS isolates in McCoy cells for 90 generations, and its immune response was evaluated in pigs. Results: The results demonstrated that pigs who underwent intragastric administration of JS-G90 had lower fecal bacterial shedding and no histopathological lesions, indicating that it was safe in pigs. Therefore, JS-G90 was selected to develop the attenuated PPE vaccine. The immune response of JS-G90 in pigs was further evaluated based on fecal bacterial shedding, histopathological lesions, and humoral and cell-mediated immune responses following challenge with pathogenic L. intracellularis. The results revealed that JS-G90 significantly decreased the copies of L. intracellularis in rectal swabs containing feces and ileum infection (p < 0.001), reduced histopathological lesions in the ileum, and elicited non-specific humoral (IgG and sIgA) and cell-mediated immune responses (p < 0.001) compared with the challenge control and mock groups. Conclusions: In conclusion, the attenuated vaccine JS-G90 is safe and induced humoral and cell-mediated immune responses in pigs against pathogenic L. intracellularis infection. It may serve as an effective strategy for preventing and controlling PPE.

Assessing whether post mortem samples can provide value for monitoring during the post-weaning stages is necessary as this methodology can be adopted by the industry when resources are scarce. The objectives of this study are to assess pathogen detection in tongue tip fluids (TTFs), oronasal swabs (ONSs), rectal swabs (RSs), and superficial inguinal lymph nodes (SILNs). Two farms (one wean-to-finish farm and one finishing farm) undergoing a porcine reproductive and respiratory syndrome virus (PRRSV) outbreak were included, and 30 dead pigs were sampled during each farm visit. For PRRSV, the diagnostic accuracy of TTF, ONS, RS, and SILN were calculated using intracardiac serum as the gold standard. We also characterized the detection of PCV-2, PCV-3, PPV-1, PPV-2, Lawsonia intracellularis, and IAV in all collected specimens. Overall, TTF and SILN had the highest sensitivity for PRRSV-2 detection (95% and 99%, respectively). Most other pathogens were detected in TTF, with the highest detection rates were for PPV-2 (99%) and PCV-2 (41%). RS had mostly good detection rates for PPV-2 (27-73%), while ONS had similar detection rates (37%) to TTF (38%) for IAV. Altogether, this indicates that post mortem specimens can provide value for pathogen detection.

Background/Objectives: Lawsonia intracellularis is a bacterium that causes Proliferative Enteropathy, an enteric infection characterized mainly by diarrhea and growth retardation, leading to important economic losses. Acute and chronic infections are easily diagnosed, and their control by vaccination has been proven efficacious. However, subclinical infections, despite being very prevalent, often remain underdiagnosed and uncontrolled in practice. Scarce research is available on the control of subclinical infections by vaccination, and the benefit in these scenarios remains to be elucidated. Two field trials were carried out to (1) determine the association between the growth and fecal shedding of L. intracellularis in unvaccinated and intramuscularly vaccinated pigs in a farm with subclinical infection and (2) assess the impact of intradermal vaccination against L. intracellularis on clinical performance and carcass quality in a herd with subclinical infection. Methods: A pig herd with subclinical infection was selected. Pigs were vaccinated intramuscularly (study 1) or intradermally (study 2) at weaning. Fecal shedding, performance, clinical parameters, and carcass quality were investigated. Results: Growth was negatively associated with the fecal load of L. intracellularis in non-vaccinated pigs, whereas in vaccinated pigs, growth performance was not impacted by fecal load (study 1). Vaccinated pigs presented a significantly lower fecal load, lower prevalence of tail biting (31.7%) compared with controls (54.2%), less back fat, and a greater Lean Meat percentage (study 2). Conclusions: Vaccination against L. intracellularis in a herd with subclinical infection and low fecal bacterial shedding led to a reduction in fecal shedding, a lower prevalence of tail biting, and an improvement in carcass quality.

Lawsonia intracellularis is the causative agent of porcine proliferative enteropathy (PPE)—a disease of great economic impact to the global pig industry, but the isolation and continuous passage culture of this bacterial species is very difficult which limits the development of inactivated or live vaccines. While China is the largest pig rearing country in the world, only one study has reported the isolation of L. intracellularis. In this study, we examined 1574 ileal samples collected from 10 slaughterhouses in Hubei Province, China, and obtained 104 samples tested positive for L. intracellularis. From these positive samples, we successfully isolated a L. intracellularis strain designated LI-HuB23, which could be continuously passaged in IEC-18 cells. The successful isolation of LI-HuB23 was confirmed by transmission electron microscopy (TEM), indirect immunofluorescence assay (IFA), PCR amplifying, and Sanger sequencing of the marker gene (aspA). LI-HuB23 exhibited stable proliferation over 10 passages and it was still being passaged for over 30 generations. Oral inoculation of 28-day-old pigs with LI-HuB23 containing 6.9 × 108 bacterial microorganisms induced loose stools and watery diarrhea between Days 14 and 28 postinfection. Challenging pigs showed an average daily gain (ADG) lowered than the control pigs (206.05 ± 23.48 g/day vs. 241.43 ± 16.78 g/day). All challenging were serologically positive for L. intracellularis IgG at 21 days postinoculation. Histological examination detected crypt hyperplasia, characterized by a reduction in goblet cells within the hyperplastic crypts. Colonization of L. intracellularis in ileal crypts was confirmed by immunohistochemical examination.

Immunogenicity of a recombinant vaccine against Lawsonia intracellularis in mice

Background/Objectives: This study describes multiple trials demonstrating the safety and efficacy of a tri-valent vaccine against diseases caused by Porcine Circovirus Types 2a and 2d (PCV2a, PCV2d), Mycoplasma hyopneumoniae, and Lawsonia intracellularis. Methods: For each of the PCV2a and PCV2d onset of immunity (OOIs) and duration of immunity (DOI) studies, 25 pigs were vaccinated with a tri-valent vaccine and 25 with placebo. After dual challenge with PCV2a and porcine reproductive and respiratory virus (PRRSV) (OOI) or single challenge with PCV2d (OOI and DOI), respectively, viremia and lymphoid depletion data were collected. For each of the M. hyopneumoniae OOI and DOI studies, 35 to 70 pigs were vaccinated with the tri-valent vaccine and 35 to 70 with placebo. After M. hyopneumoniae challenge, the lungs were scored for disease. For the L. intracellularis OOI study, 40 to 50 pigs were vaccinated with the tri-valent and 40 to 50 with placebo. After L. intracellularis challenge, the intestines were scored for disease. All pigs were vaccinated at approximately 3 weeks of age, and all placebo vaccines were product matched. Results: Vaccinating pigs with a tri-valent vaccine reduced viremia and lymphoid depletion due to PCV2a and PCV2d, reduced lung lesions due to M. hyopneumoniae and reduced ileum and colonization scores due to L. intracellularis. Conclusions: The trials reported here demonstrated the safety and efficacy of the first ready-to-use PCV2, M. hyopneumoniae, and L. intracellularis vaccine for pigs.

Abstract In recent years, beta-glucans (BG) have gained increasing attention for their diverse health-promoting properties in both humans and animals. Yeast beta-glucans are polysaccharides known for their immunomodulatory effects, which have been extensively studied in various animal models. Especially when they are coming from yeasts, these polysaccharides exhibit the ability to train the innate immune system in particular monocytes and macrophages, enhancing phagocytosis, cytokine production, and overall immune response. In livestock production, such as swine, supplementation with yeast beta-glucans has demonstrated significant improvements in growth performance, feed efficiency, and disease resistance. Our studies from the lab to the field have demonstrated the improvement of health parameters leading to improved performances of pigs fed with yeast β-1,3/1,6 glucan up to 4kg by the end of the fattening period. Additionally, a reduction in the incidence of infections such as Lawsonia intracellularis by 53% was measured in the group of pigs receiving yeast β-1,3/1,6 glucan. These results showed that beta glucans offer a good alternative to reduce reliance on antibiotics, thus enhancing sustainability in animal agriculture. Yeast beta-glucans offer a promising avenue for enhancing animal health and disease prevention in livestock production systems. Their multifaceted benefits, including immunomodulation and positive impact on microbiota, make them valuable additives in animal feed formulations, contributing to sustainable and resilient agricultural practices.

Lawsonia intracellularis (LI), Brachyspira hyodysenteriae (Bhy), and Clostridium perfringens (Cp) are three common swine enteric pathogens widespread worldwide, leading to huge economic losses to the pig industry. LI, Bhy, and Cp are co-infected and should not be distinguished, and the detection of bacterial nucleic acids in feces allows rapid identification of whether a herd is infected with these three pathogens. In this study, we developed and optimized a TaqMan triple quantitative real-time PCR (qPCR) method for LI, Bhy, and Cp, which was validated and applied to the analysis of actual samples from pigs. This method was then applied to investigate 5,702 fecal swabs, environmental swabs, and ileum in China from 2021 to 2024. The results showed that the positive rates of the three pathogens were 9.54% (544/5,702; LI), 2.42% (138/5,702; Bhy), and 20.78% (1,185/5,702; Cp), respectively. In addition, mixed infections between some pathogens were also found.IMPORTANCEIn this study, we developed a triple real-time PCR method for the detection of Lawsonia intracellularis (LI), Brachyspira hyodysenteriae (Bhy), and Clostridium perfringens (Cp). A total of 5,702 samples from pig farms in China from 2021 to 2024 were detected by this method. The results showed that all three pathogens were detected and mixed infections occurred. This method is rapid, specific, and sensitive and can be used for the monitoring and rapid diagnosis of bacterial diarrhea in pig herds.

Porcine proliferative enteropathy (PPE) is an infectious disease in pigs, caused by Lawsonia intracellularis (LI), affecting their intestines during growth and finishing stages, leading to higher production costs. Current detection methods for LI face two main challenges, delayed results and high costs, making them impractical for large-scale pig farming epidemiological surveys. This study developed a TaqMan-qPCR method using specific probes and primers based on the LI aspartate ammonia lyase genes from GenBank, completing detection in just 45 min. After optimizing reaction conditions, sensitivity analysis revealed that the detection limit of this method was 4.6 copies/μL targeting standard plasmids. The results of the specificity analysis showed no cross-reactivity with other common porcine pathogens, highlighting its specificity. The inter- and intra-group coefficients of variation were both <1%, indicating high reproducibility. Furthermore, the TaqMan-qPCR demonstrated 100% relative sensitivity, and a 92.50% compliance rate compared to conventional PCR, suggesting it could be a complement to the conventional PCR method. In summary, the TaqMan-qPCR method established in this study is not only suitable for epidemiological investigations and early qualitative and quantitative diagnosis of proliferative enteropathy in pigs, but it is also valuable for studying the biological characteristics of LI.

Background and Aim:Lawsonia intracellularis is an obligatory intracellular bacterium associated with equine proliferative enteropathy (EPE), which significantly impacts equine health. Despite its clinical relevance, epidemiological and diagnostic approaches for this infection in horses have remained underexplored. This study aimed to evaluate the humoral immune response in horses immunized with an experimental vaccine for L. intracellularis and to determine the occurrence of anti-L. intracellularis antibodies in horses from southern Brazil using the flow cytometry antibody test (FCAT).Materials and Methods:A total of 12 horses were immunized with an experimental vaccine containing inactivated L. intracellularis and adjuvants. Blood samples were collected on day 0 (D0) and every 7 days until day 35 (D35) to monitor the antibody response using FCAT. In addition, serum samples from 79 horses from the North and Northwest regions of Rio Grande do Sul were tested to determine the occurrence of anti-L. intracellularis antibodies. The FCAT protocol was optimized for equine samples, and a cut-off fluorescence threshold was determined using Receiver Operating Characteristic curve analysis.Results:FCAT demonstrated high accuracy, with a sensitivity of 100% and specificity of 92% at a fluorescence cut-off of ≥15%. Immunization triggered a robust humoral response, with a significant increase in fluorescence from day 7 to day 35. In the occurrence analysis, 26% of the horses tested positive for anti-L. intracellularis antibodies. The highest occurrence was observed in females (35.8%) and horses aged 16–22 years (50%).Conclusion:This study provided evidence that L. intracellularis infection is relatively common among horses in southern Brazil. FCAT was a sensitive and specific diagnostic tool for detecting anti-L. intracellularis antibodies in horses. The findings highlight the need for better diagnostic and preventive measures to control EPE in equine populations.

The combined, intradermal application of multiple vaccines against key diseases in swine offers many benefits, including reduced time and labor costs, and improved animal welfare due to fewer injections and manipulations. This study investigated the efficacy of a newly developed intradermal combination vaccine for Porcine circovirus 2 (PCV2) and Mycoplasma hyopneumoniae (M hyo) (PCV M Hyo ID vaccine) in swine. The vaccine was evaluated for its efficacy against PCV2 and M hyo infection and its concurrent mixed use with Lawsonia intracellularis (LI) and non-mixed use with Porcine reproductive and respiratory syndrome virus (PRRSV) vaccines. The findings demonstrated that the PCV M Hyo ID combination vaccine is efficacious against PCV2 and M hyo infection. Furthermore, the new PCV M Hyo ID combination vaccine can also be administered simultaneously and at the same anatomical location after mixing with LI ID vaccine, and next to PRRS ID vaccine, to efficiently protect pigs from all four major diseases in swine. The efficacy with the combination of vaccines was equivalent to that of the single vaccines.

Lawsonia intracellularis (LI) are obligate intracellular bacteria and the causative agent of proliferative hemorrhagic enteropathy that significantly impacts the health of piglets and the profitability of the swine industry. In this study, we used immunoinformatic and computational methodologies such as homology modelling, molecular docking, molecular dynamic (MD) simulation, and free energy calculations in a novel three stage approach to identify strong T and B cell epitopes in the LI proteome. From ∼ 1342 LI proteins, we narrowed our focus to 256 proteins that were either not well-identified (unknown role) or were expressed at a higher frequency in pathogenic strains relative to non-pathogenic strains. At stage 1, these proteins were analyzed for predicted virulence, antigenicity, solubility, and probability of residing within a membrane. At stage 2, we used NetMHCPan4-1 to identify over ten thousand cytotoxic T lymphocyte epitopes (CTLEs) and 286 CTLEs were ranked as having high predicted binding affinity for the SLA-1 and SLA-2 complexes. At stage 3, we used homology modeling to predict the structures of the top ranked CTLEs and we subjected each of them to molecular docking analysis with SLA-1*0401 and SLA-2*0402. The top ranked 25 SLA-CTLE complexes were selected to be an input for subsequent MD simulations to fully investigate the atomic-level dynamics of proteins under the natural thermal fluctuation of water and thus potentially provide deep insight into the CTLE-SLA interaction. We also performed free energy evaluation by Molecular Mechanics/Poisson-Boltzmann Surface Area to predict epitope interactions and binding affinities to the SLA-1 and SLA-2. We identified the top five CTLEs having the strongest binding energy to the indicated SLAs (-305.6 kJ/mol, -219.5 kJ/mol, -214.8 kJ/mol, -139.5 kJ/mol and -92.6 kJ/mol, respectively.) W also performed B-cell epitope prediction and the top-ranked 5 CTLEs and 3 B-cell epitopes were organized into a multi-epitope subunit antigen vaccine construct joined using EAAAK, AAY, KK, and GGGGG linkers with 40 residues of the LI DnaK protein attached to the N-terminus to further enhance the antigenicity of the vaccine construct. Blind docking studies showed strong interactions between our vaccine construct with swine Toll-like receptor 5. Collectively, these molecular modeling and immunoinformatic analyses present a useful in silico protocol for the discovery of candidate antigen in many viral and bacterial pathogens.

This study evaluated vaccination and prophylactic use of antimicrobials as strategies to prevent Porcine Proliferative Enteropathy (PPE) during nursery and growth-finishing phases. Three hundred weaned piglets (~ 29 days old) were distributed into groups: NVMED - no vaccinated against Lawsonia intracellularis but in-feed medicated with antimicrobials (amoxicillin, florfenicol, lincomycin, spectinomycin and tilmicosin); VMED - vaccinated and in-feed medicated; VNMED - vaccinated but no in-feed medicated. Piglets were vaccinated at weaning (Porcilis® Ileitis, MSD Animal Health). The following variables were assessed: growth and health performance, anti-L. intracellularis IgG levels, L. intracellularis fecal shedding, Pneumonia and Pleurisy Index (PPI) at slaughter, antimicrobial consumption and costs, and vaccination expenses. Average daily gain (ADG) at the nursery phase was lower in VNMED group (p < 0.01); however, there was no treatment effect on feed conversion, ADG, and body weight at growth-finishing phase (p ≥ 0.23). Similar anti-L. intracellularis IgG levels were found for VMED and VNMED groups at all evaluated moments (p = 0.01). L. intracellularis was only detected in feces samples from 4/90 tested piglets and no difference in health performance was found (p > 0.05). Groups presented PPI < 0.89. In-feed antimicrobial consumption and related costs were 3 to 3.5-fold higher for NVMED and VMED groups compared to VNMED group. The prophylactic administration of antimicrobials used in this study did not affect the serological performance post-vaccination against L. intracellularis. Additionally, vaccine use to prevent PPE reduced the antimicrobial consumption and related costs by ~70%, with no impairments on production outputs.

Lawsonia intracellularis and Brachyspira species are important enteric pathogens in commercial pig farming. Despite their importance, there is little information on the epidemiology and risk factors of these pathogens in Vietnam. Therefore, this study investigated the percentage of L. intracellularis, B. pilosicoli, and B. hyodysenteriae across 18 commercial pig farms in Vietnam and analyzed risk factors for L. intracellularis infection. Fecal samples were collected from pigs in three age groups, and bacterial DNA was analyzed using quantitative PCR. The study found a 100% percentage of L. intracellularis at the farm level, with 90.74% of individual samples testing positive. B. pilosicoli was detected in 27.78% of farms, while B. hyodysenteriae was not detected in any samples. Risk factor analysis revealed thatpost weaning diarrhea, direct contact between pig batches, and the presence of rats were significantly associated with L. intracellularis infection. Post-weaning frequently experience diarrhea had a 1.8 times higher risk than non-diarrhea, and direct contact between pigs increased infection risk by 10.29 times. The presence of rats also contributed to higher infection rates. These findings emphasize the importance of improved biosecurity, and effective management practices to control the spread of L. intracellularis in Vietnamese pig farms.

Lawsonia intracellularis (LI) is the agent of proliferative enteropathy in swine, a common disease that affects pigs for up to eight weeks after weaning. To evaluate the effectiveness of two novel subunit vaccines targeting outer membrane proteins on LI. The two vaccines included OMP2c.cVLP, where the OMP2c antigen was anchored on the surface of capsid virus-like particles (cVLP); and MBP.INVASc, where antigens were anchored to an MBP fusion protein. Groups of six mice, as proof of concept, and six piglets were immunized with either OMP2c.cVLP, MBP.INVASc., or PBS as a control using a prime-boost regime. Both OMP2c.cVLP and MBP.INVASc subunit vaccines induced strong antigen-specific serum IgG and IgA responses. There were no significant differences in weight gain among the groups. Mild-to-moderate clinical signs of LI infection were observed, but vaccinated groups showed lower inflammatory scores and fewer animals tested positive for bacteria by immunohistochemistry. Although neither vaccine completely prevented clinical signs of LI infection, both effectively reduced inflammation and lowered the pathogen load, thereby mitigating the severity of the disease, particularly the MBP.INVASc vaccine. These findings suggest that both vaccines have the potential for further development and optimization to enhance their protective efficacy against LI infections.

Lawsonia intracellularis, a Gram-negative obligate intracellular bacterium causing porcine proliferative enteropathy, possesses a type III secretion system (T3SS), yet only a handful of its substrates have been experimentally characterized. In this study, we identify that LI0758 can be secreted by the Yersinia T3SS, which suppresses yeast growth and activates mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathway in mammalian cells. Bioinformatics analyses indicate that LI0758 is an ortholog of Rce1, a eukaryotic CAAX protein endoprotease, sharing a similar subcellular localization on the endoplasmic reticulum (ER). While displaying unique activity in the yeast a-factor reporter system, LI0758 restores Ras2 localization in Rce1Δ mutant strains, implying functional similarity. Our findings underscore LI0758’s pivotal role in activating MAPK pathways and suggest its potential to modulate the localization and function of host CAAX proteins. Further investigation holds promise for elucidating novel bacteria-host interaction mechanisms and fostering the development of innovative therapies against proliferative enteritis.

Effective disease management strategies are essential for achieving optimal pig performance, ensuring high-quality animal health and welfare, and maintaining the economic viability of swine systems. Thus, understanding factors that lead to more or less severe disease are critically important. Porcine circovirus type 2 (PCV2) and Lawsonia intracellularis (L. intracellularis) are endemic pathogens in the U.S., affecting herds with varying degrees of subclinical and clinical disease and impact on performance. While these are common pathogens, their interaction with PRRSV and performance has seldom been investigated. This study investigated the detection dynamics of L. intracellularis, PRRSV, and PCV2, and their association with productivity impacts in wean-to-finish groups within a Midwest U.S. production system. This observational field study involved batches of growing pigs from PRRSV-stable or PRRSV-negative sow farms. Oral fluids were collected longitudinally from weaning until market age, and tested using quantitative PCR for each of the aforementioned pathogens. The study included 36 batches with a total of 46,446 growing pigs, resulting in 4,000 oral fluid samples. Then, batches were categorized based on key performance indicators (mortality and average daily gain), PRRSV detection timing and total genomic copies of each pathogen. Nineteen groups were characterized as high-performance and seventeen as low-performance. Mortality ranged from 5 to 9% in high-performance groups and 10.3-20.9% in low-performance groups. Average daily gain ranged from 0.68-0.86 kg in high-performance groups and 0.63-0.81 kg in low-performance groups. L. intracellularis and PCV2 were detected in most groups, with significant differences in detection rates between high and low-performance groups. Groups with relatively high genomic copies of PCV2 and L. intracellularis that had PRRSV detection presented higher mortality rates (15.75%). This study expanded our understanding of PRRSV, PCV2, and L. intracellularis co-detections and their impact on swine populations.