Search Results (40)

Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), poses a serious threat to the global swine industry. Although modified live virus (MLV) vaccines have been widely used in the field for PRRS prevention for decades, the safety and efficacy of these vaccines have long been controversial. Here, we report a rare recombination pattern in China: the emergence of a novel NADC30-like PRRSV strain recombined from two MLV-like strains. Genome comparative analysis reveals that the SCMS2025 isolate has a non-continuous 136-amino acid deletion in the NSP2 protein and shares the highest nucleotide identity of 87.6% with lineage 5 (L5) strains. Phylogenetic analysis showed that SCMS2025 was classified into L1 (NADC30-like) strains based on ORF5 genotyping, whereas it belonged to a single branch between L1 and L5 strains based on the complete genomic sequences. Strikingly, genomic recombination analysis revealed that the newly emerged PRRSV isolate likely resulted from complex recombination events between NADC30-like and two MLV-like strains (RespPRRS MLV and TJbd14-1 MLV-like strains). Furthermore, SCMS2025 infection caused transient overt clinical signs followed by rapid recovery, indicating that the novel PRRSV isolate is a low pathogenic strain. Notably, all SCMS2025-inoculated piglets remained seronegative for PRRSV-specific antibodies throughout the entire 14-day observation period, suggesting a delayed onset of the host humoral immune response. Our study provides evidence for the ongoing evolution of PRRSV through inter lineage recombination and highlights the urgent need for safe and effective vaccines. Full article

Porcine reproductive and respiratory syndrome virus genotype 1 (PRRSV-1), particularly the BJEU06-1-like subgroup, has shown increasing detection in China; however, the biological characteristics of newly emerging strains in southwestern regions remain insufficiently defined. Therefore, this study aimed to isolate and characterize a PRRSV-1 strain circulating in Southwestern China and to compare its biological properties and pathogenicity with those of a representative NADC30-like PRRSV-2 strain. In this study, a PRRSV-1 field strain (CDAC-SC2025) was isolated from a lung sample collected in Sichuan Province and characterized by immunofluorescence, full-genome sequencing, and maximum-likelihood phylogenetic analysis. Recombination was assessed using RDP4 and SimPlot (Baltimore, MD, USA). Pathogenicity was evaluated in newborn piglets following intranasal challenge, with monitoring of clinical signs, viremia, viral shedding, tissue viral loads, and histopathology. CDAC-SC2025 clustered within the BJEU06-1-like subgroup and showed the closest relationship to HENZMD-10 without detectable recombination. A three-amino-acid deletion (373–375 aa) was identified in nsp2. In vivo, CDAC-SC2025 induced fever, respiratory signs, growth retardation, and mortality, but the onset of death was delayed and lesion severity was lower than those caused by the NADC30-like strain DJY. Both strains exhibited predominant viral loads in the lung and tonsils, although quantitative differences were observed across tissues. Histopathology revealed moderate lesions in CDAC-SC2025-infected piglets compared with more severe multisystemic damage caused by DJY. These findings provide updated data on the biological properties of BJEU06-1-like PRRSV-1 circulating in southwestern China. Full article

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) poses a serious threat to the swine industry in China. As a major pig-producing province, Shandong requires continuous epidemiological monitoring of PRRSV. To elucidate the molecular epidemiology of the virus, 1621 clinical samples were collected from suspected cases across different regions of Shandong Province between 2023 and 2025, primarily from Tai’an, Linyi, Jining, and Liaocheng. RT-qPCR detection showed that the positive rate for PRRSV-2 was 20.05% (325/1621). Genetic analysis based on ORF5 and NSP2 genes indicated that Sublineage L1C (NADC30-like) was the dominant strain for 38.38% of ORF5 gene and 72.73% of NSP2 sequencing results. This was followed by Sublineage L8E and L1A and L5A strains. Key virulence-related mutations were identified at residues R13 and R151 in the GP5 protein, which are associated with enhanced pathogenicity. Additionally, variations in neutralizing epitope and the number of N-glycosylation sites (ranging from 2 to 5 per strain) suggested potential immune evasion. Notably, 26.79% (15/56) of sequenced samples showed discordant ORF5 and NSP2 genotyping results, indicating widespread recombination among PRRSV strains in Shandong Province. These finding demonstrated that the genetic diversity, high recombination frequency, and key amino acid variations in circulating PRRSV strains collectively undermine vaccine effectiveness. This study highlights the need to optimize vaccination strategies, enhance biosecurity measures, and implement effective disease control and elimination programs to reduce the impact of PRRSV in Shandong Province. Full article

Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major cause of economic loss in the swine industry, and highly pathogenic variants such as NADC34-like PRRSV highlight the need for antiviral strategies that complement vaccination. In this field study, we evaluated the efficacy of AlimenWOW, a rottlerin–lipid formulation, in grower–finisher pigs under commercial conditions using AI-based respiratory monitoring. A total of 2000 pigs were assigned to four groups: AlimenWOW G1 (PRRSV-stable source farm), AlimenWOW G2 (PRRSV-unstable source farm), Control 1 (antibiotic), and Control 2 (antipyretic). Respiratory Health Status (ReHS) and a derived Clinical Cough Index (CCI = 100 − ReHS) were continuously recorded with SoundTalks^®, and oral fluid PRRSV load, serology, clinical outcomes, and productivity were assessed over 4 weeks. AlimenWOW G2 showed a marked improvement in ReHS from severely compromised baseline values to levels comparable with healthy status, while both control groups remained low; CCI was significantly lower in AlimenWOW G2 than in controls from day 14 onward (p ≤ 0.0001). AlimenWOW treatment was associated with reduced PRRSV titers in oral fluid, lower mortality and wasting rates, and improved feed conversion with lower feed costs compared with controls. These findings indicate that AlimenWOW, integrated with AI-based acoustic monitoring, can improve respiratory health and mitigate PRRSV-associated clinical and economic losses, supporting its use as a complementary tool in PRRSV control programs. Full article

PRRSV poses a persistent global challenge to the swine industry due to its rapid evolution. This study aimed to characterize a novel PRRSV2 strain, HeB2023092, isolated from a suspected outbreak in China in September 2023. We performed virus isolation in porcine alveolar macrophages (PAMs), genome sequencing, phylogenetic analysis, and comprehensive genetic characterization. HeB2023092 replicated effectively in PAMs but not in Marc-145 cells. Phylogenetic analysis consistently grouped it with NADC30-like strains (L1.8). Notably, genomic analysis revealed a unique 41-amino acid deletion (478–518 aa) in Nsp2, in addition to the characteristic 111-amino acid deletion of NADC30-like strains. Significant amino acid variations were also found in the antigenic epitopes and N-glycosylation patterns of GP3 and GP5. Comprehensive recombination analysis identified three distinct recombinant regions, revealing a mosaic genome with a predominant NADC30-like backbone. The backbone incorporated genetic sequences from JXA1-like (L8.7) strains in two regions and from NADC34-like (L1.5) strains in one region. These findings highlight the continuous genetic evolution and complex epidemiology of PRRSV, underscoring the critical need for sustained surveillance and detailed characterization of circulating strains to inform effective control and vaccine development strategies. Full article

Porcine reproductive and respiratory syndrome virus (PRRSV), a major pathogen causing substantial economic losses in the global swine industry, was studied in southern Xinjiang to characterize its local epidemic features. Based on 632 clinical samples collected from 13 pig farms between 2023 and 2025, quantitative RT-PCR detection showed an overall positivity rate of 18.35% (116/632), with PRRSV-2 single infection accounting for 97.41% (113/116), PRRSV-1 single infection for 1.72% (2/116), and co-infection for 0.86% (1/116). Among 38 ORF5 sequences obtained from positive samples, Sublineage 1.8 (NADC30-like) was dominant, comprising 97.14% of successfully sequenced strains. Molecular analysis revealed that PRRSV-1 isolates carried six amino acid mutations including A129V (consistent with the Chinese strain CN/FJFQ-1/2023), while PRRSV-2 strains exhibited key variations such as the neutralization escape mutation Q13R, virulence-associated site K151R, and an anomalous vaccine marker A137. Furthermore, a recombinant strain (XJLETUQ2025-7) between NADC30 and VR-2332 was identified with breakpoints in NSP2 and NSP10. Serological surveillance of 2043 vaccinated pigs showed an overall antibody positive rate of 83.0% (1696/2043), with increasing annual rates from 72.3% (2023) and 75.4% (2024) to 91.3% (2025). In conclusion, the PRRSV epidemic in southern Xinjiang is primarily driven by NADC30-like strains of PRRSV-2, with recombination events and GP5 epitope variations posing challenges to disease control. These findings enhance the epidemiological understanding of PRRSV in the region and provide valuable insights for vaccine development and prevention strategies. Full article

Background: With a high human immunodeficiency virus (HIV) adult prevalence, people living with HIV (PLHIV) in Botswana continue to experience a high burden of comorbid HIV and cancer. We sought to investigate the trends of acquired immunodeficiency syndrome (AIDS) defining cancers (ADCs), non-AIDS defining cancers (NADCs), and associated risk factors in PLHIV compared with those without HIV. Methods: We analyzed data from adults aged ≥18 years reported in Botswana National Cancer Registry and National Data Warehouse. The crude, age-standardized incidence rate (ASIR), standardized incidence ratios (SIRs) of cancers and time trends were computed. Risk factors were determined using the Cox-regression model. Results: Over a 30-year period, 27,726 cases of cancer were documented. Of these, 13,737 (49.5%) were PLHIV and 3505 (12.6%) were people without HIV and 10,484 (37.8%) had an unknown HIV status. Compared to the HIV-uninfected, the PLHIV had higher and increasing trends in the cancer incidence overall during the study period (from 44.2 to 1047.6 per 100,000; p-trend < 0.001) versus (from 1.4 to 27.2 per 100,000; p-trend < 0.001). The ASIRs also increased in PLHIV for overall ADCs, NADCs and other sub-types like cervical, lung, breast, and conjunctiva cancers (p-trend < 0.001). Further, PLHIV had elevated SIRs for cervical cancer, Kaposi sarcoma in males and some NADCs. The most common risk factors were HIV infection and female sex for ADCs incidence and advanced age and being HIV-uninfected for NADCs incidence. Conclusions: Increasing trends of ADCs and NADCs during ART expansion were observed among PLHIV compared to those without HIV highlighting a greater need for targeted effective prevention and screening strategies including the provision of access to timely HIV and cancer treatment. Full article

The global pork production sector continues to experience substantial financial burdens attributable to porcine reproductive and respiratory syndrome virus (PRRSV) infections. Despite the current epidemiological landscape in which NADC30-like strains predominate alongside cocirculating diverse PRRSV subtypes, highly pathogenic PRRSV (HP-PRRSV) remains a persistent threat. Furthermore, currently available commercial PRRS vaccine formulations exhibit restricted heterologous protection efficacy. The development of novel mRNA-based vaccines represents a promising strategy for PRRS mitigation protocols. In response to these epidemiological challenges, an HP-PRRSV strain (Lineage 8), designated as JX021, was isolated and characterized in this study. Pathogenicity experiments confirmed that JX021 induces severe clinical symptoms in piglets. Moreover, by combining immunoinformatics and literature-guided approaches, critical antigenic epitopes on HP-PRRSV (represented by the JXA1 strain) structural proteins were identified, enabling the design and synthesis of a multiepitope mRNA vaccine. The survival of piglets immunized with the mRNA vaccine was higher than that of the inactivated vaccine immunization group and the PBS group. Compared with the inactivated vaccine group, the mRNA vaccine group presented reductions in viremia and lung lesions. These findings provide new insights into the design and development of further PRRS vaccine research. Full article

Porcine reproductive and respiratory syndrome virus (PRRSV) poses a significant economic challenge to Japan’s swine industry. This review synthesizes the epidemiological evolution of PRRSV in Japan by examining the available scientific literature from its initial Type 2 isolation in 1993 to recent events. Endemic Type 2 strains, initially dominated by Cluster III (Lineage 4), have diversified significantly. This diversification was marked by key events including the emergence of vaccine-associated Cluster II (Lineage 5) and incursions of virulent Cluster IV/Lineage 1F (MN184A-like) strains and Type 1 virus around 2008. By 2018–2020, Clusters II and IV predominated nationwide, a trend strongly linked to widespread modified live virus (MLV) vaccination. The recent detection of the globally significant NADC34-like (Lineage 1A) strain underscores ongoing foreign incursion risks. Current MLV vaccines face challenges, including safety concerns and limited cross-protection against diverse field strains. Consequently, effective control requires integrated strategies, comprising optimized vaccination, stringent biosecurity, advanced molecular surveillance, improved diagnostics, and coordinated regional control programs guided by systematic herd classification and stakeholder partnerships. The development of next-generation vaccines and sustained multi-stakeholder collaboration are critical for mitigating the impact of PRRSV in Japan. Full article

Due to its high genomic variability, the epidemiological landscape of porcine reproductive and respiratory syndrome virus (PRRSV) has become increasingly complex in recent years. From 2022 to 2023, we collected a total of 1044 clinical samples from pigs suspected of PRRSV infection in China and discovered a PRRSV-positive rate of 29.8% (311/1044) using RT-PCR targeting the nsp2 gene. Among these positive samples, NADC30/34-like PRRSV, highly pathogenic PRRSV (HP-PRRSV), and classical PRRSV strains accounted for 60.1%, 37.9%, and 4.5%, respectively. These results indicate that the most prevalent PRRSV strains in China are NADC30/34-like PRRSV, followed by HP-PRRSV. Two PRRSV strains, JX03 and HN08, were isolated, and TCID₅₀ assays were performed to determine their titers at different time points post-infection, revealing differences in their proliferation kinetics. Phylogenetic, amino acid sequence, and recombination analyses demonstrated that the JX03 and HN08 strains cluster within lineage 8 (HP-PRRSV) and sublineage 1.5 (NADC34-like PRRSV), respectively. Notably, the HN08 strain was identified as a recombinant between the NADC30-like and NADC34-like strains, while no recombination event was detected in the JX03 strain. Pathogenicity assessments showed that the JX03 strain exhibited higher pathogenicity than the CHN-HB-2018 strain (a NADC30-like PRRSV strain was previously isolated by our lab), as evidenced by differences in clinical signs and mortality rates in piglets. In contrast, HN08 displayed no obvious clinical symptoms or mortality, revealing lower pathogenicity than the CHN-HB-2018 strain. These findings provide valuable information on the epidemiological and genetic characteristics of PRRSV strains in China, laying a foundation for the development of effective strategies against PRRSV. Full article

First reported in 1987, the porcine reproductive and respiratory syndrome virus (PRRSV) has significantly disrupted the major regions affected by PRRSV in the pig breeding industry. Recently, outbreaks of disease caused by recombinant PRRSV strains in China have raised serious concerns. Effective immunization and infection control in pig populations is critical, as the virus frequently undergoes mutation and recombination. This study characterized a novel recombinant PRRSV strain, BX/CH/22, isolated from Northeast China. Genetic analysis revealed that BX/CH/22 is a recombinant of JXA1, NADC 30-like, and NADC 34-like strains. Phylogenetic analysis of the non-structural protein (NSP) 2 region classified BX/CH/22 as JXA1 PRRSV-like, with a characteristic deletion of 30 discontinuous amino acids in NSP2. However, Open Reading Frame (ORF) 5 analysis classified it as NADC 30-like PPRSV, while whole-genome phylogenetic analysis classified it as NADC 34-like PPRSV. Recombination analysis revealed that BX/CH/22 contains an NADC 34-like PRRSV backbone, an NSP-coding region from NADC 30-like PRRSV, and an ORF2-ORF6 region from NADC 34-like PRRSV. The strain was isolated from serum samples obtained from commercial swine farms undergoing active PRRS outbreaks. In animal experiments, all BX/CH/22-challenged piglets exhibited persistent fever, with peak temperatures >40.5 °C at 4–9 dpi resolving by 11 dpi, accompanied by cough, anorexia, and lethargy. A significant reduction in daily weight gain was observed in infected groups compared to asymptomatic controls, with a 100% survival rate. Our findings provide early warning for PRRSV immune control strategies. Full article

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is one of the most significant infectious agents threatening the global pig industry. Due to its high mutation and recombination rates, the prevalence of PRRSV in domestic pig populations is complex. To better understand the epidemiology of PRRSV, we conducted a large-scale investigation in eastern China, focusing on pig farms with a history of high abortion rates. A total of 14,934 pig samples were collected from 11 sow farms and 53 fattening farms across three provinces. Among these, 13.0% of the collected samples tested positive for PRRSV, with specific prevalence rates of 19.7% in sows and 12.4% in piglets. Genetic evolution analysis of the GP5 gene from 43 PRRSV strains identified in this study revealed that NADC30-like, NADC34-like, and HP-PRRSV were the predominant lineages in domestic pig farms. The NADC30-like genotype was the most dominant and had evolved into three subgenotypes, while the NADC34-like strains had diverged into two subgenotypes. Further analysis of the Nsp2 gene from 18 strains indicated that the NSP2 gene of multiple NADC34-like strains was closely related to that of the NADC30-like, suggesting that the NADC34-like strains are primarily recombinant viruses. Sequence comparison of the Nsp2 gene showed that both NADC30-like and NADC34-like viruses share 111 amino acid deletions at positions 322–433 and 21 amino acid deletions at positions 539–558 in the Nsp2 gene coding region. For the first time, the pathogenicity of a representative NADC34-like virus isolated in China was evaluated in pregnant sow. The results showed that infected sows exhibited an increased body temperature, ear cyanosis, and typical edema and cyanosis of the external genitalia. Moreover, all infected sows experienced miscarriage, with 100% of the aborted piglets being stillbirths exhibiting a high virus load. These findings indicate that this NADC34-like virus is highly virulent to sows. Full article

NADC34-like porcine reproductive and respiratory syndrome virus (PRRSV) has been circulating in China for several years, causing substantial economic losses to the local pig industry. Current commercial vaccines have failed to provide complete protection against NADC34-like PRRSV infection. Additionally, the poor adaptation of NADC34-like strains to Marc-145 cells presents a considerable challenge for developing effective vaccines against these strains. This study addresses these challenges by developing a novel vaccine candidate against NADC34-like PRRSV. We engineered a recombinant PRRSV, rNADC34-CHSps, by replacing the structural protein region of the JS2021NADC34 strain with that of the CHR6 strain to improve its adaptation to Marc-145 cells. The rescued strain could proliferate well in Marc-145 cells, maintaining high titers and stable growth kinetics even at high passage numbers. Piglets were vaccinated with rNADC34-CHSps at passage 80 and then challenged with the virulent NADC34-like PRRSV strain, JS2021NADC34, at 28 days post-vaccination. All vaccinated piglets developed specific antibodies against PRRSV at 14 dpv and showed no significant clinical symptoms, even after exposure to PRRSV JS2021NADC34. Furthermore, the vaccinated piglets gained significantly more weight, displayed much less severe pathological lesions, and reduced viremia compared to the challenge control piglets. These results indicate that rNADC34-CHSps is a promising vaccine candidate against NADC34-like PRRSV infection, highlighting the potential of targeted genomic modifications to enhance vaccine efficacy. Full article

Porcine reproductive and respiratory syndrome (PRRS) is a pig respiratory disease threating the global swine industry. To combat PRRS, it is necessary of the effective diagnostic detection of antibody, including developing a neutralizing antibody against porcine reproductive and respiratory syndrome virus (PRRSV), especially the currently prevalent NADC30-like PRRSV in China. In this study, we prepared three monoclonal antibodies (mAbs) against NADC30-like PRRSV glycoprotein 5 (GP5) protein, and identified two corresponding precise epitopes (¹⁵⁵WR¹⁵⁶ and ¹⁹⁶QWGRP²⁰⁰). In the neutralization test, ¹⁹⁶QWGRP²⁰⁰ recognizing GP5 mAbs (11E6 and 12D1) exhibited obvious neutralizing activity, whereas the ¹⁵⁵WR¹⁵⁶ recognizing mAb (3A8) showed low neutralizing activity. Based on the two antigenic peptides, a peptide-based Enzyme-Linked Immunosorbent Assay (ELISA) was developed to detect antibodies against PRRSV, presenting high specificity, sensitivity, and repeatability. The concordance rate of the peptide-based ELISA and commercial IDEXX PRRSV X3 Ab ELISA in detection of 81 clinical samples was 82.7%. In conclusion, the GP5 peptide-based ELISA can be used for the detection of neutralizing antibodies against NADC30-like PRRSV, providing a rapid and reliable method for monitoring PRRSV infection. Full article

The porcine reproductive and respiratory syndrome virus (PRRSV) possesses an inherent ability to adapt to environmental transformations and undergo evolutionary changes, which has imposed significant economic pressure on the global pig industry. Given the potential for recombination among PRRSV genomes and variations in pathogenicity, newly emerging PRRSV isolates are of considerable clinical importance. In this study, we successfully isolated a novel strain named XJ-Z5 from PRRSV-positive samples collected in Xinjiang province in 2022. Through comprehensive genomic sequencing, phylogenetic analysis, and recombination analysis, we confirmed that this strain belongs to the NADC30-like recombinant PRRSV. During pathogenicity tests in piglets, this strain exhibited moderate virulence, causing symptoms such as reduced appetite, persistent fever, and weight loss; however, no mortality cases were observed. Tests conducted at various time points detected the presence of PRRSV nucleic acid in nasal swabs, rectal swabs, tissue samples, and blood, with the highest viral loads found in lung tissue and blood. Serum biochemical tests indicated significant impairment of liver and kidney function. PRRSV antibodies began to appear gradually after 10 days post infection. Hematoxylin and eosin staining revealed substantial pathological changes in lung tissue and lymph nodes. This study enhances our understanding of the epidemiology of PRRSV and underscores the importance of ongoing monitoring and research in light of the challenges posed by the continuous evolution of viral strains. Furthermore, the research emphasizes the urgency of the rapid genomic analysis of emerging viral strains. Through these comprehensive research and monitoring strategies, we aimed to curb the spread of PRRSV more effectively and thus reduce the huge economic losses it caused to the pig industry. Full article