Detection and genetic evolution analysis of porcine parvovirus type 7 (PPV7) in Fujian Province.

Porcine parvovirus (PPV) is an important pathogen causing reproductive disorders in sows, with clinical symptoms including stillbirth, mummified fetuses, embryonic dysplasia and death, and sow infertility. Porcine parvovirus 7 (PPV7) is a recently discovered type of PPV and its widespread distribution and rapid evolution has caused huge economic losses in the pig industry. To investigate the molecular epidemiology of PPV7 in Fujian Province, China, we collected 491 blood samples and 72 tissue samples from diseased pigs in large-scale pig farms across selected areas of Fujian Province from 2019 to 2022. PPV7 infection was determined using real-time quantitative PCR, and positive samples underwent whole-genome amplification, sequencing, and subsequent homology, phylogenetic, and recombination analyses. The PPV7 positive detection rate was 25.73% (145/563) in Fujian Province, among which the positive rate of blood and tissue samples was 26.47% (130/491) and 20.83% (15/72), respectively. The nucleotide sequence homology among the 29 PPV7 whole-genome sequences obtained in this study was 90.0%-97.2%, whereas that with 128 reference strains from China and other countries was 88.9%-98.1%. Six strains had partial nucleotide deletions or insertions. Phylogenetic analysis based on the whole-genome sequences classified the 29 PPV7 strains and 128 reference strains into eight subtypes (PPV7a-PPV7h), and PPV7h was the predominant subtype in Fujian Province. Recombination analysis revealed evidence of inferred recombination events in the genomes of four strains. This study provides significant insights into the molecular characteristics of PPV7 in Fujian Province and serves as a crucial foundation for further advancements in PPV7 prevention and control strategies.

Molecular Characteristics and Pathogenicity of a Novel Recombinant Porcine Reproductive and Respiratory Syndrome Virus Strain from NADC30-, NADC34-, and JXA1-Like Strains That Emerged in China.

Recently, the emergence of a NADC34-like porcine reproductive and respiratory syndrome virus (PRRSV), which causes a large number of abortions in swine herds, has raised great concern in China. In this study, a PRRSV variant strain, PRRSV/CN/FJGD01/2021, evolved from recombination between NADC30-like, NADC34-like, and JXA1-like viruses was isolated in Fujian province in 2021, and its pathogenicity in piglets was examined. Animal experiments demonstrated that PRRSV/CN/FJGD01/2021 infection could induce 100% morbidity and cause higher viremia, a persistently higher fever (>40°C for 14 consecutive days), significant weight loss, and severe histopathological lung lesions compared to the NADC30-like FJZ03 strain and NADC34-like FJ0908 strain in piglets. The PRRSV/CN/FJGD01/2021 strain displayed higher pathogenicity than the FJZ03 and FJ0908 strains, but lower pathogenicity than the Chinese highly pathogenic (HP)-PRRSVs in piglets. Moreover, the Ingelvac PRRS modified live vaccine (MLV) provides incomplete cross-protection against heterologous PRRSV/CN/FJGD01/2021 in piglets. Our findings contribute to the understanding of the current epidemic situation of NADC34-like PRRSV in China. IMPORTANCE The pathogenicity of NADC34-like PRRSV has broad variations in virulence. Importantly, NADC34-like PRRSV has undergone complex recombination with local strains since it first emerged in 2017 in China. However, the pathogenicity of the recombinant NADC34-like virus was rarely experimentally evaluated in pigs. In this study, a novel PRRSV strain, PRRSV/CN/FJGD01/2021, was isolated from sows enduring a high-abortion-rate (20%) period in China in 2021. Notably, phylogenetic and recombination analyses revealed that PRRSV/CN/FJGD01/2021 is a recombinant virus from NADC30-, NADC34-, and JXA1-like isolates. PRRSV/CN/FJGD01/2021 was shown to cause higher virus load, persistent fever, significant weight loss, moderate respiratory clinical signs, and severe histopathological lung lesions in piglets. PRRSV/CN/FJGD01/2021 exhibited higher pathogenicity than NADC30-like FJZ03 and NADC34-like FJ0908, but lower than Chinese HP-PRRSVs for piglets. These data indicated that PRRSV/CN/FJGD01/2021 has intermediate virulence for piglets. Furthermore, the Ingelvac PRRS MLV could partly provide protective efficacy against PRRSV/CN/FJGD01/2021 challenge in piglets.

Genetic and epidemic characteristics of porcine parvovirus 7 in the Fujian and Guangdong regions of southern China.

Porcine parvovirus (PPV) is the primary cause of reproductive disorders in pigs. The porcine parvovirus 7 (PPV7) subtype was first identified in the United States in 2016. In this study, PPV7 was detected in different porcine samples, including serum, feces, saliva, and milk, from 69 pig farms in the Fujian and Guangdong regions of South China, and its coinfection with porcine circovirus 2 (PCV2), porcine circovirus 3 (PCV3), and porcine reproductive and respiratory syndrome virus (PRRSV) was determined. Whole-genome sequencing, phylogenetic analysis, and recombination analysis were performed on seven isolates, with each selected isolate originating from a different farm. There was a high rate of PPV7 positivity in blood, stool, and saliva but PPV7 DNA was absent from breast milk. The findings also showed that PPV7-positive samples had a high rate of coinfection with PCV2, PCV3, and PRRSV. Real-time PCR was used to determine the viral copy numbers of PCV2, PCV3, PRRSV, and PPV7 in serum samples and to assess whether PPV7 affected PCV2, PCV3, and PRRSV viral loads. Phylogenetic analysis showed that PPV7e and PPV7f were the most prevalent and widespread subtypes in the Fujian and Guangdong regions, respectively. While the PPV7a, PPV7b, PPV7c, and PPV7f subtypes were most prevalent in Fujian Province, PPV7a-e subtypes were prevalent in Guangdong, indicating that PPV7 has rich genetic diversity in these regions. A putative recombinant strain, 21FJ09, was identified using SimPlot and the Recombination Detection Program 4 software.

Protective Effects of Lentinan Against Lipopolysaccharide-Induced Mastitis in Mice.

Mastitis is a worldwide production disease in dairy cows, which mainly affects milk yield, causing huge economic losses to dairy farmers. Lentinan is a kind of polysaccharide extracted from Lentinus edodes, which has no toxicity and possesses various pharmacological activities including antibacterial and immunomodulatory effects. Therefore, the anti-inflammatory function of lentinan on LPS-stimulated mastitis was carried out, and the mechanism involved was explored. In vivo, lentinan greatly reduced LPS-stimulated pathological injury, myeloperoxidase (MPO) activity, and the proinflammatory factor production (TNF-α and IL-1ß) in mice. Further study was performed to determine the activation of the Wnt/ß-catenin pathway during LPS stimulation. These results suggested that LPS-induced activation of the Wnt/ß-catenin pathway was suppressed by lentinan administration. In vitro, we observed that the mouse mammary epithelial cell (mMEC) viability was not affected by lentinan treatment. As expected, LPS increased the TNF-α and IL-1ß protein secretion and the activation of the Wnt/ß-catenin pathway that was inhibited by lentinan administration in a dose-dependent manner in mMECs. Conclusively, lentinan exerts the anti-inflammatory function in LPS-stimulated mastitis via inhibiting the activation of the Wnt/ß-catenin pathway. Thus, the results of our study also gave an insight that lentinan may serve as a potential treatment for mastitis.

Fisetin Ameliorates the Inflammation and Oxidative Stress in Lipopolysaccharide-Induced Endometritis.

PURPOSE: Fisetin is a natural flavone of polyphenol, which widely exists in many fruits and vegetables and has many pharmacological activities. However, the mechanism involved remains largely unknown. Here, we investigate the mechanisms of fisetin on the inflammatory response and oxidative stress in LPS-induced endometritis model and bovine endometrial epithelial cell line (BEND). METHODS: The function of fisetin was analyzed by network pharmacology. Effects of increasing doses of fisetin on inflammation and oxidative stress are studied in BALB/c mice with LPS-induced endometritis. The underlying mechanisms of antioxidant activity of fisetin were further explored in LPS-stimulated BEND cells. RESULTS: The results showed that fisetin significantly alleviated LPS-induced inflammatory injury and oxidative stress both in vivo and in vitro. Further studies found that fisetin greatly inhibited the LPS stimulated TLR4 expression and nuclear translocation of nuclear factor-κB (NF-κB), thus reducing the pro-inflammatory mediators secretion. Silencing TLR4 reduced LPS-induced inflammatory responses. Moreover, we observed that fisetin evidently decreased ROS production but activated Nrf2/HO-1 pathway in LPS-stimulated BEND cells. To further explore the role of Nrf2 in fisetin-induced HO-1 protein expression, the specific siRNA was used to silence Nrf2 expression. Silencing Nrf2 abrogated the inhibitory effects of fisetin on LPS-induced pro-inflammatory cytokines TNF-α, IL-1ß secretion, NADPH oxidase-4 (Nox4) and ROS production. CONCLUSION: In conclusion, fisetin effectively protected against LPS-induced oxidative stress and inflammatory responses which may be closely correlated to inhibition of TLR4-mediated ROS/NF-κB and activation of the Nrf2/HO-1 pathway.

Epidemiology investigation of PRRSV discharged by faecal and genetic variation of ORF5.

To obtain more information of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) transmission via faeces in/between farms, 360 swine faecal samples were randomly collected from different farms in China from 2017 to 2019. Sixty-two ORF5 genes were amplified by PCR from 120 positive samples identified by real-time RT-PCR and further characterized by sequencing. Phylogenetic analysis based on the ORF5 gene revealed that these strains can be divided into four lineages: lineage 1 (NADC30-like), lineage 3 (QYYZ-like), lineage 5.1 (VR2332-like) and lineage 8.7 (JXA1-like), with 62.9% (39/62) NADC30-like virus, 21% (13/62) QYYZ-like virus, 1.6% (1/62) VR2332-like virus and 14.5% (9/62) for JAX1-like virus. In particular, 14 PRRSVs including lineage 1, 5.1 and 8.7 can be isolated from 120 positive faecal samples, which further suggests that faecal transmission may be an important factor in the spread of PRRSV in farms. Full-length genome sequencing analysis showed that 14 isolates share 83.1%-97.7% homology with each other and 82.3%-96.1% identity with NADC30, 83.2%-99.7% with VR2332, 79.6%-87.2% with QYYZ and 82.6%-98.9% with JXA1 and CH-1a, and only 60.1%-60.7% with LV. Recombination events were observed in the six out of 14 strains. Collectively, the data of this study are useful for understanding the spread of PRRSV via faeces. Additionally, the virus was isolated from positive faecal samples, suggesting that faecal transmission may be an important factor in the spread of PRRSV in farms.

The four of structural genes sequences of a porcine epidemic diarrhea virus from domestic piglet in Fujian, China.

A prevalent PEDV strain, designated FJLY06, was isolated from Fujian, China. The four of structural genes sequences of PEDV obtained were analyzed to determine their phylogenetic relationships and homology respectively, revealing that FJLY06 was highly homologous to virulent PEDV strains. The four structural genes all differed genetically from the vaccine strain CV777. The sequence alignment results further showed that N, M and E genes of Chinese PEDV strains is highly conserved. Compared with the vaccine strain CV777, 8 mutations were detected in COE of FJLY06 S gene. The recombination analysis revealed FJLY06 is similar to other pandemic strains in China with a variant S gene, and maybe a reason for recent vaccination failures.

miR-148a suppresses inflammation in lipopolysaccharide-induced endometritis.

Endometritis is a postnatal reproductive disorder disease, which leads to great economic losses for the modern dairy industry. Emerging evidence indicates that microRNAs (miRNAs) play a pivotal role in a variety of diseases and have been identified as critical regulators of the innate immune response. Recent miRNome profile analysis revealed an altered expression level of miR-148a in cows with endometritis. Therefore, the present study aims to investigate the regulatory role of miR-148a in the innate immune response involved in endometritis and estimate its potential therapeutic value. Here, we found that miR-148a expression in lipopolysaccharide (LPS)-stimulated endometrial epithelial cells was significantly decreased. Our results also showed that overexpression of miR-148a using agomiR markedly reduced the production of pro-inflammatory cytokines, such as IL-1ß and TNF-α. Moreover, overexpression of miR-148a also suppressed NF-κB p65 activation by targeting the TLR4-mediated pathway. Subsequently, we further verified that miR-148a repressed TLR4 expression by binding to the 3'-UTR of TLR4 mRNA. Additionally, an experimental mouse endometritis model was employed to evaluate the therapeutic value of miR-148a. In vivo studies suggested that up-regulation of miR-148a alleviated the inflammatory conditions in the uterus as evidenced by H&E staining, qPCR and Western blot assays, while inhibition of miR-148a had inverse effects. Collectively, pharmacologic stabilization of miR-148a represents a novel therapy for endometritis and other inflammation-related diseases.

Full genome sequence analysis of a 1-7-4-like PRRSV strain in Fujian Province, China.

PRRS virus (PRRSV) has undergone rapid evolution and resulted in immense economic losses worldwide. In the present study, a PRRSV strain named FJ0908 causing high abortion rate (25%) and mortality (40%) was detected in a swine herd in China. To determine if a new PRRSV genotype had emerged, we characterized the genetic characteristics of FJ0908. Phylogenetic analysis indicated that FJ0908 was related to 1-7-4-like strains circulating in the United States since 2014. Furthermore, the ORF5 sequence restriction fragment length polymorphism (RFLP) pattern of FJ0908 was 1-7-4. Additionally, FJ0908 had a 100 aa deletion (aa329-428) within nsp2, as compared to VR-2332, and the deletion pattern was consistent with most of 1-7-4 PRRSVs. Collectively, the data of this study contribute to the understanding of 1-7-4-like PRRSV molecular epidemiology in China.

Efficacy of Type 2 PRRSV vaccine against challenge with the Chinese lineage 1 (NADC30-like) PRRSVs in pigs.

The objective of the present study was to determine the cross-protection of Ingelvac PRRS MLV against challenge with the new lineage 1 PRRSV emerged in China in pigs. Two lineage 1 PRRSV strains (FJZ03 and FJWQ16 originated from recombination event between NADC30 and JXA1-like strain). We found that pigs vaccinated with the vaccine were protected against challenge with the FJZ03 as shown by fewer days of clinical fever, reduced lung pathology scores, lower PRRS virus load in the blood and developed broadly neutralizing antibodies with high titers to FJZ03. In contrast, vaccine provided limited protection against challenge with FJWQ16 with higher fever, lower antibody titers, lower neutralizing antibodies and higher viral loads in blood. These results demonstrate PRRSV-MLV provides incomplete protection against new lineage 1 PRRSVs.

Emergence of a novel recombinant porcine circovirus type 2 in China: PCV2c and PCV2d recombinant.

Porcine circovirus type 2 (PCV2) has been causing huge economic losses in Chinese swine herds since it was first identified in China in 1999. Genotypes of PCV2 except for PCV2c coexist in swine herds in China, which may facilitate virus recombination. In the current study, six novel PCV2 strains were detected in China, and these strains shared high nucleotide similarity of the Rep gene with the PCV2c strain DK1987PMWSfree and high homology of the Cap gene with PCV2d. Genome sequence analysis revealed that the complete genomes of these strains were 1767 nucleotides (nt) in length and shared 99.8%-99.9% nucleotide identity with each other and 91.7%-98.7% with representative strains. Phylogenetic analysis, sequencing analysis, base-by-base comparisons and comprehensive recombination analysis demonstrated that these six strains originated from recombination within the Rep gene between PCV2c and PCV2d strains. Surprisingly, further investigation through theoretical recombination analysis of Chinese PCV2 GenBank sequences showed that these novel patterns of recombinant PCV2 strains have been generated since 2010. Collectively, our findings provide additional evidence of inter-genotypic recombination of PCV2.

Recombination in lineage 1, 3, 5 and 8 of porcine reproductive and respiratory syndrome viruses in China.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most important viral swine diseases, resulting in immense economic losses in Chinese pig industry. Currently, four major lineages: lineage 1 (NADC30-like), 3 (QYYZ-like), 5.1 (VR2332-like) and 8.7 (JXA1-like) of type 2 PRRSV (North American type) have been circulating in China based on classification system, which have caused concern about the potential of virus recombination. In the present study, a novel variant of PRRSV strain named FJLIUY-2017 was isolated from abortion rate (25%) in pregnant gilts in Fujian Province in China in 2017. To further our knowledge about the novel virus strain, we characterized the complete genome of FJLIUY-2017. Comparison to PRRS sequences in GenBank confirmed the absence of close relatives (<92%), but indicated FJLIUY-2017 belonged to NADC30-like PRRSV. The full length of FJLIUY-2017 was determined to be 15017 nucleotides (nt), excluding the poly(A) tail, shared 86.2-86.6% identity with JXA1-like strains (JXA1, TJ and FJYR), 88.9-90.6% with NADC30-like PRRSVs (NADC30, FJZ03 and CHsx1401), 86.4-86.5% with VR2332-like (VR2332, RespPRRS MLV and BJ-4) and only 60.8% with LV (European type). Recombination analyses revealed genomic breakpoints in structural (ORF3, ORF4 and ORF7) and nonstructural (Nsp1, Nsp2, Nsp6, Nsp9, Nsp11 and Nsp12) regions of the genomes with evidence for recombination events between lineages 1, 3, 5.1 and 8.7. Taken altogether, the results of our study provide further confirmation that PRRSV is prone to undergo recombination events. Thus, it is critical to monitor PRRSV evolution in China and establish an effective strategy for the control of PRRS.

Nuciferine alleviates LPS-induced mastitis in mice via suppressing the TLR4-NF-κB signaling pathway.

BACKGROUND: Nuciferine, a major bioactive component from the lotus leaf, has been reported to have notable anti-inflammatory activities such as renal inflammation and acute lung injury in previous studies. Mastitis is one of the most prevalent diseases in the dairy cattle, which causes large economic losses for the dairy industry. However, the effects of nuciferine on lipopolysaccharide (LPS)-induced mastitis have not been reported. METHODS AND RESULTS: Here, we investigated the anti-inflammatory effects of nuciferine on LPS-induced mastitis in mice and illuminated its potential mechanism on the TLR4-mediated signaling pathway in mouse mammary epithelial cells (mMECs). Histopathological changes and myeloperoxidase (MPO) activity assay showed that nuciferine treatment significantly alleviated the LPS-induced injury of mammary gland flocculus, inflammatory cells infiltration. qPCR and ELISA assays indicated that nuciferine dose-dependently reduced the levels of TNF-α and IL-1ß, which indicated that nuciferine might have therapeutic effects on mastitis. Furthermore, nuciferine treatment significantly decreased the expression of TLR4 in a dose-dependent manner. Besides, nuciferine was also found to suppress LPS-induced NF-κB activation. CONCLUSION: These findings indicate that nuciferine potently ameliorates LPS-induced mastitis by inhibition of the TLR4-NF-κB signaling pathway.

[Construction of recombinant PRRSV ORF5 gene by DNA shuffling technique].

Recombinant PRRSV △2ORF5 gene was constructed using DNA shuffling from four genetically different strains of PRRSV to study its heterologous cross-neutralizing ability. The △2ORF5 mutant gene was cloned into the vector pET-32a and transferred into E. coli BL21. SDS-PAGE confirmed that the molecular weight of the recombinant △2ORF5 was about 42 kDa, consistent with the predicted result. Then the purified recombinant protein was injected into BALB/c mouse to obtain polyclonal antibody. Western blotting analysis with mouse-anti-△2ORF5 polyclonal serum indicated that the parental virus recombinant GP5 protein reacted with the specific antibodies. Four parental viruses could be inhibited by the anti-△2ORF5 polyclonal antibody and the inhibition rates were higher than 53%. This work has laid a foundation for further development vaccine for PRRSV.

Leonurine ameliorates the inflammatory responses in lipopolysaccharide-induced endometritis.

Endometritis is the inflammation of the endometrium that is associated with lower conception rates, increased intervals from calving to first service, and more culls for failure to conceive, which leads to serious economic losses in the dairy industry. Leonurine, a natural active compound of Leonurus cardiaca, has been proved to possess various biological activities. However, there is still no study about its anti-inflammatory effects on LPS-induced endometritis. The present study aimed to demonstrate the underlying mechanism responsible for the anti-inflammatory effects of leonurine on LPS induced endometritis in mice and in bovine endometrial epithelial cells (bEECs). The results of pathological section displayed that leonurine alleviated LPS induced uterine injury. qRT-PCR and ELISA experiments suggested that leonurine inhibited the expression levels of TNF-α and IL-1ß in uterus tissues and bEECs. Molecular studies showed that TLR4 expression and nuclear factor (NF)-κB activation were both inhibited by leonurine treatment. These results suggested that the therapeutic effects of leonurine on LPS-induced endometritis in mice and bEECs may act by inhibiting the expression of TLR4 and its downstream mediated NF-κB pathway. Accordingly, leonurine may serve as an effective drug in preventing and treating LPS induced endometritis.

Detection of PCV2e strains in Southeast China.

Porcine circovirus 2 (PCV2) has been prevalent in swine herds in China since 2002, causing severe economic loss to the pig industry. The number of live pigs in southeast China is > 20 million. Since information on the genetic variation of PCV2 in the Fujian province is limited, the objective of the present work was to investigate the epidemiological and evolutionary characteristics of PCV2 in southeast China from 2013 to 2017. Of the 685 samples collected from 90 different swine herds from 2013 to 2017, 356 samples from 84 different swine herds were positive for PCV2. PCV2a, PCV2b, PCV2d, and PCV2e co-existed in the Fujian province, with PCV2d being the predominant circulating strain in swineherds and PCV2e being reported for the first time in China. Strikingly, PCV2-FJ-water DNA comes from contaminated river water and not infected animals. Sequence comparison among all isolates indicated that 95 isolates shared approximately 78.7%-100% nucleotide identity and 74.5%-100% amino acid identity for open reading frame 2 (ORF2). Amino acid alignment showed that the Cap protein of PCV2e differed markedly from those of PCV2a, PCV2b, PCV2c, and PCV2d. These results indicated that various PCV2 genotypes exist in China, and that PCV2 is continuously evolving, leading to rapid emergence of new variant stains.

Genetic diversity and evolutionary characteristics of type 2 porcine reproductive and respiratory syndrome virus in southeastern China from 2009 to 2014.

The objective of this study was to assess the genetic diversity of porcine reproductive and respiratory syndrome virus circulating in Fujian province (southeastern China). Based on 53 ORF5 nucleotide sequences collected from nine sites, both highly pathogenic (sublineage 8.7) and lineage 1 strains were circulating in Fujian in 2009-2014 along with lineages 3 and 5.1. Notably, the lineage 1 strains were closely related to the NADC30 strain circulating in North America and were the predominant strains in 2014. In addition, we found that nonstructural protein 2 (NSP2) was the most variable nonstructural protein in Fujian isolates, with a 36-amino-acid (aa) insertion and seven different deletions detected in the 53 sequences examined. Similarly, analysis of GP5 amino acid sequences showed that the isolates were highly variable in primary neutralizing epitopes. Interesting, FJ3.2 and FJ7-2 strains have the mutation N44K, but they exhibited high replication and high titers in MARC-145 and PAM cells. The complete genome sequences determined for 12 type 2 isolates were 82.1-99.3% identical and were 15,016-15,407 nucleotides (nt), in length excluding the poly(A) tail. The strains also shared 88.2-99.4% identity with strain VR2332 (the prototype North American strain), 83.4-99.2% identity with strain JXA1 (the prototype high-pathogenicity Chinese strain), 88.2-97.1% identity with strain CH-1a (the prototype classical Chinese strain), and 82.9-97.1% identity with strain NADC30 (the prototype NADC30-like strain). Strikingly, phylogenetic and molecular evolutionary analyses indicated that strain FJW05 is a spontaneous recombinant between a circulating lineage 1 virus and the vaccine strain JXA1-R, which is derived from the highly pathogenic strain JXA-1. Collectively, the data highlight the epidemiology of porcine reproductive and respiratory syndrome in Fujian and may aid in selecting a suitable vaccine for use on pig farms.

Recombination in JXA1-R vaccine and NADC30-like strain of porcine reproductive and respiratory syndrome viruses.

Porcine reproductive and respiratory syndrome (PRRS) is considered one of the most devastating swine diseases worldwide, resulting in immense economic losses. PRRS virus (PRRSV) has undergone rapid evolution since its first recognition in 1990s. In the present study, a PRRSV strain named FJXS15 causing high morbidity and mortality was isolated from piglets and sows from a farm participating in vaccination in China. Phylogenetic and molecular evolutionary analyses revealed that FJXS15 was highly similar to the JXA1-R vaccine strain (a live attenuated virus vaccine strain derived from the highly pathogenic PRRSV JXA1) in the ORF1a (nt 901-)-ORF4 (-nt 419) coding regions, as well as to FJZ03 (lineage 1, NADC30-like) in the 5'-UTR, ORF5a-ORF7 coding regions, and 3'-UTR, suggestive of a natural recombination event. Recombination analyses showed that recombination events occurred in two inter-lineage recombination events between Lineages 1 and 8 based on based on classification system (Shi et al., 2010), and two recombination breakpoints at positions 1-1092 and 13771-15537 of the sequence alignment (with reference to the VR-2332 strain). Animal experiments demonstrated that FJXS15-infected animals had more severe histopathological lung lesions than did JXA1-R-infected and control groups. A 25% mortality rate was found in FJXS15-infected piglets, which was similar to that found with other Chinese HP-PRRSV strains. Thus, the recombinant virus is a highly virulent PRRSV. Moreover, this report provides evidence for inter-subgenotypic recombination between the JXA1-R vaccine virus and a circulating Lineage 1 virus.

Omp16-based vaccine encapsulated by alginate-chitosan microspheres provides significant protection against Haemophilus parasuis in mice.

Haemophilus parasuis (H. parasuis) is the etiological agent of swine Glässer's disease, which leads to significant economic loss in swine industry over the world. Subunit vaccine based on outer membrane protein is one of the promising choices to protect pigs against H. parasuis infection despite low immunity efficiency. In this paper, outer membrane protein 16 (Omp16) of H. parasuis encapsulated by alginate-chitosan microspheres as antigen carriers was explored for the first time in a mouse model. Our results showed that the microspheres with Omp16 induced significant higher H. parasuis-specific antibodies, and higher titers of IL-2, IL-4, and IFN-γ than those by Omp16-FIA in treated mice (p<0.05). Moreover, H. parasuis load in the tissues from liver, spleen, and lung of mice immunized with microspheres containing Omp16 was significantly decreased (p<0.05) than that in the same counterpart tissues of control groups. In addition, 80% mice treated with Omp16 and 70% mice with Omp16-FIA were survived after challenged with H. parasuis virulent strain LY02 (serovar 5). Therefore, Omp16-based microsphere vaccine induces both humoral and cellular immune responses and provides promising protection against H. parasuis infection in mice.

Complete genomic characterization of two European-genotype porcine reproductive and respiratory syndrome virus isolates in Fujian province of China.

Porcine reproductive and respiratory syndrome (PRRS) is considered one of the most devastating swine diseases worldwide, resulting in immense economic losses. PRRS virus (PRRSV) is divided into two major genotypes, European (type 1) and the North American (type 2). Type 1 PRRSV have recently emerged in Fujian province (South China), and this might have a significant impact on the Chinese pig industry. From 2013 to 2014, two type 1 PRRSV strains, named FJEU13 and FJQEU14, were isolated from piglets and sows with respiratory problems and reproductive disorders in Fujian province. The full genome length of the two isolates was 14,869-15,062 nucleotides (nt), excluding the poly(A) tail. These isolates shared 86.0-89.9% sequence identity with the prototypic strains Lelystad virus (LV) and 82.8-92% with Chinese type 1 PRRSV strains, but only 59.9-60.1% with the North American reference strain VR-2332. However, they were 82.9% identical to each other. Nonstructural protein 2 (Nsp2) and ORF3-ORF5 were the most variable regions when compared to other type 1 PRRSV strains. Nsp2 and ORF3 contained multiple discontinuous deletions and a 204-bp deletion in NSP2 in isolate FJQEU14, which has never been described in other Chinese type 1 PRRSV strains. All of these results might be useful for understanding the epidemic status of type 1 PRRSV in China.