scholarly journals Seroprevalences of Classical Swine Fever Virus and Porcine Reproductive and Respiratory Syndrome Virus in Pigs in Hunan Province, China

2020 ◽  
Author(s):  
Haoyang Yu ◽  
Luhua Zhang ◽  
Yunfeng Cai ◽  
Tao Peng ◽  
Lei Liu ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Classical Swine Fever Virus ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Central China ◽  
Hunan Province ◽  
Economic Losses ◽  
Respiratory Syndrome Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Growth Stages

Abstract Background: Several infectious diseases including classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Hunan is a province in south-central China, serological statistics will have certain effect on local breeding industry.The present study investigated the seroprevalences of classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV) in pigs from eight cities of Hunan province from 2017 to 2019. The samples were divided into two groups based on whether the hosts were immunized or not, and analysed by enzyme-linked immunosorbent assay (ELISA).Results: The seropositivity of CSFV and PRRSV between different parts of Hunan province in China was statistically significant. In unvaccinated group, our findings showed CSFV antibody in piglets' sera decreases gradually with increase of piglets' age whereas PRRSV-specific antibodies may appear in various growth stages. In immunized group, the average seropositive rate of CSFV antibody was 82.2%, while the rate of PRRSV antibody was relatively higher (84.4%).Conclusions: Results from this study suggested that a serological investigation on these two major infectious diseases (CSF and PRRS) among various growth stages of pigs will provide a basis for further development of more effective preventions and control measures.

scholarly journals Seroprevalences of classical swine fever virus and porcine reproductive and respiratory syndrome virus in pigs in Hunan Province, China

2020 ◽  
Author(s):  
Haoyang Yu ◽  
Luhua Zhang ◽  
Yunfeng Cai ◽  
Tao Peng ◽  
Lei Liu ◽  
...  
Keyword(s):  
Average Rate ◽  
Classical Swine Fever ◽  
Control Measures ◽  
Hunan Province ◽  
Economic Losses ◽  
Respiratory Syndrome Virus ◽  
Growth Stages ◽  
Serum Samples ◽  
Swine Industry ◽  
Effective Prevention

Abstract Background: Classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Routine surveillance serology for CSF and PRRS will be critical to maintain the health status of sow farms in Hunan Province, which is one of the top pig production provinces in China.The objective of our study was to investigate the seroprevalence of CSF virus (CSFV) and PRRS virus (PRRSV) in Hunan Province from 2017 to 2019 using ELISA. The cohort pig serum samples were collected from vaccinated and unvaccinated sow farms in eight cities in Hunan Province. Results: CSFV and PRRSV seropositivity showed significant differences among parts of Hunan Province in China. Interestingly, our findings show that the level of CSFV antibody in piglet sera decreases gradually with increasing piglet age, whereas PRRSV-specific antibodies may appear in various growth stages in unvaccinated animals. Meanwhile, the average rate of CSFV antibody seropositivity was 82.2%, while the rate of PRRSV antibody seropositivity was slightly higher (84.4%) in the immunized group.Conclusions: The results from this study suggest that a serological investigation of these two major infectious diseases (CSF and PRRS) among pigs at various growth stages will provide a basis for the further development of more effective prevention and control measures.

scholarly journals Identification of E2 with improved secretion and immunogenicity against CSFV in piglets

2020 ◽  
Author(s):  
Huiling Xu ◽  
Yanli Wang ◽  
Guangwei Han ◽  
Weihuan Fang ◽  
fang he
Keyword(s):  
Single Dose ◽  
Signal Peptide ◽  
Classical Swine Fever Virus ◽  
Subunit Vaccine ◽  
Classical Swine Fever ◽  
Cost Effective ◽  
Fever Virus ◽  
Economic Losses ◽  
Swine Industry ◽  
Virus Challenge

Abstract Background: Outbreaks of Classical swine fever virus (CSFV) cause significant economic losses in the swine industry. Vaccination is the major method to prevent and control the disease. As live attenuated vaccines fail to elicit differentiable immunity between infected and vaccinated animals, subunit vaccine was considered as an alternative candidate to prevent and eradicate CSFV. Subunit vaccines present advantages in DIVA immunogenicity and safety. The technology was limited due to the low yield and the high cost with multiple and large doses. The native E2 signal peptide has not been well defined before. Here, the aim of this study is to develop a cost-effective and efficacious E2 vaccine candidate against CSFV with signal peptide and E2 sequence selection. Results: A novel CSFV E2 sequence (E2ZJ) was identified from an epidemic strain of Zhejiang for outstanding secretion in baculovirus and enhanced immunogenicity. E2 secretion induced with the selected signal peptide, SPZJ (SP23), increase at least 50% as compared to any other signal peptides tested. Besides, unique antigenic features were identified in E2ZJ. E2ZJ elicited CSFV antibodies at the earlier stage than other E2 types tested in mice. Moreover, higher level of neutralization antibodies against both genotypes 1 and 2 CSFV with E2ZJ was detected than other E2s with the same dosage. Further, in piglets, E2ZJ successfully elicited neutralizing immunity. A single dose of 5 μg of E2ZJ was sufficient to induce protective antibodies against CSFV in piglets and provided 100% protection against lethal virus challenge. Conclusions: Our studies provide evidence that E2ZJ guided by a novel E2 signal peptide (SPZJ) was efficiently secreted and presented significantly improved immunogenicity than conventional E2 vaccines. Moreover, a single dose of 5 μg E2ZJ is efficacious against CSFV in piglets. Keywords: Classical swine fever virus; novel signal peptide; SPZJ-E2ZJ; subunit vaccine; protective immunity

scholarly journals Immunogenicity in Swine of Orally Administered Recombinant Lactobacillus plantarum Expressing Classical Swine Fever Virus E2 Protein in Conjunction with Thymosin α-1 as an Adjuvant

2015 ◽  
Vol 81 (11) ◽  
pp. 3745-3752 ◽  
Author(s):  
Yi-Gang Xu ◽  
Xue-Ting Guan ◽  
Zhong-Mei Liu ◽  
Chang-Yong Tian ◽  
Li-Chun Cui
Keyword(s):  
Immune Responses ◽  
Lactobacillus Plantarum ◽  
Classical Swine Fever Virus ◽  
Oral Vaccine ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Economic Losses ◽  
E2 Protein ◽  
Content Type ◽  
Cellular Immune

ABSTRACTClassical swine fever, caused by classical swine fever virus (CSFV), is a highly contagious disease that results in enormous economic losses in pig industries. The E2 protein is one of the main structural proteins of CSFV and is capable of inducing CSFV-neutralizing antibodies and cytotoxic T lymphocyte (CTL) activitiesin vivo. Thymosin α-1 (Tα1), an immune-modifier peptide, plays a very important role in the cellular immune response. In this study, genetically engineeredLactobacillus plantarumbacteria expressing CSFV E2 protein alone (L. plantarum/pYG-E2) and in combination with Tα1 (L. plantarum/pYG-E2-Tα1) were developed, and the immunogenicity of each as an oral vaccine to induce protective immunity against CSFV in pigs was evaluated. The results showed that recombinantL. plantarum/pYG-E2 andL. plantarum/pYG-E2-Tα1 were both able to effectively induce protective immune responses in pigs against CSFV infection by eliciting immunoglobulin A (IgA)-based mucosal, immunoglobulin G (IgG)-based humoral, and CTL-based cellular immune responses via oral vaccination. Significant differences (P< 0.05) in the levels of immune responses were observed betweenL. plantarum/pYG-E2-Tα1 andL. plantarum/pYG-E2, suggesting a better immunogenicity ofL. plantarum/pYG-E2-Tα1 as a result of the Tα1 molecular adjuvant that can enhance immune responsiveness and augment specific lymphocyte functions. Our data suggest that the recombinantLactobacillusmicroecological agent expressing CSFV E2 protein combined with Tα1 as an adjuvant provides a promising strategy for vaccine development against CSFV.

scholarly journals Complete Genome Sequence of a Classical Swine Fever Virus Isolate Belonging to New Subgenotype 2.1d from Henan Province, Central China

2016 ◽  
Vol 4 (3) ◽  
Author(s):  
Chaochao Lv ◽  
Qingyuan Yang ◽  
Xiaojing Gao ◽  
Yali Yao ◽  
Xiangdong Li ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Classical Swine Fever Virus ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Virus Isolate ◽  
Field Isolate ◽  
Classical Swine Fever ◽  
Glycosylation Site ◽  
Fever Virus ◽  
Central China

We report here the complete genome sequence of HeN1505, a field isolate of classical swine fever virus belonging to the new subgenotype 2.1d. HeN1505 distinguishes itself from other classical swine fever virus (CSFVs) by 1 amino acid substitution in position 159 (threonine by isoleucine), which led to the loss of one N -glycosylation site in the N pro protein.

scholarly journals Crystal Structure of Classical Swine Fever Virus NS5B Reveals a Novel N-Terminal Domain

2018 ◽  
Vol 92 (14) ◽  
Author(s):  
Weiwei Li ◽  
Baixing Wu ◽  
Wibowo Adian Soca ◽  
Lei An
Keyword(s):  
Crystal Structure ◽  
Rna Polymerase ◽  
Classical Swine Fever Virus ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Structural Basis ◽  
Economic Losses ◽  
Rna Dependent Rna Polymerase ◽  
Content Type ◽  
Terminal Domain

ABSTRACTClassical swine fever virus (CSFV) is the cause of classical swine fever (CSF). Nonstructural protein 5B (NS5B) is an RNA-dependent RNA polymerase (RdRp) that is a key enzyme initiating viral RNA replication by ade novomechanism. It is also an attractive target for the development of anti-CSFV drugs. To gain a better understanding of the mechanism of CSFV RNA synthesis, here, we solved the first crystal structure of CSFV NS5B. Our studies show that the CSFV NS5B RdRp contains the characteristic finger, palm, and thumb domains, as well as a unique N-terminal domain (NTD) that has never been observed. Mutagenesis studies on NS5B validated the importance of the NTD in the catalytic activity of this novel RNA-dependent RNA polymerase. Moreover, our results shed light on CSFV infection.IMPORTANCEPigs are important domesticated animals. However, a highly contagious viral disease named classical swine fever (CSF) causes devastating economic losses. Classical swine fever virus (CSFV), the primary cause of CSF, is a positive-sense single-stranded RNA virus belonging to the genusPestivirus, familyFlaviviridae. Genome replication of CSFV depends on an RNA-dependent RNA polymerase (RdRp) known as NS5B. However, the structure of CSFV NS5B has never been reported, and the mechanism of CSFV replication is poorly understood. Here, we solve the first crystal structure of CSFV NS5B and analyze the functions of the characteristic finger, palm, and thumb domains. Additionally, our structure revealed the presence of a novel N-terminal domain (NTD). Biochemical studies demonstrated that the NTD of CSFV NS5B is very important for RdRp activity. Collectively, our studies provide a structural basis for future rational design of anti-CSFV drugs, which is critically important, as no effective anti-CSFV drugs have been developed.

scholarly journals Application of Competitive Enzyme-Linked Immunosorbent Assay for the Serologic Diagnosis of Classical Swine Fever Virus Infection

2001 ◽  
Vol 13 (4) ◽  
pp. 357-360 ◽  
Author(s):  
Alfonso Clavijo ◽  
Min Lin ◽  
José Riva ◽  
En-Min Zhou
Keyword(s):  
Immunosorbent Assay ◽  
Classical Swine Fever Virus ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Prevalence Studies ◽  
Specificity And Sensitivity ◽  
Kappa Value ◽  
Relative Specificity ◽  
Level Of Agreement

A competitive enzyme-linked immunosorbent assay (C-ELISA), based on a truncated E2 recombinant protein of the Alfort/187 strain of classical swine fever virus (CSFV) and a specific monoclonal antibody M1669, was evaluated using 2,000 sera from clinically healthy pigs in Canada (a CSFV-free country) and sera from experimentally infected pigs. The relative specificity and sensitivity of the C-ELISA were 100% and 86%, respectively, at a cutoff of 25% inhibition using negative and positive pig sera, as defined by the neutralizing peroxidase-linked assay (NPLA). A kappa value of 0.91 was obtained, indicating an excellent level of agreement between the NPLA and the C-ELISA. When sera from 120 infected pigs were used in the test at ≥21 days postinfection, the sensitivity of the C-ELISA and the kappa value increased to 97% and 0.98, respectively. This C-ELISA will be useful when a large number of samples must be tested, as could occur during a disease outbreak or for surveillance or prevalence studies.

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