Porcine circovirus type 2(PCV2),which serves as a major causative agent of PCV2-associated diseases and causes severe loss to the pig industry worldwide,can dysregulate the immune response and induce immunosuppression...Porcine circovirus type 2(PCV2),which serves as a major causative agent of PCV2-associated diseases and causes severe loss to the pig industry worldwide,can dysregulate the immune response and induce immunosuppression in PCV2-infected pigs.Similar to PCV2(porcine circovirus type 3(PCV3),a newly identified swine circovirus which might be closely associated with porcine dermatitis and nephropathy syndrome,reproductive disorder,and multisystemic inflammatoty responses,also interferes with host immune defense.Interaction between host immune system and PCVs is considered to be a crucial determinant of pathogenicity in pigs.Here,we sought to briefly discuss the current knowledge regarding the interaction of porcine circovirus type 2 and/or 3 with host immune cells and immune responses to better depict the viral immunomodulatory capacity,pathogenic mechanisms,and the future research direction in host immune responses to infection with PCV2 and PCV3.展开更多
Porcine cimovirus (PCV) is the smallest animal virus so far and has two serotypes. PCV1 is nonpathogenic, but PCV2 is pathogenic and causes post-weaning multisystemic wasting syndrome ( PMWS). Factors to induce PM...Porcine cimovirus (PCV) is the smallest animal virus so far and has two serotypes. PCV1 is nonpathogenic, but PCV2 is pathogenic and causes post-weaning multisystemic wasting syndrome ( PMWS). Factors to induce PMWS include immunity and infection status of sows, infec- tion time, mixed infection, PCV2 variants, physical status of gilts, and feeding management. For final diagnosis, histopathological changes and ex- istence of PCV2 in lymphoid tissues are professional standards, because fluorescence quantitative RT-PCR is not enough specific or sensitive. The commemial PCV2 vaccines can reduce occurrence of PMWS and PCV-related diseases. This paper reviews recent advances in epidemiology of PCV2 as well as diagnosis and control of PMWS.展开更多
[ Objective] This study aimed to investigate the molecular characteristics of porcine circovirus type 2 (PCV2) strains isolated from Hainan Province. [ Method] The complete genome of PCV2 was amplified from PMWS-sus...[ Objective] This study aimed to investigate the molecular characteristics of porcine circovirus type 2 (PCV2) strains isolated from Hainan Province. [ Method] The complete genome of PCV2 was amplified from PMWS-suspected samples by PCR for sequence analysis. [ Result] A total of eight PCV2 strains were isolated and identified. All the eight isolates belonged to genotype PCV2b, among which seven isolates belonged to subgenotype PCV2b-1 C, and one isolate be- longed to subgenotype PCV2b-IA/1B. ORF2 gene of PCV2 isolates from Hainan Province was 705 bp in length, encoding 234 amino acids. Antigenic epitopes of Cap protein exhibited certain changes. Nucleotide sequences and deduced amino acid sequences of ORF2 gene shared 95.3% -99.7% and 93.6% - 100% simi- larities among eight PCV2 isolates from Hainan Province, respectively. Moreover, nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 91.0% -99.9% and 91.0% -99.6% similarities with other PCV2 strain isolated from China (AY682994, AF381175, JX945577, JX682407, AY180397 ), respectively; nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 90.0% - 97.0% and 88.0% -97.9% similarities with PCV2 isolates from other countries ( NC_005148, JQ994268, KJ187306, AF201307, AF454546, AY"/Sd020), respectively; nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 98.2% -100% and 94.9% -100% similarities with vaccine strain SH, respectively; nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 90.6% -91.7% and 89.7% - 91.0% similarities with vaccine strain LG, respectively. [ Conclusion] This study provided theoretical hasis for the prevention and control of PCV2 and selection of vaccine strains in Hainan Province.展开更多
The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein (EGFP) report gene. ORF2 gene of porcine circovirus type 2 cloned ...The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein (EGFP) report gene. ORF2 gene of porcine circovirus type 2 cloned by PCR was ligated to the expression vector pEGFP-N1, which contains enhanced green fluorescent protein (EGFP) report gene, the recombinant eukaryotic expression plasmid pEGFP-N1-ORF2 was constructed successfully and was transfected into pre- pared duck myocardial cells (DMCs) by lipofectin. According to the result, the fluorescence expression was directly detected with fluorescence microscope, and the expression of ORF2 were analyzed by RT-PCR and indirect immunofluorescence assay (IFA) respectively. About 48 h after transfection, green fluorescent can be observed on transfected cells : T-PCR and IFA were positive. This indicated that ORF2 gene of PCV2 was expressed efficiently in transfected duck myocardial cells.展开更多
Porcine cimovirus type 2 (PCV2) infection causes huge economic losses, but no serological method is available for batch detection of field samples. The aim of the study was to develop a method for large-batch detectio...Porcine cimovirus type 2 (PCV2) infection causes huge economic losses, but no serological method is available for batch detection of field samples. The aim of the study was to develop a method for large-batch detection of PCV2 infection. Colloidal gold-labeled staphylococcal protein A (SPA) was sprayed on glass fibers to prepare a conjugate pad. The recombinant ORF2 protein of PCV2 was blotted on the test line of the nitrocellulose (NC) membrane, and pig IgG was streaked on the control line of the NC membrane. Then, the immunochromatographic strip was used for detection of antibodies against PCV2. The results show that the strip test was simple and the results could be determined within 10 min with naked eyes. The test strip was highly specific for pig serum against PCV2 and no cross-reaction with pig serum against other pathogens was observed. The test strip had close similarity with ELISA. Storage at RT for 6 months did not affect the specificity and sensitivity obviously. A total of 324 clinical pig sera were detected by both ELISA and the developed test strip, and the coincidence was 98.77%. Therefore, the developed immunochromatographic strip is specific, sensitive, stable, fast and simple, and it is suitable for on-site detection of antibodies against PCV2.展开更多
[ Objective] The study aimed to analyze the prevalence of Porcine Parvovirus (PPV) and Porcine Circovirus Type 2 ( PCV2 ) and the mixed infection in Sichuan Province to lay the foundation for further predicting th...[ Objective] The study aimed to analyze the prevalence of Porcine Parvovirus (PPV) and Porcine Circovirus Type 2 ( PCV2 ) and the mixed infection in Sichuan Province to lay the foundation for further predicting the tendency of the plague and formulating appropriate prevention and control strategies. [ Method] Two hundred and seventy -three samples were collected from 21 large pig farms in Sichuan province, and epidemiology of PPV and PCV2 were investigated by PCR detecting. [ Result] The positive rate of PPV was 17.22% (47/273), and positive rate of pig farms was 38.1% (8/21), meanwhile it also displayed the feature that infection rate of boar was higher than that of piglets; The positive rate of PCV2 was 52.38% (143/273), and positive rate of pig farms was 85.7% (18/21), and it showed the trend that the infection rate of PCV2 was rising with the growth of the age. The co-infection rate of PPV and PCV2 was 10.62% (29/273), and co-infection rate of pig farms was 28.7% (6/21), which mainly concentrated in the sow and nursery piglets. Only 14.3% (3/21) pig farms was epidemiologically negative of PPV and PCV2. [ Conclusion] PPV and PCV2 and co-infection was widely popular in Sichuan province, and it did more serious harm to the pig-raising industry.展开更多
[ Objective ] To establish a real-time fluorescent quantitative polymerase chain reaction (PCR) method with SYBR Green I for the detection of porcine circovirus type 2 (PCV2). [Methods] Specific primers were desig...[ Objective ] To establish a real-time fluorescent quantitative polymerase chain reaction (PCR) method with SYBR Green I for the detection of porcine circovirus type 2 (PCV2). [Methods] Specific primers were designed to amplify the conserved gene segments of PCV2 with a size of 177 bp by PCR. The ampli- fied gene was cloned into the vector of pMD 18-T and transformed into DHSct to screen positive clones. After being extracted and purified, the recombinant plasraids pMD 18-T-177 were taken as the standard DNA templates to establish the fluorescence quantitative PCR method for the detection of PCV2, and the PCR re- action conditions were optimized. [ Results] Ct value of the established PCR method showed a good linear relationship with the standard DNA templates within a viral load of 3.21 × 100 -4.16 × 108 copies/μL , the correlation coefficient was O. 998 8 and the slope was - 3.286. The method did not show any cress-reactions with the genomes of PRRSV, PCV1, CSFV, PRV, PPV and Escherichia coli. Sensitivity of this method was proved to be 3.21 × 10 copies/μL, which was 1 000 times higher as conventional PCR method. Variation coefficients of the repeated trims among same batch or different batches were both less than 3.00%. Positive rate of clinical samples detected by the established PCR method was 58.94%, which was significantly higher than the detection rate by conventional PCR. [ Conclusions ] A reM-time fluorescent quantitative PCR method with SYBR Green I for the detection of PCV2 was established, which was better for conducting the quan- titative analysis and the early diagnosis of PCV2 infection.展开更多
The development history, etiology, epidemiology, clinical symptoms, pathological changes and diagnosis technology of porcine circovirus 3 were summarized, and countermeasures for prevention and control of the disease ...The development history, etiology, epidemiology, clinical symptoms, pathological changes and diagnosis technology of porcine circovirus 3 were summarized, and countermeasures for prevention and control of the disease were put forward based on the prevalence status in China.展开更多
In September 2011, an infectious disease suspected to be postweaning multisystemic wasting syndrome (PMWS) broke out in some pig farm in Taizhou. The inguinal lymph node, liver and lung tissues were collected and gr...In September 2011, an infectious disease suspected to be postweaning multisystemic wasting syndrome (PMWS) broke out in some pig farm in Taizhou. The inguinal lymph node, liver and lung tissues were collected and grinded into tissue suspension. The suspension was subjected to PCR detection, and the positive product was sequenced. The suspension of positive samples was filtered with 0.22 μm filter membrane, and the filtrate was inoculated onto PK15 cells. After five generations of blind passages, the cell viral liquid was collected and extracted for DNA, which was subjected to PCR detection and indirect immunofluorescence. The results showed that the isolate was porcine circovirus type 2 (PCV2) and designated as TAIZ110926. The target sequence was committed to NCBI with a serial number: KF039888.展开更多
In order to obtain induction expressed porcine circovirus type 2(PCV2)multi-epitope with good immunogenicity in vitro.Major epitopes of PCV2 were screened in the test,epitopes were composed sequentially,the c DNA se...In order to obtain induction expressed porcine circovirus type 2(PCV2)multi-epitope with good immunogenicity in vitro.Major epitopes of PCV2 were screened in the test,epitopes were composed sequentially,the c DNA sequences were artificially synthesized.Bam HⅠand SalⅠwere directionally cloned into prokaryotic expression vector PEGX-4T-1 multiple cloning site,then BL21 competent cells were transformed,positive clones were screened,IPTG inducible expression was conducted.Expression on target gene was analyzed by SDS-PAGE,fusion protein polypeptide was extracted and purified,immunocompetence of the expressed multi-epitope protein was identified by Westernblot.BALB/c mouse was immuned by fusion protein polypeptide,the antibody was determined by ELISA,immunogenicity was evaluated.Results showed that expression recombinant plasmid pEGX-4T-1-ep contained with seven PCV2 antigen epitopes had been constructed successfully.SDS-PAGE analysis showed that fusion protein polypeptide was expressed effectively in Escherichia coli(E.coli),and the molecular weight was about 35ku,which existed in the form of solubility.Results of Westernblot showed that the extraction and purification of fusion protein polypeptide and PCV2 positive serum had good reactogenicity.Results of ELISA showed that the purified fusion protein polypeptide could stimulate the body to produce PCV2 specific antibody which had good immunogenicity.Results indicated that the constructed PCV2 multi-epitope had good expression characteristics in vitro,and the expression protein had good immunogenicity.The study provided a basic for the study on PCV2 epitope screening,functional identification and multi-epitope vaccine.展开更多
Porcine circovirus type 3(PCV3),which was first detected in the United States of America in 2015,is a potential threat to the swine industry.However,the prevalence of PCV3 in Shanxi Province,China,is unclear.In this r...Porcine circovirus type 3(PCV3),which was first detected in the United States of America in 2015,is a potential threat to the swine industry.However,the prevalence of PCV3 in Shanxi Province,China,is unclear.In this research,the prevalence and genetic diversity of PCV3 were investigated in above area.Lung tissue samples(n=491)from 19 pig slaughterhouses across 11 cities throughout Shanxi Province were analyzed for PCV3 infection by PCR in 2019.The results showed that PCV3 positive rates in slaughterhouses and individuals were 100%(19/19)and 86.76%(426/491),respectively.PCV2 and PCV3 double-positive rates in slaughterhouses and individuals were 100%(19/19)and 59.27%(291/491),respectively.PCR positive samples were further sequenced and 8 PCV3 isolates were identified.The nucleotide homology of these isolates with other PCV3 isolates in NCBI database was 97.45-99.90%.A phylogenetic analysis,based on the complete genomic sequence and ORF2,divided these PCV3 strains into 2 major groups.Based on A24A/and R27/K amino acid mutations of capsid protein,the 8 identified PCV3 strains were separated to 2 clades.This was the first detailed investigation into the epidemiology of PCV3 in Shanxi Province.Our findings enabled us to assess the possibility of widespread transmission from this region.Thus,current findings establish a basis for further studies of genetic variations in PCV3 strains circulating in China.展开更多
Porcine circovirus 2 (PCV2) is currently considered an important etiologic agent of swine and its infection has potentially serious economic impact on the swine industry worldwide. This virus is frequently associated ...Porcine circovirus 2 (PCV2) is currently considered an important etiologic agent of swine and its infection has potentially serious economic impact on the swine industry worldwide. This virus is frequently associated with postweaning multisystemic wasting syndrome (PMWS), and also with other clinical conditions such as porcine dermatitis and nephropathy syndrome (PDNS), late-term abortions, reproductive failure in sows, proliferative and necrotizing pneumonia and congenital tremors. The term porcine circovirus-associated disease (PCVAD) is currently used to refer to any of these diseases when they are associated with PCV2 infection. The PCV2 was recognized as a pathogen in 1997, and many questions regarding its biology and pathogenesis remain unanswered. Currently, some studies have shown the production of new vaccine candidates and field efficacy testing of commercial vaccines. This review discusses some major points concerned with immunopathogenesis and vaccines for PCV2 infection.展开更多
Four species of porcine circoviruses(PCV1–4)have been reported to circulate in Chinese domestic pigs,while the epizootiology of these viruses in free-ranging wild boars in China remains unknown.In this study,tissue a...Four species of porcine circoviruses(PCV1–4)have been reported to circulate in Chinese domestic pigs,while the epizootiology of these viruses in free-ranging wild boars in China remains unknown.In this study,tissue and serum samples collected from diseased or apparently healthy wild boars between 2018 and 2020 in 19 regions of China were tested for the prevalence of PCV1–4 infections.Positive rates of PCV1,PCV2,and PCV3 DNA in the tissue samples of Chinese wild boars were 1.6%(4/247),58.3%(144/247),and 10.9%(27/247)respectively,with none positive for PCV4.Sequence analysis of viral genome showed that the four PCV1 strains distributed in Hunan and Inner Mongolia shared 97.5%–99.6%sequence identity with global distributed reference strains.Comparison of the ORF2 gene sequences showed that 80 PCV2 strains widely distributed in 18 regions shared 79.5%–100%sequence identity with reference strains from domestic pigs and wild boars,and were grouped into PCV2a(7),PCV2b(31)and PCV2d(42).For PCV3,17 sequenced strains shared 97.2%–100%nucleotide identity at the genomic level and could be divided into PCV3a(3),PCV3b(2)and PCV3c(12)based on the phylogeny of ORF2 gene sequences.Serological data revealed antibody positive rates against PCV1 and PCV2 of 11.4%(19/167)and 53.9%(90/167)respectively.The data obtained in this study improved our understanding about the epidemiological situations of PCVs infection in free-ranging wild boars in China and will be valuable for the prevention and control of diseases caused by PCVs infection.展开更多
In order to investigate infection and harm extent of swine porcine circovims 2 (PCV2) in pigs in Taizhou of Jiangsu, and to control the prevalence of PCV2 in Taizhou areas. A total of 116 PCV2 clinical samples came ...In order to investigate infection and harm extent of swine porcine circovims 2 (PCV2) in pigs in Taizhou of Jiangsu, and to control the prevalence of PCV2 in Taizhou areas. A total of 116 PCV2 clinical samples came from six different cities (districts) from 2011 to 2012 were tested in etiologic by the method of PCR. The test restdts showed that the total positive rate of PCV2 clinical samples was 53.45%, and PCV2 existed in all the six places. The positive rate of the scale pig farms was 48.33%, the positive rate of free-range farmers was 58.93%. Thus, PCV2 was prevalent in pigs in Taizhou areas, and which should be paid more attention to.展开更多
Porcine circovirus type 2(PCV2)is the main causative agent of porcine circovirus-associated diseases,and it causes substantial economic losses in the swine industry each year.It is crucial to develop an efective vacci...Porcine circovirus type 2(PCV2)is the main causative agent of porcine circovirus-associated diseases,and it causes substantial economic losses in the swine industry each year.It is crucial to develop an efective vaccine against the circulating strain PCV2d,which is prone to substantial degrees of mutation.In this study,a truncated form of fagellin(tFlic:85-111 aa)was inserted into the C-terminal sequence of 2dCap,and Western blotting results showed that recombinant Cap-tFlic VLPs were successfully expressed.Transmission electron microscopy(TEM)and dynamic light scattering(DLS)data indicated that purifed recombinant Cap-tFlic fusion proteins existed in the form of polymers and that tFlic could not afect the formation and internalization of VLPs.Integrated Cap-tFlic VLPs induced the expression of antigen presentation-related factors(MHC-II and CD86)by bone marrow-derived dendritic cells(BM-DCs),and the expression of TLR5-related factors(TNF-α)was dramatically elevated.Mice intramuscularly immunized with Cap-tFlic VLPs exhibited signifcantly higher levels of Cap-specifc antibodies and neutralizing antibodies than mice immunized with wild-type Cap VLPs.The data obtained in the current study indicate that Cap-tFlic may be a candidate for a subunit vaccine against PCV2 in the future.展开更多
基金This study was supported by a grant from the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Porcine circovirus type 2(PCV2),which serves as a major causative agent of PCV2-associated diseases and causes severe loss to the pig industry worldwide,can dysregulate the immune response and induce immunosuppression in PCV2-infected pigs.Similar to PCV2(porcine circovirus type 3(PCV3),a newly identified swine circovirus which might be closely associated with porcine dermatitis and nephropathy syndrome,reproductive disorder,and multisystemic inflammatoty responses,also interferes with host immune defense.Interaction between host immune system and PCVs is considered to be a crucial determinant of pathogenicity in pigs.Here,we sought to briefly discuss the current knowledge regarding the interaction of porcine circovirus type 2 and/or 3 with host immune cells and immune responses to better depict the viral immunomodulatory capacity,pathogenic mechanisms,and the future research direction in host immune responses to infection with PCV2 and PCV3.
基金funded by the Chinese Academy of Science Knowledge Innovation Project ( KZCX2-EW-QN411,Kscx2-Yw-N-051)the National Basic Research Program of China( 2009CB118800)
文摘Porcine cimovirus (PCV) is the smallest animal virus so far and has two serotypes. PCV1 is nonpathogenic, but PCV2 is pathogenic and causes post-weaning multisystemic wasting syndrome ( PMWS). Factors to induce PMWS include immunity and infection status of sows, infec- tion time, mixed infection, PCV2 variants, physical status of gilts, and feeding management. For final diagnosis, histopathological changes and ex- istence of PCV2 in lymphoid tissues are professional standards, because fluorescence quantitative RT-PCR is not enough specific or sensitive. The commemial PCV2 vaccines can reduce occurrence of PMWS and PCV-related diseases. This paper reviews recent advances in epidemiology of PCV2 as well as diagnosis and control of PMWS.
基金Supported by Natural Science Foundation of Hainan Province(Grant No.313100)
文摘[ Objective] This study aimed to investigate the molecular characteristics of porcine circovirus type 2 (PCV2) strains isolated from Hainan Province. [ Method] The complete genome of PCV2 was amplified from PMWS-suspected samples by PCR for sequence analysis. [ Result] A total of eight PCV2 strains were isolated and identified. All the eight isolates belonged to genotype PCV2b, among which seven isolates belonged to subgenotype PCV2b-1 C, and one isolate be- longed to subgenotype PCV2b-IA/1B. ORF2 gene of PCV2 isolates from Hainan Province was 705 bp in length, encoding 234 amino acids. Antigenic epitopes of Cap protein exhibited certain changes. Nucleotide sequences and deduced amino acid sequences of ORF2 gene shared 95.3% -99.7% and 93.6% - 100% simi- larities among eight PCV2 isolates from Hainan Province, respectively. Moreover, nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 91.0% -99.9% and 91.0% -99.6% similarities with other PCV2 strain isolated from China (AY682994, AF381175, JX945577, JX682407, AY180397 ), respectively; nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 90.0% - 97.0% and 88.0% -97.9% similarities with PCV2 isolates from other countries ( NC_005148, JQ994268, KJ187306, AF201307, AF454546, AY"/Sd020), respectively; nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 98.2% -100% and 94.9% -100% similarities with vaccine strain SH, respectively; nucleotide sequences and deduced amino acid sequences of ORF2 gene of PCV2 isolates from Hainan Province shared 90.6% -91.7% and 89.7% - 91.0% similarities with vaccine strain LG, respectively. [ Conclusion] This study provided theoretical hasis for the prevention and control of PCV2 and selection of vaccine strains in Hainan Province.
基金Supported by Young and Middle-Aged Scientists Research Awards Fund of Shangdong Province(BS2011SW026)
文摘The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein (EGFP) report gene. ORF2 gene of porcine circovirus type 2 cloned by PCR was ligated to the expression vector pEGFP-N1, which contains enhanced green fluorescent protein (EGFP) report gene, the recombinant eukaryotic expression plasmid pEGFP-N1-ORF2 was constructed successfully and was transfected into pre- pared duck myocardial cells (DMCs) by lipofectin. According to the result, the fluorescence expression was directly detected with fluorescence microscope, and the expression of ORF2 were analyzed by RT-PCR and indirect immunofluorescence assay (IFA) respectively. About 48 h after transfection, green fluorescent can be observed on transfected cells : T-PCR and IFA were positive. This indicated that ORF2 gene of PCV2 was expressed efficiently in transfected duck myocardial cells.
文摘Porcine cimovirus type 2 (PCV2) infection causes huge economic losses, but no serological method is available for batch detection of field samples. The aim of the study was to develop a method for large-batch detection of PCV2 infection. Colloidal gold-labeled staphylococcal protein A (SPA) was sprayed on glass fibers to prepare a conjugate pad. The recombinant ORF2 protein of PCV2 was blotted on the test line of the nitrocellulose (NC) membrane, and pig IgG was streaked on the control line of the NC membrane. Then, the immunochromatographic strip was used for detection of antibodies against PCV2. The results show that the strip test was simple and the results could be determined within 10 min with naked eyes. The test strip was highly specific for pig serum against PCV2 and no cross-reaction with pig serum against other pathogens was observed. The test strip had close similarity with ELISA. Storage at RT for 6 months did not affect the specificity and sensitivity obviously. A total of 324 clinical pig sera were detected by both ELISA and the developed test strip, and the coincidence was 98.77%. Therefore, the developed immunochromatographic strip is specific, sensitive, stable, fast and simple, and it is suitable for on-site detection of antibodies against PCV2.
基金supported by the Chengdu Science and Technology Bureau
文摘[ Objective] The study aimed to analyze the prevalence of Porcine Parvovirus (PPV) and Porcine Circovirus Type 2 ( PCV2 ) and the mixed infection in Sichuan Province to lay the foundation for further predicting the tendency of the plague and formulating appropriate prevention and control strategies. [ Method] Two hundred and seventy -three samples were collected from 21 large pig farms in Sichuan province, and epidemiology of PPV and PCV2 were investigated by PCR detecting. [ Result] The positive rate of PPV was 17.22% (47/273), and positive rate of pig farms was 38.1% (8/21), meanwhile it also displayed the feature that infection rate of boar was higher than that of piglets; The positive rate of PCV2 was 52.38% (143/273), and positive rate of pig farms was 85.7% (18/21), and it showed the trend that the infection rate of PCV2 was rising with the growth of the age. The co-infection rate of PPV and PCV2 was 10.62% (29/273), and co-infection rate of pig farms was 28.7% (6/21), which mainly concentrated in the sow and nursery piglets. Only 14.3% (3/21) pig farms was epidemiologically negative of PPV and PCV2. [ Conclusion] PPV and PCV2 and co-infection was widely popular in Sichuan province, and it did more serious harm to the pig-raising industry.
基金Supported by Shandong Province Natural Science Fund Project
文摘[ Objective ] To establish a real-time fluorescent quantitative polymerase chain reaction (PCR) method with SYBR Green I for the detection of porcine circovirus type 2 (PCV2). [Methods] Specific primers were designed to amplify the conserved gene segments of PCV2 with a size of 177 bp by PCR. The ampli- fied gene was cloned into the vector of pMD 18-T and transformed into DHSct to screen positive clones. After being extracted and purified, the recombinant plasraids pMD 18-T-177 were taken as the standard DNA templates to establish the fluorescence quantitative PCR method for the detection of PCV2, and the PCR re- action conditions were optimized. [ Results] Ct value of the established PCR method showed a good linear relationship with the standard DNA templates within a viral load of 3.21 × 100 -4.16 × 108 copies/μL , the correlation coefficient was O. 998 8 and the slope was - 3.286. The method did not show any cress-reactions with the genomes of PRRSV, PCV1, CSFV, PRV, PPV and Escherichia coli. Sensitivity of this method was proved to be 3.21 × 10 copies/μL, which was 1 000 times higher as conventional PCR method. Variation coefficients of the repeated trims among same batch or different batches were both less than 3.00%. Positive rate of clinical samples detected by the established PCR method was 58.94%, which was significantly higher than the detection rate by conventional PCR. [ Conclusions ] A reM-time fluorescent quantitative PCR method with SYBR Green I for the detection of PCV2 was established, which was better for conducting the quan- titative analysis and the early diagnosis of PCV2 infection.
基金Supported by the National Key R&D Program of China(2016YFD0501105,2016YFD0501106)
文摘The development history, etiology, epidemiology, clinical symptoms, pathological changes and diagnosis technology of porcine circovirus 3 were summarized, and countermeasures for prevention and control of the disease were put forward based on the prevalence status in China.
基金Supported by Key Project of Jiangsu Agri-animal Husbandry Vocational College(ZD201104)College Students'Innovation and Enterpreneurship Training Program of Jiangsu Province(201312806014Y)Special Fund for Fenghuang talents in Jiangsu Agri-animal Husbandry Vocational College
文摘In September 2011, an infectious disease suspected to be postweaning multisystemic wasting syndrome (PMWS) broke out in some pig farm in Taizhou. The inguinal lymph node, liver and lung tissues were collected and grinded into tissue suspension. The suspension was subjected to PCR detection, and the positive product was sequenced. The suspension of positive samples was filtered with 0.22 μm filter membrane, and the filtrate was inoculated onto PK15 cells. After five generations of blind passages, the cell viral liquid was collected and extracted for DNA, which was subjected to PCR detection and indirect immunofluorescence. The results showed that the isolate was porcine circovirus type 2 (PCV2) and designated as TAIZ110926. The target sequence was committed to NCBI with a serial number: KF039888.
基金Supported by Shandong Province Natural Science Foundation of China(ZR2013CQ006)
文摘In order to obtain induction expressed porcine circovirus type 2(PCV2)multi-epitope with good immunogenicity in vitro.Major epitopes of PCV2 were screened in the test,epitopes were composed sequentially,the c DNA sequences were artificially synthesized.Bam HⅠand SalⅠwere directionally cloned into prokaryotic expression vector PEGX-4T-1 multiple cloning site,then BL21 competent cells were transformed,positive clones were screened,IPTG inducible expression was conducted.Expression on target gene was analyzed by SDS-PAGE,fusion protein polypeptide was extracted and purified,immunocompetence of the expressed multi-epitope protein was identified by Westernblot.BALB/c mouse was immuned by fusion protein polypeptide,the antibody was determined by ELISA,immunogenicity was evaluated.Results showed that expression recombinant plasmid pEGX-4T-1-ep contained with seven PCV2 antigen epitopes had been constructed successfully.SDS-PAGE analysis showed that fusion protein polypeptide was expressed effectively in Escherichia coli(E.coli),and the molecular weight was about 35ku,which existed in the form of solubility.Results of Westernblot showed that the extraction and purification of fusion protein polypeptide and PCV2 positive serum had good reactogenicity.Results of ELISA showed that the purified fusion protein polypeptide could stimulate the body to produce PCV2 specific antibody which had good immunogenicity.Results indicated that the constructed PCV2 multi-epitope had good expression characteristics in vitro,and the expression protein had good immunogenicity.The study provided a basic for the study on PCV2 epitope screening,functional identification and multi-epitope vaccine.
基金This research was supported by funding from the Key Research and Development Projea Key Program of Shanxi Province,China(grant no.201703D211001).
文摘Porcine circovirus type 3(PCV3),which was first detected in the United States of America in 2015,is a potential threat to the swine industry.However,the prevalence of PCV3 in Shanxi Province,China,is unclear.In this research,the prevalence and genetic diversity of PCV3 were investigated in above area.Lung tissue samples(n=491)from 19 pig slaughterhouses across 11 cities throughout Shanxi Province were analyzed for PCV3 infection by PCR in 2019.The results showed that PCV3 positive rates in slaughterhouses and individuals were 100%(19/19)and 86.76%(426/491),respectively.PCV2 and PCV3 double-positive rates in slaughterhouses and individuals were 100%(19/19)and 59.27%(291/491),respectively.PCR positive samples were further sequenced and 8 PCV3 isolates were identified.The nucleotide homology of these isolates with other PCV3 isolates in NCBI database was 97.45-99.90%.A phylogenetic analysis,based on the complete genomic sequence and ORF2,divided these PCV3 strains into 2 major groups.Based on A24A/and R27/K amino acid mutations of capsid protein,the 8 identified PCV3 strains were separated to 2 clades.This was the first detailed investigation into the epidemiology of PCV3 in Shanxi Province.Our findings enabled us to assess the possibility of widespread transmission from this region.Thus,current findings establish a basis for further studies of genetic variations in PCV3 strains circulating in China.
基金The FAPEMIG and CNPq project financial support is from production of vaccines against PCV2 group studying.
文摘Porcine circovirus 2 (PCV2) is currently considered an important etiologic agent of swine and its infection has potentially serious economic impact on the swine industry worldwide. This virus is frequently associated with postweaning multisystemic wasting syndrome (PMWS), and also with other clinical conditions such as porcine dermatitis and nephropathy syndrome (PDNS), late-term abortions, reproductive failure in sows, proliferative and necrotizing pneumonia and congenital tremors. The term porcine circovirus-associated disease (PCVAD) is currently used to refer to any of these diseases when they are associated with PCV2 infection. The PCV2 was recognized as a pathogen in 1997, and many questions regarding its biology and pathogenesis remain unanswered. Currently, some studies have shown the production of new vaccine candidates and field efficacy testing of commercial vaccines. This review discusses some major points concerned with immunopathogenesis and vaccines for PCV2 infection.
基金This work was supported by grants from the National Natural Science Foundation of China to Z Tu(31902307)National Key Research and Development Program of China to C Tu(2017YFD0500104)Wildlife Borne Infectious Diseases Monitoring Project of the State Forestry and Grassland Administration of China.
文摘Four species of porcine circoviruses(PCV1–4)have been reported to circulate in Chinese domestic pigs,while the epizootiology of these viruses in free-ranging wild boars in China remains unknown.In this study,tissue and serum samples collected from diseased or apparently healthy wild boars between 2018 and 2020 in 19 regions of China were tested for the prevalence of PCV1–4 infections.Positive rates of PCV1,PCV2,and PCV3 DNA in the tissue samples of Chinese wild boars were 1.6%(4/247),58.3%(144/247),and 10.9%(27/247)respectively,with none positive for PCV4.Sequence analysis of viral genome showed that the four PCV1 strains distributed in Hunan and Inner Mongolia shared 97.5%–99.6%sequence identity with global distributed reference strains.Comparison of the ORF2 gene sequences showed that 80 PCV2 strains widely distributed in 18 regions shared 79.5%–100%sequence identity with reference strains from domestic pigs and wild boars,and were grouped into PCV2a(7),PCV2b(31)and PCV2d(42).For PCV3,17 sequenced strains shared 97.2%–100%nucleotide identity at the genomic level and could be divided into PCV3a(3),PCV3b(2)and PCV3c(12)based on the phylogeny of ORF2 gene sequences.Serological data revealed antibody positive rates against PCV1 and PCV2 of 11.4%(19/167)and 53.9%(90/167)respectively.The data obtained in this study improved our understanding about the epidemiological situations of PCVs infection in free-ranging wild boars in China and will be valuable for the prevention and control of diseases caused by PCVs infection.
基金Supported by the Key Topics of Jiangsu Animal Husbandry and Veterinary College(ZD201104)Science and Technology Pillar(Agriculture)Program of Taizhou City
文摘In order to investigate infection and harm extent of swine porcine circovims 2 (PCV2) in pigs in Taizhou of Jiangsu, and to control the prevalence of PCV2 in Taizhou areas. A total of 116 PCV2 clinical samples came from six different cities (districts) from 2011 to 2012 were tested in etiologic by the method of PCR. The test restdts showed that the total positive rate of PCV2 clinical samples was 53.45%, and PCV2 existed in all the six places. The positive rate of the scale pig farms was 48.33%, the positive rate of free-range farmers was 58.93%. Thus, PCV2 was prevalent in pigs in Taizhou areas, and which should be paid more attention to.
基金This work was supported by the Key Laboratory of Veterinary Biological Products and Chemicals,Ministry of Agriculture,China Animal Husbandry Industry Co.,Ltd.Project name:Novel Adjuvanted Chimeric Porcine Circovirus Type 2 CAP Virus-Like Particle Vaccine and project number:20201612(2020-2024).
文摘Porcine circovirus type 2(PCV2)is the main causative agent of porcine circovirus-associated diseases,and it causes substantial economic losses in the swine industry each year.It is crucial to develop an efective vaccine against the circulating strain PCV2d,which is prone to substantial degrees of mutation.In this study,a truncated form of fagellin(tFlic:85-111 aa)was inserted into the C-terminal sequence of 2dCap,and Western blotting results showed that recombinant Cap-tFlic VLPs were successfully expressed.Transmission electron microscopy(TEM)and dynamic light scattering(DLS)data indicated that purifed recombinant Cap-tFlic fusion proteins existed in the form of polymers and that tFlic could not afect the formation and internalization of VLPs.Integrated Cap-tFlic VLPs induced the expression of antigen presentation-related factors(MHC-II and CD86)by bone marrow-derived dendritic cells(BM-DCs),and the expression of TLR5-related factors(TNF-α)was dramatically elevated.Mice intramuscularly immunized with Cap-tFlic VLPs exhibited signifcantly higher levels of Cap-specifc antibodies and neutralizing antibodies than mice immunized with wild-type Cap VLPs.The data obtained in the current study indicate that Cap-tFlic may be a candidate for a subunit vaccine against PCV2 in the future.