NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-l...NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-like PRRSV evolved,named the L1A variant.The phylogenetics,epidemic status,and pathogenicity of the LA variants were subsequently comprehensively evaluated.Based on the results of the ORF5 phylogenetic analysis,the L1A variants were classified as NADC34-like PPRSV.All the strains had the same discontinuous 131-aa deletion in the NSP2 region(similar to that in the NADC30).Recombination analysis revealed that the L1A variants were recombinant viruses that contained an NADC30-like PRRSV skeleton,a nonstructural protein-encoding gene region obtained in part from JXA1-like PRRSV and a ORF2-ORF6 gene region partly obtained from NADC34-like PRRSV and that exhibited similar recombination patterns.We successfully isolated the L1A variant TZJ2756 from PAMs and Marc-145 cells.In animal experiments,TZJ2756 exhibited moderate pathogenicity in piglets,causing obvious clinical symptoms,namely,persistent fever,significantly reduced body weight,interstitial edema and severe interstitial pneumonia in the lungs,and prolonged high-load viremia.L1A variants have been detected in at least 12 provinces in China and share many similar epidemiological characteristics with the American L1C variant.This research will enhance our understanding of the prevalence of L1A variants and furnish valuable data for the ongoing monitoring of NADC34-like PRRSV in China.展开更多
Dear Editor,The highly pathogenic avian influenza viruses(HPAIVs)are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and ...Dear Editor,The highly pathogenic avian influenza viruses(HPAIVs)are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and public health.Wild birds have been recognized as the primary reservoirs for influenza A virus,and some species show little sign of clinical disease or even can be asymptomatic during long distance carriers of the virus(Lycett et al.,2019).Since it was first discovered in 1959,the H5Nx HPAIVs have spread globally and cause outbreaks in wild birds,poultry and sporadic human and other mammalian infections(Lycett et al.,2019).Due to the reassortant events of diverse strains facilitated by migratory waterfowl,the clade 2.3.4.4 of H5Nx viruses acquiring neuraminidase(NA)gene from other low pathogenicity avian influenza viruses(LPAIVs)emerged in 2014 and gradually became the dominant sub-clade(Lee et al.,2017).展开更多
Currently, various porcine reproductive and respiratory syndrome virus(PRRSV) variants emerged worldwide with different genetic characteristics and pathogenicity, increasing the difficulty of PRRS control. In this stu...Currently, various porcine reproductive and respiratory syndrome virus(PRRSV) variants emerged worldwide with different genetic characteristics and pathogenicity, increasing the difficulty of PRRS control. In this study, a PRRSV strain named HBap4-2018 was isolated from swine herds suffering severe respiratory disease with high morbidity in Hebei Province of China in 2018. The genome of HBap4-2018 is 15,003 nucleotides in length, and compared with NADC30-like PRRSV, nsp2 of HBap4-2018 has an additional continuous deletion of five amino acids. Phylogenetic analysis based on complete genome and ORF5 showed that HBap4-2018 belonged to lineage 8 of PRRSV-2, which was characterized by highly variable genome. However, HBap4-2018 was classified into lineage 1 based on phylogenetic analysis of nsp2,sharing higher amino acid homology(85.3%–85.5%) with NADC30-like PRRSV. Further analysis suggested that HBap4-2018 was a novel natural recombinant PRRSV with three recombinant fragments in the genome, of which highly pathogenic PRRSV(HP-PRRSV) served as the major parental strains, while NADC30-like PRRSV served as the minor parental strains. Five recombination break points were identified in nsp2, nsp3, nsp5, nsp9 and ORF6, respectively,presenting a novel recombinant pattern in the genome. Piglets inoculated with HBap4-2018 presented typical clinical signs with a mortality rate of 60%. High levels of viremia and obvious macroscopic and histopathological lesions in the lungs were observed, revealing the high pathogenicity of HBap4-2018 in piglets.展开更多
[Objective] To identify suspected cases of highly pathogenic PRRSV from a pig farm. [Method] The suspected cases of highly pathogenic PRRSV were conducted pathologic anatomy, the gene of PRRSV N protein was amplified ...[Objective] To identify suspected cases of highly pathogenic PRRSV from a pig farm. [Method] The suspected cases of highly pathogenic PRRSV were conducted pathologic anatomy, the gene of PRRSV N protein was amplified by RT-PCR and its sequences were determined and analyzed. [Result] The nucleotide sequence of N protein of N7/N8 isolate shared the consistency of 97.0% with highly pathogenic strains （JXA1, HUN4, SX-1 and TJ）, and that of isolate N9 shared the consistency of 97.3% with highly pathogenic strains, indicating the infected virus in the pig farm was highly pathogenic PRRSV. [Conclusion] This research provides a reference for the diagnosis of highly pathogenic PRRSV infec- tion in swine production.展开更多
A novel Clade 2.3.2.1c H5N1 reassortant virus caused several outbreaks in wild birds in some regions of China from late 2014 to 2015.Based on the genetic and phylogenetic analyses,the viruses possess a stable gene con...A novel Clade 2.3.2.1c H5N1 reassortant virus caused several outbreaks in wild birds in some regions of China from late 2014 to 2015.Based on the genetic and phylogenetic analyses,the viruses possess a stable gene constellation with a Clade 2.3.2.1c HA,a H9N2-derived PB2 gene and the other six genes of Asian H5N1-origin.The Clade 2.3.2.1c H5N1 reassortants displayed a high genetic relationship to a human H5N1 strain(A/Alberta/01/2014).Further analysis showed that similar viruses have been circulating in wild birds in China,Russia,Dubai(Western Asia),Bulgaria and Romania(Europe),as well as domestic poultry in some regions of Africa.The affected areas include the Central Asian,East Asian-Australasian,West Asian-East African,and Black Sea/Mediterranean flyways.These results show that the novel Clade 2.3.2.1c reassortant viruses are circulating worldwide and may have gained a selective advantage in migratory birds,thus posing a serious threat to wild birds and potentially humans.展开更多
Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic ...Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China＇s pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses （3×103-3×105 TCID50）.The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever （41.0-41.9oC） and high morbidity and mortality （60-100%）,the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection （DPI）.The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.展开更多
The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and a...The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and antibody levels,the epidemic prevention effect of HP-PRRS in Changping District was scientifically assessed.展开更多
In 2013, a human influenza outbreak caused by a novel H7N9 virus occurred in China. Recently, the H7N9 virus acquired multiple basic amino acids at its hemagglutinin（HA） cleavage site, leading to the emergence of a ...In 2013, a human influenza outbreak caused by a novel H7N9 virus occurred in China. Recently, the H7N9 virus acquired multiple basic amino acids at its hemagglutinin（HA） cleavage site, leading to the emergence of a highly pathogenic virus. The development of an effective diagnostic method is imperative for the prevention and control of highly pathogenic H7N9 influenza. Here, we designed and synthesized three pairs of primers based on the nucleotide sequence at the HA cleavage site of the newly emerged highly pathogenic H7N9 influenza virus. One of the primer pairs and the corresponding probe displayed a high level of amplification efficiency on which a real-time RT-PCR method was established. Amplification using this method resulted in a fluorescent signal for only the highly pathogenic H7N9 virus, and not for any of the H1–H15 subtype reference strains, thus demonstrating high specificity. The method detected as low as 39.1 copies of HA-positive plasmid and exhibited similar sensitivity to the virus isolation method using embryonated chicken eggs. Importantly, the real-time RT-PCR method exhibited 100% consistency with the virus isolation method in the diagnosis of field samples. Collectively, our data demonstrate that this real-time RT-PCR assay is a rapid, sensitive and specific method, and the application will greatly aid the surveillance, prevention, and control of highly pathogenic H7N9 influenza viruses.展开更多
Background： Porcine reproductive and respiratory syndrome virus （PRRSV）, and particularly its highly pathogenic genotype （HP-PRRSV）, have caused massive economic losses to the global swine industry. Results： To ...Background： Porcine reproductive and respiratory syndrome virus （PRRSV）, and particularly its highly pathogenic genotype （HP-PRRSV）, have caused massive economic losses to the global swine industry. Results： To rapidly identify HP-PRRSV, we developed a direct reaL-time reverse transcription polymerase chain reaction method （dRT-PCR） that could detect the virus from serum specimen without the need of RNA purification Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result. Additionally, the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR （cRT-PCR） that used purified RNA The lowest detection limit of HP-PRRSV was 6.3 TCIDs0 using dRT-PCR. We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR. Moreover, the dRT-PCR method was able to tolerate 5-20% （v/v） serum. Conclusions： Our dRT-PCR assay allows for easier, faster, more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods. To the best of our knowledge, this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA. We believe our approach has a great potential for application to other RNA viruses.展开更多
The stamping-out strategy has been used to control highly pathogenic avian influenza viruses in many countries,driven by the belief that vaccination would not be successful against such viruses and fears that avian in...The stamping-out strategy has been used to control highly pathogenic avian influenza viruses in many countries,driven by the belief that vaccination would not be successful against such viruses and fears that avian influenza virus in vaccinated birds would evolve more rapidly and pose a greater risk to humans.In this review,we summarize the successes in controlling highly pathogenic avian influenza in China and make suggestions regarding the requirements for vaccine selection and effectiveness.In addition,we present evidence that vaccination of poultry not only eliminates human infection with avian influenza virus,but also significantly reduces and abolishes some harmful characteristics of avian influenza virus.展开更多
Objective In China, 24 cases of human infection with highly pathogenic avian influenza(HPAI) H5 N6 virus have been confirmed since the first confirmed case in 2014. Therefore, we developed and assessed two H5 N6 candi...Objective In China, 24 cases of human infection with highly pathogenic avian influenza(HPAI) H5 N6 virus have been confirmed since the first confirmed case in 2014. Therefore, we developed and assessed two H5 N6 candidate vaccine viruses(CVVs).Methods In accordance with the World Health Organization(WHO) recommendations, we constructed two reassortant viruses using reverse genetics(RG) technology to match the two different epidemic H5 N6 viruses. We performed complete genome sequencing to determine the genetic stability. We assessed the growth ability of the studied viruses in MDCK cells and conducted a hemagglutination inhibition assay to analyze their antigenicity. Pathogenicity attenuation was also evaluated in vitro and in vivo.Results The results showed that no mutations occurred in hemagglutinin or neuraminidase, and both CVVs retained their original antigenicity. The replication capacity of the two CVVs reached a level similar to that of A/Puerto Rico/8/34 in MDCK cells. The two CVVs showed low pathogenicity in vitro and in vivo, which are in line with the WHO requirements for CVVs.Conclusion We obtained two genetically stable CVVs of HPAI H5N6 with high growth characteristics,which may aid in our preparedness for a potential H5N6 pandemic.展开更多
Since mid-2016,the low pathogenic H7N9 influenza virus has evolved into a highly pathogenic(HP)phenotype in China,raising many concerns about public health and poultry industry.The insertion of a“KRTA”motif at hemag...Since mid-2016,the low pathogenic H7N9 influenza virus has evolved into a highly pathogenic(HP)phenotype in China,raising many concerns about public health and poultry industry.The insertion of a“KRTA”motif at hemagglutinin cleavage site(HACS)occurred in the early stage of HP H7N9 variants.During the co-circulation,the HACS of HP-H7N9 variants were more polymorphic in birds and humans.Although HP-H7N9 variants,unlike the H5 subtype virus,exhibited the insertions of basic and non-basic amino acids,the underlying function of those insertions and substitutions remains unclear.The results of bioinformatics analysis indicated that the PEVPKRKRTAR/G motif of HACS had become the dominant motif in China.Then,we generated six H7N9 viruses bearing the PEIPKGR/G,PEVPKGR/G,PEVPKRKRTAR/G,PEVPKGKRTAR/G,PEVPKGKRIAR/G,and PEVPKRKRR/G motifs.Interestingly,after the deletion of threonine and alanine(TA)at HACS,the H7N9 viruses manifested decreased thermostability and virulence in mice,and the PEVPKRKRTAR/G-motif virus is prevalent in birds and humans probably due to its increased transmissibility and moderate virulence.By contrast,the insertion of non-basic amino acid isoleucine and alanine(IA)decreased the transmissibility in chickens and virulence in mice.Remarkably,the I335V substitution of H7N9 virus enhanced infectivity and transmission in chickens,suggesting that the combination of mutations and insertions of amino acids at the HACS promoted replication and pathogenicity in chickens and mice.The ongoing evolution of H7N9 increasingly threatens public health and poultry industry,so,its comprehensive surveillance and prevention of H7N9 viruses should be pursued.展开更多
Porcine reproductive and respiratory syndrome virus(PRRSV) has been mutating and evolving constantly since its emergence in the1980s, which has brought inestimable economic losses to the global swine industry. The vir...Porcine reproductive and respiratory syndrome virus(PRRSV) has been mutating and evolving constantly since its emergence in the1980s, which has brought inestimable economic losses to the global swine industry. The virus has two genotypes, of which genotype 1 PRRSV(PRRSV 1) first broke out in Germany and mainly prevailed in Europe, which can be clustered into four subtypes based on the ORF5 sequence. Al-though few cases of PRRSV 1 have been reported in China, the prevention and control of PRRSV should not be ignored. The origin of PRRSV, ge-netic evolution and pathogenicity of PRRSV 1 were retrospectively analyzed, in order to provide valuable evidences for molecular epidemiology and immune prevention and control of PRRSV 1.展开更多
At the present stage, the social economy in China has developed by leaps and bounds. China's pig industry has been well developed un-der the background of this era. However, the number of pig diseases increases du...At the present stage, the social economy in China has developed by leaps and bounds. China's pig industry has been well developed un-der the background of this era. However, the number of pig diseases increases due to the influence of many factors, and highly pathogenic porcine reproductive and respiratory syndrome(HP-PRRS) is one of the very common diseases, causing growing mortality rate of pigs. The disease increases the economic loss of pig industry to a large extent, and brings difficulties in prevention and control of pig diseases. The staff must analyze and sum-marize the basic characteristics of pig diseases, and combine some practical problems in prevention and control of pig disease to find effective mea-sures. The scope and scale of pig production in different parts of China have been continuously expanded under the background of further develop-ment of pig industry in the new era. But for pig production, pig disease has been a problem that delays its further development. Related personnel must analyze and summarize the status quo of HP-PRRS, to find effective prevention measures and strategy.展开更多
The study was designed to evaluate the level of knowledge of Nigerian Veterinary Laboratory Staff on the nature of Highly Pathogenic Avian Influenza (HPAI) disease using structured questionnaires. The study comprised ...The study was designed to evaluate the level of knowledge of Nigerian Veterinary Laboratory Staff on the nature of Highly Pathogenic Avian Influenza (HPAI) disease using structured questionnaires. The study comprised the Staff of National Veterinary Research Institute (NVRI) and five reference Veterinary Teaching Hospitals (VTH) designated for HPAI diagnosis. A total of 69 questionnaires were distributed to the laboratory staff. Questions on the general nature of the disease such as the cause, signs, mode of transmission, methods of identification, lesions, control and prevention, etc. were asked. The results showed that 77.38% of the staff answered all the questions correctly indicating their considerable knowledge of the HPAI disease. Considerable percentage of the staff listed correctly the equipment used for serology (36.23%) and RT-PCR (31.88%). Interestingly only 13.04% of the staff listed correctly the equipment used in rapid tests despite the fact that they are simpler and recommended for all P2 laboratories. In conclusion, the veterinary laboratory staff assessed demonstrated a significant level of knowledge on HPAI diagnosis;however, most of their laboratories lack the structure, organization, funds and basic facilities required for effective HPAI diagnosis.展开更多
To evaluate the risk of highly pathogenic avian influenza （HPAI） in China's Mainland, a risk assessment framework was built. Risk factors were determined by analyzing the epidemic data using the brainstorming me...To evaluate the risk of highly pathogenic avian influenza （HPAI） in China's Mainland, a risk assessment framework was built. Risk factors were determined by analyzing the epidemic data using the brainstorming method; the analytic hierarchy process was designed to weigh risk factors, and the integrated multicriteria analysis was used to evaluate the final result. The completed framework included the risk factor system, data standards for risk factors, weights of risk factors, and integrated assessment methods. This risk assessment framework can be used to quantitatively analyze the outbreak and spread of HPAI in China's Mainland.展开更多
The highly pathogenic avian influenza （HPAI） H5N1 virus has caused several outbreaks in domestic poultry. Despite great efforts to control the spread of this virus, it continues to evolve and poses a substantial thr...The highly pathogenic avian influenza （HPAI） H5N1 virus has caused several outbreaks in domestic poultry. Despite great efforts to control the spread of this virus, it continues to evolve and poses a substantial threat to public health because of a high mortality rate. In this study, we sequenced whole genomes of eight H5N1 avian influenza viruses isolated from domestic poultry in eastern China and compared them with those of typical influenza virus strains. Phylogenetic analyses showed that all eight genomes belonged to clade 2.3.2.1 and clade 7.2, the two main circulating clades in China. Viruses that clustered in clade 2.3.2.1 shared a high degree of homology with H5N1 isolates located in eastern Asian. Isolates that clustered in clade 7.2 were found to circulate throughout China, with an east-to-west density gradient. Pathogenicity studies in mice showed that these isolates replicate in the lungs, and clade 2.3.2.1 viruses exhibit a notably higher degree of virulence compared to clade 7.2 viruses. Our results contribute to the elucidation of the biological characterization and pathogenicity of HPAI H5N1 viruses.展开更多
基金supported by grants from the National Natural Science Foundation of China(32172890 and 32002315)the National Key Research and Development Program of China(2022YFF0711004)+3 种基金the Natural Science Foundation of Heilongjiang Province,China(YQ2022C042)the State Key Laboratory of Veterinary Biotechnology Foundation of China(SKLVBF202208)the Postdoctoral Fellowship Program of CPSF,China(GZC20233062)the National Center of Technology Innovation for Pigs,China(NCTIP-XD/C09)。
文摘NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-like PRRSV evolved,named the L1A variant.The phylogenetics,epidemic status,and pathogenicity of the LA variants were subsequently comprehensively evaluated.Based on the results of the ORF5 phylogenetic analysis,the L1A variants were classified as NADC34-like PPRSV.All the strains had the same discontinuous 131-aa deletion in the NSP2 region(similar to that in the NADC30).Recombination analysis revealed that the L1A variants were recombinant viruses that contained an NADC30-like PRRSV skeleton,a nonstructural protein-encoding gene region obtained in part from JXA1-like PRRSV and a ORF2-ORF6 gene region partly obtained from NADC34-like PRRSV and that exhibited similar recombination patterns.We successfully isolated the L1A variant TZJ2756 from PAMs and Marc-145 cells.In animal experiments,TZJ2756 exhibited moderate pathogenicity in piglets,causing obvious clinical symptoms,namely,persistent fever,significantly reduced body weight,interstitial edema and severe interstitial pneumonia in the lungs,and prolonged high-load viremia.L1A variants have been detected in at least 12 provinces in China and share many similar epidemiological characteristics with the American L1C variant.This research will enhance our understanding of the prevalence of L1A variants and furnish valuable data for the ongoing monitoring of NADC34-like PRRSV in China.
基金supported by Zhejiang Province Science and Technology Cooperation Project of“Three Rural and Nine Parties”(grant number 2023SNJF059).
文摘Dear Editor,The highly pathogenic avian influenza viruses(HPAIVs)are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and public health.Wild birds have been recognized as the primary reservoirs for influenza A virus,and some species show little sign of clinical disease or even can be asymptomatic during long distance carriers of the virus(Lycett et al.,2019).Since it was first discovered in 1959,the H5Nx HPAIVs have spread globally and cause outbreaks in wild birds,poultry and sporadic human and other mammalian infections(Lycett et al.,2019).Due to the reassortant events of diverse strains facilitated by migratory waterfowl,the clade 2.3.4.4 of H5Nx viruses acquiring neuraminidase(NA)gene from other low pathogenicity avian influenza viruses(LPAIVs)emerged in 2014 and gradually became the dominant sub-clade(Lee et al.,2017).
基金The siudy was supported by the Shanghai Municipal Agriculture Science and Technology Project(2020-02-0800-08-F01465)the National Natural Science Foundation of China(32072861)+1 种基金the Natural Science Foundation of Shanghai(20ZR1469600)the earmarked fund for Modern Agro-industry Technology Research System of China(CARS-35)。
文摘Currently, various porcine reproductive and respiratory syndrome virus(PRRSV) variants emerged worldwide with different genetic characteristics and pathogenicity, increasing the difficulty of PRRS control. In this study, a PRRSV strain named HBap4-2018 was isolated from swine herds suffering severe respiratory disease with high morbidity in Hebei Province of China in 2018. The genome of HBap4-2018 is 15,003 nucleotides in length, and compared with NADC30-like PRRSV, nsp2 of HBap4-2018 has an additional continuous deletion of five amino acids. Phylogenetic analysis based on complete genome and ORF5 showed that HBap4-2018 belonged to lineage 8 of PRRSV-2, which was characterized by highly variable genome. However, HBap4-2018 was classified into lineage 1 based on phylogenetic analysis of nsp2,sharing higher amino acid homology(85.3%–85.5%) with NADC30-like PRRSV. Further analysis suggested that HBap4-2018 was a novel natural recombinant PRRSV with three recombinant fragments in the genome, of which highly pathogenic PRRSV(HP-PRRSV) served as the major parental strains, while NADC30-like PRRSV served as the minor parental strains. Five recombination break points were identified in nsp2, nsp3, nsp5, nsp9 and ORF6, respectively,presenting a novel recombinant pattern in the genome. Piglets inoculated with HBap4-2018 presented typical clinical signs with a mortality rate of 60%. High levels of viremia and obvious macroscopic and histopathological lesions in the lungs were observed, revealing the high pathogenicity of HBap4-2018 in piglets.
基金Supported by National Natural Science Foundation of China(31572550)Agricultural Industry Re-search System of Shandong Province(SDAIT-06-022-06)+1 种基金Major Scientific and Technological Achievements Training Program of Shandong Academy of Agricultural Sciences(2014CGPY04)Project of Taishan Scholar
文摘[Objective] To identify suspected cases of highly pathogenic PRRSV from a pig farm. [Method] The suspected cases of highly pathogenic PRRSV were conducted pathologic anatomy, the gene of PRRSV N protein was amplified by RT-PCR and its sequences were determined and analyzed. [Result] The nucleotide sequence of N protein of N7/N8 isolate shared the consistency of 97.0% with highly pathogenic strains （JXA1, HUN4, SX-1 and TJ）, and that of isolate N9 shared the consistency of 97.3% with highly pathogenic strains, indicating the infected virus in the pig farm was highly pathogenic PRRSV. [Conclusion] This research provides a reference for the diagnosis of highly pathogenic PRRSV infec- tion in swine production.
基金supported by grants from the National Natural Science Foundation of China (31311120063,81470096,31570026,31471253)the Ministry of Education and Science of the Russian Federation (Chinese-Russian project:RFMEFI61315X0045)+3 种基金the intramural special grant for influenza virus research from the Chinese Academy of Sciences (KJZD-EW-L09)the IDRCAPEIR program (106915-001)Special Project of Ministry of Science and Technology (2013FY113500)supported by the “Taishan Scholar” project of Shandong Province
文摘A novel Clade 2.3.2.1c H5N1 reassortant virus caused several outbreaks in wild birds in some regions of China from late 2014 to 2015.Based on the genetic and phylogenetic analyses,the viruses possess a stable gene constellation with a Clade 2.3.2.1c HA,a H9N2-derived PB2 gene and the other six genes of Asian H5N1-origin.The Clade 2.3.2.1c H5N1 reassortants displayed a high genetic relationship to a human H5N1 strain(A/Alberta/01/2014).Further analysis showed that similar viruses have been circulating in wild birds in China,Russia,Dubai(Western Asia),Bulgaria and Romania(Europe),as well as domestic poultry in some regions of Africa.The affected areas include the Central Asian,East Asian-Australasian,West Asian-East African,and Black Sea/Mediterranean flyways.These results show that the novel Clade 2.3.2.1c reassortant viruses are circulating worldwide and may have gained a selective advantage in migratory birds,thus posing a serious threat to wild birds and potentially humans.
基金supported by grants from the National Basic Research Program of China (973 Program,2005CB523200)the National High-Tech Research and Development Program of China (863 Program,2006AA10A20 4)+1 种基金the National Key Technology R&D Program (2006BAD 06A04/18/01/03)the National Natural Science Foundation of China (30470072)
文摘Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China＇s pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses （3×103-3×105 TCID50）.The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever （41.0-41.9oC） and high morbidity and mortality （60-100%）,the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection （DPI）.The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.
基金Supported by National Natural Science Foundation of China(30870109)
文摘The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and antibody levels,the epidemic prevention effect of HP-PRRS in Changping District was scientifically assessed.
基金supported by the National Key R&D Program of China(2016YFD0500800)the International Science&Technology Cooperation Program of China(2014DFR31260)
文摘In 2013, a human influenza outbreak caused by a novel H7N9 virus occurred in China. Recently, the H7N9 virus acquired multiple basic amino acids at its hemagglutinin（HA） cleavage site, leading to the emergence of a highly pathogenic virus. The development of an effective diagnostic method is imperative for the prevention and control of highly pathogenic H7N9 influenza. Here, we designed and synthesized three pairs of primers based on the nucleotide sequence at the HA cleavage site of the newly emerged highly pathogenic H7N9 influenza virus. One of the primer pairs and the corresponding probe displayed a high level of amplification efficiency on which a real-time RT-PCR method was established. Amplification using this method resulted in a fluorescent signal for only the highly pathogenic H7N9 virus, and not for any of the H1–H15 subtype reference strains, thus demonstrating high specificity. The method detected as low as 39.1 copies of HA-positive plasmid and exhibited similar sensitivity to the virus isolation method using embryonated chicken eggs. Importantly, the real-time RT-PCR method exhibited 100% consistency with the virus isolation method in the diagnosis of field samples. Collectively, our data demonstrate that this real-time RT-PCR assay is a rapid, sensitive and specific method, and the application will greatly aid the surveillance, prevention, and control of highly pathogenic H7N9 influenza viruses.
基金supported in part by the National Basic Research Program of China(973 Program,2012CB124701)National Natural Science Foundation of China No.81170047,81370151(to DG)+6 种基金Shenzhen overseas high-level talentsinnovation program No.YFZZ20111009(to DG)Shenzhen Nanshan Core Technology Program No.KC2013JSJS0020AShenzhen Municipal Basic Research Program No.JCYJ20130329120507746(to KK)Postdoctoral Science Foundation of China No.2013 M542203(to KK)Hubei Province Research and Development Project No.2011BBB080(to KY)Project supported by the Key Natural Science Foundation of Hubei Province,China No.2012FFA067(to YT)the Opening Subject of Hubei Key Laboratory of Animal Embryo and Molecular Breeding No.2012ZD156(to KY)
文摘Background： Porcine reproductive and respiratory syndrome virus （PRRSV）, and particularly its highly pathogenic genotype （HP-PRRSV）, have caused massive economic losses to the global swine industry. Results： To rapidly identify HP-PRRSV, we developed a direct reaL-time reverse transcription polymerase chain reaction method （dRT-PCR） that could detect the virus from serum specimen without the need of RNA purification Our dRT-PCR assay can be completed in 1.5 h from when a sample is received to obtaining a result. Additionally, the sensitivity of dRT-PCR matched that of conventional reverse transcription PCR （cRT-PCR） that used purified RNA The lowest detection limit of HP-PRRSV was 6.3 TCIDs0 using dRT-PCR. We applied dRT-PCR assay to 144 field samples and the results showed strong consistency with those obtained by cRT-PCR. Moreover, the dRT-PCR method was able to tolerate 5-20% （v/v） serum. Conclusions： Our dRT-PCR assay allows for easier, faster, more cost-effective and higher throughput detection of HP-PRRSV compared with cRT-PCR methods. To the best of our knowledge, this is the first report to describe a real-time RT-PCR assay capable of detecting PRRSV in crude serum samples without the requirement for purifying RNA. We believe our approach has a great potential for application to other RNA viruses.
基金This work was supported by the National Key Research andDevelopment Programof China(2021YFD1800200 and2021YFC2301700).
文摘The stamping-out strategy has been used to control highly pathogenic avian influenza viruses in many countries,driven by the belief that vaccination would not be successful against such viruses and fears that avian influenza virus in vaccinated birds would evolve more rapidly and pose a greater risk to humans.In this review,we summarize the successes in controlling highly pathogenic avian influenza in China and make suggestions regarding the requirements for vaccine selection and effectiveness.In addition,we present evidence that vaccination of poultry not only eliminates human infection with avian influenza virus,but also significantly reduces and abolishes some harmful characteristics of avian influenza virus.
基金This study was supported by the National Major Science and Technology Project for Control and Prevention of Major Infectious Diseases in China[No.2018ZX10711001,2018ZX10305409-004-002]Emergency Prevention and Control Project of Ministry of Science and Technology of China[No.10600100000015001206].
文摘Objective In China, 24 cases of human infection with highly pathogenic avian influenza(HPAI) H5 N6 virus have been confirmed since the first confirmed case in 2014. Therefore, we developed and assessed two H5 N6 candidate vaccine viruses(CVVs).Methods In accordance with the World Health Organization(WHO) recommendations, we constructed two reassortant viruses using reverse genetics(RG) technology to match the two different epidemic H5 N6 viruses. We performed complete genome sequencing to determine the genetic stability. We assessed the growth ability of the studied viruses in MDCK cells and conducted a hemagglutination inhibition assay to analyze their antigenicity. Pathogenicity attenuation was also evaluated in vitro and in vivo.Results The results showed that no mutations occurred in hemagglutinin or neuraminidase, and both CVVs retained their original antigenicity. The replication capacity of the two CVVs reached a level similar to that of A/Puerto Rico/8/34 in MDCK cells. The two CVVs showed low pathogenicity in vitro and in vivo, which are in line with the WHO requirements for CVVs.Conclusion We obtained two genetically stable CVVs of HPAI H5N6 with high growth characteristics,which may aid in our preparedness for a potential H5N6 pandemic.
基金supported by National Natural Science Foundation of China(31672586 and 31830097)the Key Research and Development Program of Guangdong Province(2019B020218004)+2 种基金Earmarked Found for China Agriculture Research System(CARS-41-G16)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2018,Wenbao Qi)Young Scholars of Yangtze River Scholar Professor Program(2019,Wenbao Qi)
文摘Since mid-2016,the low pathogenic H7N9 influenza virus has evolved into a highly pathogenic(HP)phenotype in China,raising many concerns about public health and poultry industry.The insertion of a“KRTA”motif at hemagglutinin cleavage site(HACS)occurred in the early stage of HP H7N9 variants.During the co-circulation,the HACS of HP-H7N9 variants were more polymorphic in birds and humans.Although HP-H7N9 variants,unlike the H5 subtype virus,exhibited the insertions of basic and non-basic amino acids,the underlying function of those insertions and substitutions remains unclear.The results of bioinformatics analysis indicated that the PEVPKRKRTAR/G motif of HACS had become the dominant motif in China.Then,we generated six H7N9 viruses bearing the PEIPKGR/G,PEVPKGR/G,PEVPKRKRTAR/G,PEVPKGKRTAR/G,PEVPKGKRIAR/G,and PEVPKRKRR/G motifs.Interestingly,after the deletion of threonine and alanine(TA)at HACS,the H7N9 viruses manifested decreased thermostability and virulence in mice,and the PEVPKRKRTAR/G-motif virus is prevalent in birds and humans probably due to its increased transmissibility and moderate virulence.By contrast,the insertion of non-basic amino acid isoleucine and alanine(IA)decreased the transmissibility in chickens and virulence in mice.Remarkably,the I335V substitution of H7N9 virus enhanced infectivity and transmission in chickens,suggesting that the combination of mutations and insertions of amino acids at the HACS promoted replication and pathogenicity in chickens and mice.The ongoing evolution of H7N9 increasingly threatens public health and poultry industry,so,its comprehensive surveillance and prevention of H7N9 viruses should be pursued.
基金Supported by Youth Fund Project of Natural Science Foundation of Jiangsu Province(BK20201005)School-Enterprise Cooperation Project of Jiangsu Vocational College of Agriculture and Forestry(2020kj021)。
文摘Porcine reproductive and respiratory syndrome virus(PRRSV) has been mutating and evolving constantly since its emergence in the1980s, which has brought inestimable economic losses to the global swine industry. The virus has two genotypes, of which genotype 1 PRRSV(PRRSV 1) first broke out in Germany and mainly prevailed in Europe, which can be clustered into four subtypes based on the ORF5 sequence. Al-though few cases of PRRSV 1 have been reported in China, the prevention and control of PRRSV should not be ignored. The origin of PRRSV, ge-netic evolution and pathogenicity of PRRSV 1 were retrospectively analyzed, in order to provide valuable evidences for molecular epidemiology and immune prevention and control of PRRSV 1.
文摘At the present stage, the social economy in China has developed by leaps and bounds. China's pig industry has been well developed un-der the background of this era. However, the number of pig diseases increases due to the influence of many factors, and highly pathogenic porcine reproductive and respiratory syndrome(HP-PRRS) is one of the very common diseases, causing growing mortality rate of pigs. The disease increases the economic loss of pig industry to a large extent, and brings difficulties in prevention and control of pig diseases. The staff must analyze and sum-marize the basic characteristics of pig diseases, and combine some practical problems in prevention and control of pig disease to find effective mea-sures. The scope and scale of pig production in different parts of China have been continuously expanded under the background of further develop-ment of pig industry in the new era. But for pig production, pig disease has been a problem that delays its further development. Related personnel must analyze and summarize the status quo of HP-PRRS, to find effective prevention measures and strategy.
文摘The study was designed to evaluate the level of knowledge of Nigerian Veterinary Laboratory Staff on the nature of Highly Pathogenic Avian Influenza (HPAI) disease using structured questionnaires. The study comprised the Staff of National Veterinary Research Institute (NVRI) and five reference Veterinary Teaching Hospitals (VTH) designated for HPAI diagnosis. A total of 69 questionnaires were distributed to the laboratory staff. Questions on the general nature of the disease such as the cause, signs, mode of transmission, methods of identification, lesions, control and prevention, etc. were asked. The results showed that 77.38% of the staff answered all the questions correctly indicating their considerable knowledge of the HPAI disease. Considerable percentage of the staff listed correctly the equipment used for serology (36.23%) and RT-PCR (31.88%). Interestingly only 13.04% of the staff listed correctly the equipment used in rapid tests despite the fact that they are simpler and recommended for all P2 laboratories. In conclusion, the veterinary laboratory staff assessed demonstrated a significant level of knowledge on HPAI diagnosis;however, most of their laboratories lack the structure, organization, funds and basic facilities required for effective HPAI diagnosis.
文摘To evaluate the risk of highly pathogenic avian influenza （HPAI） in China's Mainland, a risk assessment framework was built. Risk factors were determined by analyzing the epidemic data using the brainstorming method; the analytic hierarchy process was designed to weigh risk factors, and the integrated multicriteria analysis was used to evaluate the final result. The completed framework included the risk factor system, data standards for risk factors, weights of risk factors, and integrated assessment methods. This risk assessment framework can be used to quantitatively analyze the outbreak and spread of HPAI in China's Mainland.
基金supported in part by the funding from the National Natural Scientific Foundation(81370518)the National High Technology Research and Development Program of China(2015AA020924 and 2013ZX10004003)supported by a grant from the Beijing Nova Program(No.Z141107001814054)
文摘The highly pathogenic avian influenza （HPAI） H5N1 virus has caused several outbreaks in domestic poultry. Despite great efforts to control the spread of this virus, it continues to evolve and poses a substantial threat to public health because of a high mortality rate. In this study, we sequenced whole genomes of eight H5N1 avian influenza viruses isolated from domestic poultry in eastern China and compared them with those of typical influenza virus strains. Phylogenetic analyses showed that all eight genomes belonged to clade 2.3.2.1 and clade 7.2, the two main circulating clades in China. Viruses that clustered in clade 2.3.2.1 shared a high degree of homology with H5N1 isolates located in eastern Asian. Isolates that clustered in clade 7.2 were found to circulate throughout China, with an east-to-west density gradient. Pathogenicity studies in mice showed that these isolates replicate in the lungs, and clade 2.3.2.1 viruses exhibit a notably higher degree of virulence compared to clade 7.2 viruses. Our results contribute to the elucidation of the biological characterization and pathogenicity of HPAI H5N1 viruses.
