scholarly journals Genetic characterization of influenza A(H3N2) viruses from 2014 to 2017 in Yantai, east of China

2018 ◽  
Vol 42 (3) ◽  
pp. 89-97
Author(s):  
Juan Liu ◽  
Lian-feng Gong ◽  
Zhen-lu Sun ◽  
Qiao Gao ◽  
Zhao-jing Dong
Keyword(s):  
Influenza A ◽  
Eastern China ◽  
Influenza Viruses ◽  
Molecular Surveillance ◽  
Oseltamivir Resistance ◽  
Catalytic Sites ◽  
And Control ◽  
The Given ◽  
Real Challenge

Abstract Background: The genetic variations of influenza viruses pose a real challenge to the vaccine strategies and medical treatment of patients. Methods: In this study, the molecular epidemiology and evolution of influenza A(H3N2) strains were analyzed from April 2014 to March 2017 in Yantai area of eastern China. Results: The phylogenetic analysis of the hemagglutinin (HA) sequences of influenza A(H3N2) showed that all of the influenza A(H3N2) strains during the study period belonged to the genetic clade 3c with the mutations N145S (epitopeA), V186G (epitopeB), P198S (epitopeB) and F219S (epitopeD). Most strains (12/14) of the 2014/2015 season fell into the subgroup 3C.3a characterized by A138S (epitopeA), R142G (epitopeA), F159S (epitopeB) and T128A (epitopeB), while strains isolated from the 2015/2016 and 2016/2017 seasons clustered in 3C.2a shared mutations N144S (epitopeA), F159Y (epitopeB), K160T (epitopeB) and Q311H (epitopeC). The strains isolated from the 2014/2015 and 2015/2016 seasons was were genetically and antigenically distinct from the given vaccine strains. The evaluation of vaccine efficacy (VE) against circulating strains estimated using the pepitope model suggested that little or no protection against circulating strains from 2014/2015 and 2015/2016 seasons was afforded by the given vaccine strains. The sequence analysis of the neuraminidase (NA) showed that all of the analyzed strains had no substitution in the catalytic sites or the framework sites or the supporting the catalytic residues or the oseltamivir resistance substitutions. Conclusions: The results of the study suggested that the vaccine strains provided suboptimal protection against influenza A(H3N2) strains, especially in the 2014/2015 and 2015/2016 seasons and the A(H3N2) strains circulating in the Yantai area were still susceptible to NA inhibitors. Continued systematic antigenic and molecular surveillance of the influenza virus is essential to developing strategies for the prevention and control of influenza.

scholarly journals Continuing evolution of H6N2 influenza a virus in South African chickens and the implications for diagnosis and control

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Celia Abolnik ◽  
Christine Strydom ◽  
Dionne Linda Rauff ◽  
Daniel Barend Rudolph Wandrag ◽  
Deryn Petty
Keyword(s):  
South African ◽  
Influenza A ◽  
Farming Systems ◽  
Influenza Viruses ◽  
True Incidence ◽  
Isolation And Characterization ◽  
Binding Preference ◽  
Continued Use ◽  
And Control

Abstract Background The threat of poultry-origin H6 avian influenza viruses to human health emphasizes the importance of monitoring their evolution. South Africa’s H6N2 epidemic in chickens began in 2001 and two co-circulating antigenic sub-lineages of H6N2 could be distinguished from the outset. The true incidence and prevalence of H6N2 in the country has been difficult to determine, partly due to the continued use of an inactivated whole virus H6N2 vaccine and the inability to distinguish vaccinated from non-vaccinated birds on serology tests. In the present study, the complete genomes of 12 H6N2 viruses isolated from various farming systems between September 2015 and February 2019 in three major chicken-producing regions were analysed and a serological experiment was used to demonstrate the effects of antigenic mismatch in diagnostic tests. Results Genetic drift in H6N2 continued and antigenic diversity in sub-lineage I is increasing; no sub-lineage II viruses were detected. Reassortment patterns indicated epidemiological connections between provinces as well as different farming systems, but there was no reassortment with wild bird or ostrich influenza viruses. The sequence mismatch between the official antigens used for routine hemagglutination inhibition (HI) testing and circulating field strains has increased steadily, and we demonstrated that H6N2 field infections are likely to be missed. More concerning, sub-lineage I H6N2 viruses acquired three of the nine HA mutations associated with human receptor-binding preference (A13S, V187D and A193N) since 2002. Most sub-lineage I viruses isolated since 2015 acquired the K702R mutation in PB2 associated with the ability to infect humans, whereas prior to 2015 most viruses in sub-lineages I and II contained the avian lysine marker. All strains had an unusual HA0 motif of PQVETRGIF or PQVGTRGIF. Conclusions The H6N2 viruses in South African chickens are mutating and reassorting amongst themselves but have remained a genetically pure lineage since they emerged more than 18 years ago. Greater efforts must be made by government and industry in the continuous isolation and characterization of field strains for use as HI antigens, new vaccine seed strains and to monitor the zoonotic threat of H6N2 viruses.

scholarly journals Continuing evolution of H6N2 influenza A virus in South African chickens and the implications for diagnosis and control

2019 ◽  
Author(s):  
Celia Abolnik ◽  
Christine Strydom ◽  
Dionne Linda Rauff ◽  
Daniel Barend Rudolph Wandrag ◽  
Deryn Petty
Keyword(s):  
South African ◽  
Influenza A ◽  
Farming Systems ◽  
Influenza Viruses ◽  
True Incidence ◽  
Isolation And Characterization ◽  
Binding Preference ◽  
Continued Use ◽  
And Control

Abstract Background: The threat of poultry-origin H6 avian influenza viruses to human health emphasizes the importance of monitoring their evolution. South Africa’s H6N2 epidemic in chickens began in 2001 and two co-circulating antigenic sub-lineages of H6N2 could be distinguished from the outset. The true incidence and prevalence of H6N2 in the country has been difficult to determine, partly due to the continued use of an inactivated whole virus H6N2 vaccine and the inability to distinguish vaccinated from non-vaccinated birds on serology tests. In the present study, the complete genomes of twelve H6N2 viruses isolated from various farming systems between September 2015 and February 2019 in three major chicken-producing regions were analysed and a serological experiment was used to demonstrate the effects of antigenic mismatch in diagnostic tests. Results: Genetic drift in H6N2 continued and antigenic diversity in sub-lineage I is increasing; no sub-lineage II viruses were detected. Reassortment patterns indicated epidemiological connections between provinces as well as different farming systems, but there was no reassortment with wild bird or ostrich influenza viruses. The sequence mismatch between the official antigens used for routine hemagglutination inhibition (HI) testing and circulating field strains has increased steadily, and we demonstrated that H6N2 field infections are likely to be missed. More concerning, sub-lineage I H6N2 viruses acquired three of the nine HA mutations associated with human receptor-binding preference (A13S, V187D and A193N) since 2002. Most sub-lineage I viruses isolated since 2015 acquired the K702R mutation in PB2 associated with the ability to infect humans, whereas prior to 2015 most viruses in sub-lineages I and II contained the avian lysine marker. All strains had an unusual HA0 motif of PQVETRGIF or PQVGTRGIF. Conclusions: The H6N2 viruses in South African chickens are mutating and reassorting amongst themselves but have remained a genetically pure lineage since they emerged more than 18 years ago. Greater efforts must be made by government and industry in the continuous isolation and characterization of field strains for use as HI antigens, new vaccine seed strains and to monitor the zoonotic threat of H6N2 viruses.

scholarly journals Continuing evolution of H6N2 influenza A virus in South African chickens and the implications for diagnosis and control

2019 ◽  
Author(s):  
Celia Abolnik ◽  
Christine Strydom ◽  
Dionne Linda Rauff ◽  
Daniel Barend Rudolph Wandrag ◽  
Deryn Petty
Keyword(s):  
South African ◽  
Influenza A ◽  
Farming Systems ◽  
Influenza Viruses ◽  
True Incidence ◽  
Isolation And Characterization ◽  
Binding Preference ◽  
Continued Use ◽  
And Control

Abstract Background: The threat of poultry-origin H6 avian influenza viruses to human health emphasizes the importance of monitoring their evolution. South Africa’s H6N2 epidemic in chickens began in 2001 and two co-circulating antigenic sub-lineages of H6N2 could be distinguished from the outset. The true incidence and prevalence of H6N2 in the country has been difficult to determine, partly due to the continued use of an inactivated whole virus H6N2 vaccine and the inability to distinguish vaccinated from non-vaccinated birds on serology tests. In the present study, the complete genomes of twelve H6N2 viruses isolated from various farming systems between September 2015 and February 2019 in three major chicken-producing regions were analysed and a serological experiment was used to demonstrate the effects of antigenic mismatch in diagnostic tests. Results: Genetic drift in H6N2 continued and antigenic diversity in sub-lineage I is increasing; no sub-lineage II viruses were detected. Reassortment patterns indicated epidemiological connections between provinces as well as different farming systems, but there was no reassortment with wild bird or ostrich influenza viruses. The sequence mismatch between the official antigens used for routine hemagglutination inhibition (HI) testing and circulating field strains has increased steadily, and we demonstrated that H6N2 field infections are likely to be missed. More concerning, sub-lineage I H6N2 viruses acquired three of the nine HA mutations associated with human receptor-binding preference (A13S, V187D and A193N) since 2002. Most sub-lineage I viruses isolated since 2015 acquired the K702R mutation in PB2 associated with the ability to infect humans, whereas prior to 2015 most viruses in sub-lineages I and II contained the avian lysine marker. All strains had an unusual HA 0 motif of PQVETRGIF or PQVGTRGIF. Conclusions: The H6N2 viruses in South African chickens are mutating and reassorting amongst themselves but have remained a genetically pure lineage since they emerged more than 18 years ago. Greater efforts must be made by government and industry in the continuous isolation and characterization of field strains for use as HI antigens, new vaccine seed strains and to monitor the zoonotic threat of H6N2 viruses.

scholarly journals Continuing evolution of H6N2 influenza A virus in South African chickens and the implications for diagnosis and control

2019 ◽  
Author(s):  
Celia Abolnik ◽  
Christine Strydom ◽  
Dionne Linda Rauff ◽  
Daniel Barend Rudolph Wandrag ◽  
Deryn Petty
Keyword(s):  
South African ◽  
Influenza A ◽  
Farming Systems ◽  
Influenza Viruses ◽  
True Incidence ◽  
Isolation And Characterization ◽  
Binding Preference ◽  
Continued Use ◽  
And Control

Abstract Background: The threat of poultry-origin H6 avian influenza viruses to human health emphasizes the importance of monitoring their evolution. South Africa’s H6N2 epidemic in chickens began in 2001 and two co-circulating antigenic sub-lineages of H6N2 could be distinguished from the outset. The true incidence and prevalence of H6N2 in the country has been difficult to determine, partly due to the continued use of an inactivated whole virus H6N2 vaccine and the inability to distinguish vaccinated from non-vaccinated birds on serology tests. In the present study, the complete genomes of twelve H6N2 viruses isolated from various farming systems between September 2015 and February 2019 in three major chicken-producing regions were analysed and a serological experiment was used to demonstrate the effects of antigenic mismatch in diagnostic tests. Results: Genetic drift in H6N2 continued and antigenic diversity in sub-lineage I is increasing; no sub-lineage II viruses were detected. Reassortment patterns indicated epidemiological connections between provinces as well as different farming systems, but there was no reassortment with wild bird or ostrich influenza viruses. The sequence mismatch between the official antigens used for hemagglutination inhibition (HI) testing and circulating field strains has increased steadily, and we demonstrated that these antigens are likely to miss H6N2 field infections. More concerning, sub-lineage I H6N2 viruses have acquired three of the nine HA mutations associated with human receptor-binding preference (A13S, V187D and A193N) since 2002. Most sub-lineage I viruses isolated since 2015 have acquired the K702R mutation in PB2 associated with the ability to infect humans, whereas prior to 2015 most viruses in sub-lineages I and II contained the avian lysine marker. All strains had an unusual HA0 motif of PQVETRGIF or PQVGTRGIF. Conclusions: The H6N2 viruses in South African chickens are mutating and reassorting amongst themselves but have remained a genetically pure lineage since they emerged more than 18 years ago. Greater efforts must be made by government and industry in the continuous isolation and characterization of field strains for use as HI antigens, new vaccine seed strains and to monitor the zoonotic threat of H6N2 viruses.

scholarly journals An evaluation of the InDevR FluChip-8G insight microarray assay in characterizing influenza a viruses

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Emily S. Bailey ◽  
Xinye Wang ◽  
Mai-juan Ma ◽  
Guo-lin Wang ◽  
Gregory C. Gray
Keyword(s):  
Influenza A ◽  
Influenza Viruses ◽  
Time Range ◽  
Influenza B ◽  
Influenza A Viruses ◽  
Laboratory Methods ◽  
Duke University ◽  
Multiple Viral Strains ◽  
Rapid Characterization

AbstractInfluenza viruses are an important cause of disease in both humans and animals, and their detection and characterization can take weeks. In this study, we sought to compare classical virology techniques with a new rapid microarray method for the detection and characterization of a very diverse, panel of animal, environmental, and human clinical or field specimens that were molecularly positive for influenza A alone (n = 111), influenza B alone (n = 3), both viruses (n = 13), or influenza negative (n = 2) viruses. All influenza virus positive samples in this study were first subtyped by traditional laboratory methods, and later evaluated using the FluChip-8G Insight Assay (InDevR Inc. Boulder, CO) in laboratories at Duke University (USA) or at Duke Kunshan University (China). The FluChip-8G Insight multiplexed assay agreed with classical virologic techniques 59 (54.1%) of 109 influenza A-positive, 3 (100%) of the 3 influenza B-positive, 0 (0%) of 10 both influenza A- and B-positive samples, 75% of 24 environmental samples including those positive for H1, H3, H7, H9, N1, and N9 strains, and 80% of 22 avian influenza samples. It had difficulty with avian N6 types and swine H3 and N2 influenza specimens. The FluChip-8G Insight assay performed well with most human, environmental, and animal samples, but had some difficulty with samples containing multiple viral strains and with specific animal influenza strains. As classical virology methods are often iterative and can take weeks, the FluChip-8G Insight Assay rapid results (time range 8 to 12 h) offers considerable time savings. As the FluChip-8G analysis algorithm is expected to improve over time with addition of new subtypes and sample matrices, the FluChip-8G Insight Assay has considerable promise for rapid characterization of novel influenza viruses affecting humans or animals.

Swine influenza vaccines: current status and future perspectives

2010 ◽  
Vol 11 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Wenjun Ma ◽  
Jürgen A. Richt
Keyword(s):  
Influenza A ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Current Status ◽  
Economic Losses ◽  
Influenza A Viruses ◽  
Swine Industry ◽  
Effective Strategies ◽  
Swine Disease ◽  
And Control

AbstractSwine influenza is an important contagious disease in pigs caused by influenza A viruses. Although only three subtypes of influenza A viruses, H1N1, H1N2 and H3N2, predominantly infect pigs worldwide, it is still a big challenge for vaccine manufacturers to produce efficacious vaccines for the prevention and control of swine influenza. Swine influenza viruses not only cause significant economic losses for the swine industry, but are also important zoonotic pathogens. Vaccination is still one of the most important and effective strategies to prevent and control influenza for both the animal and human population. In this review, we will discuss the current status of swine influenza worldwide as well as current and future options to control this economically important swine disease.

scholarly journals Sistema para detección y aislamiento de fallas utilizando Redes de Petri Interpretadas (RPI)

2019 ◽  
pp. 1-5
Author(s):  
Veronica Hernandez ◽  
Alejandro Arredondo ◽  
Elvia Ruiz
Keyword(s):  
Petri Nets ◽  
Discrete Event ◽  
Failure Detection ◽  
Area Of Influence ◽  
And Control ◽  
Failure Monitoring ◽  
The Given ◽  
Implementation In Matlab ◽  
Control Failures

Interpreted Petri Nets (IPN) allow the analysis of Discrete Event Systems (DES) to guarantee the detection of failures in a fast, efficient, and safe way. The objective of this research is the design of an Interpreted Petri Net for the detection of failures in a water supply system. The IPN allows us to identify two types of failures, permanent failures and control failures. The first are inherent to the system and are those that make impossible the functionality of the system. The second refers to those that are inherent to the user and are those failures that do not meet the given specifications. Detecting failures in a system allows the improvement of the operation in such a way that it is more efficient. In this manner, it is possible to design reliable systems which can work properly. In this research, an algorithm was designed for the sensors involved in the system using Interpreted Petri Nets. The detection of failures as main objective is achieved through the implementation of a previously designed IPN. By implementing a programming code in MATLAB®, it was possible to observe its simulated behavior in the system. The input parameters used assume a behavior. Objective: Analyze and implement a mathematical model to automatically detect failures in a system, based on a polynomial algorithm according to the methodology proposed in Matlab®. Methodology: Algorithms were used to characterize the area of influence of the failure in the IPN of the system, from which the implementation in Matlab® showed minimal T-semiflows that do not share any transition with the structure where the failure is located. Therefore, if the problem of linear programming has a solution then the system will be not diagnosable. In this case, if the system is modeled by parts, it is possible to find those parts that are diagnosable and therefore implement the methodology, in this way a module model will be obtained in which the failure detection can be performed. Contribution: Characterization of the diagnosticability property and use of algorithms in MATLAB® to analyze the property of systems designed by IPN. Identify failure occurrence modeled in a system using IPN in MATLAB® for failure monitoring.

scholarly journals EFFECT OF SODIUM MONOFLUOROACETATE ON THE MULTIPLICATION OF INFLUENZA VIRUSES, MUMPS VIRUS, AND PNEUMONIA VIRUS OF MICE (PVM)

1952 ◽  
Vol 96 (6) ◽  
pp. 531-548 ◽  
Author(s):  
William J. Mogabgab ◽  
Frank L. Horsfall
Keyword(s):  
Chick Embryo ◽  
Influenza A ◽  
Virus Titer ◽  
Mumps Virus ◽  
Influenza Viruses ◽  
Mouse Lung ◽  
Influenza B Virus ◽  
Influenza B ◽  
Chick Embryos ◽  
And Control

Sodium fluoroacetate, given after virus inoculation in doses of 3 to 4 mg. per kg. in mice or 2 mg. in chick embryos, caused only a slight delay in the multiplication of the PR8 strain of influenza A virus in the mouse lung and of PR8 or the Lee strain of influenza B virus in the allantoic sac. The quantities of the compound used were sufficient to cause approximately 10 to 20 per cent mortality in mice and 100 per cent in chick embryos. The use of small virus inocula did not markedly increase the effect of sodium fluoroacetate on the multiplication of PR8 or Lee in the chick embryo and maximal titers were obtained in all cases. In contrast to the findings in the chick embryo, sodium fluoroacetate caused a definite delay in the multiplication of Lee virus in the mouse lung but did not affect the final virus titer. Sodium fluoroacetate in like amounts caused only a minimal delay in the multiplication of pneumonia virus of mice (PVM) in the mouse lung or of mumps virus in the chick embryo. With both PVM and mumps virus, maximal titers were obtained almost simultaneously in fluoroacetate and control animals. When three daily injections of the compound were given to mice infected previously with PVM, a definite diminution in the virus titer was demonstrable. However, pretreatment with three daily injections of the compound caused no alteration in the capacity of mice to support the multiplication of PVM. From the results of these experiments, it appears that the cellular metabolic processes blocked by sodium fluoroacetate are not essential for the multiplication of influenza viruses, mumps virus, or pneumonia virus of mice (PVM).

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