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 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 Isolation and Characterization of H4N6 Avian Influenza Viruses from Pigs with Pneumonia in Canada

2000 ◽  
Vol 74 (19) ◽  
pp. 9322-9327 ◽  
Author(s):  
Alexander I. Karasin ◽  
Ian H. Brown ◽  
Suzanne Carman ◽  
Christopher W. Olsen
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Phylogenetic Analyses ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Influenza A Viruses ◽  
Avian Influenza Viruses ◽  
The North ◽  
Isolation And Characterization

ABSTRACT In October 1999, H4N6 influenza A viruses were isolated from pigs with pneumonia on a commercial swine farm in Canada. Phylogenetic analyses of the sequences of all eight viral RNA segments demonstrated that these are wholly avian influenza viruses of the North American lineage. To our knowledge, this is the first report of interspecies transmission of an avian H4 influenza virus to domestic pigs under natural conditions.

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.

scholarly journals Isolation and Characterization of Bacteriophage ZCSE6 against Salmonella spp.: Phage Application in Milk

Biologics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 164-176
Author(s):  
Abdallah S. Abdelsattar ◽  
Anan Safwat ◽  
Rana Nofal ◽  
Amera Elsayed ◽  
Salsabil Makky ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Raw Milk ◽  
Salmonella Spp ◽  
Isolation And Characterization ◽  
Food Borne ◽  
Wide Range ◽  
Almost All ◽  
And Control ◽  
Milk And Dairy Products

Food safety is very important in the food industry as most pathogenic bacteria can cause food-borne diseases and negatively affect public health. In the milk industry, contamination with Salmonella has always been a challenge, but the risks have dramatically increased as almost all bacteria now show resistance to a wide range of commercial antibiotics. This study aimed to isolate a bacteriophage to be used as a bactericidal agent against Salmonella in milk and dairy products. Here, phage ZCSE6 has been isolated from raw milk sample sand molecularly and chemically characterized. At different multiplicities of infection (MOIs) of 0.1, 0.01, and 0.001, the phage–Salmonella interaction was studied for 6 h at 37 °C and 24 h at 8 °C. In addition, ZCSE6 was tested against Salmonella contamination in milk to examine its lytic activity for 3 h at 37 °C. The results showed that ZCSE6 has a small genome size (<48.5 kbp) and belongs to the Siphovirus family. Phage ZCSE6 revealed a high thermal and pH stability at various conditions that mimic milk manufacturing and supply chain conditions. It also demonstrated a significant reduction in Salmonella concentration in media at various MOIs, with higher bacterial eradication at higher MOI. Moreover, it significantly reduced Salmonella growth (MOI 1) in milk, manifesting a 1000-fold decrease in bacteria concentration following 3 h incubation at 37 °C. The results highlighted the strong ability of ZCSE6 to kill Salmonella and control its growth in milk. Thus, ZCSE6 is recommended as a biocontrol agent in milk to limit bacterial growth and increase the milk shelf-life.

scholarly journals Isolation and characterization of low pathogenic H9N2 avian influenza A viruses from a healthy flock and its comparison to other H9N2 isolates

2013 ◽  
Vol 24 (3) ◽  
pp. 342-348 ◽  
Author(s):  
Muhammad Munir ◽  
Siamak Zohari ◽  
Muhammad Abbas ◽  
Muhammad Zubair Shabbir ◽  
Muhammad Nauman Zahid ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza A Viruses ◽  
Isolation And Characterization

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.

Sign in / Sign up

Export Citation Format

Share Document