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Kaveh K, Tazarghi A, Hosseini P, Fotouhi F, Ajorloo M, Rabiei Roodsari M, Razavi Nikoo H. Molecular characterization of the neuraminidase gene of influenza B virus in Northern Iran. Virusdisease 2023; 34:21-28. [PMID: 37009253 PMCID: PMC10050514 DOI: 10.1007/s13337-022-00806-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/28/2022] [Indexed: 02/19/2023] Open
Abstract
Neuraminidase inhibitors are the only FDA-approved class of antiviral agents against influenza B viruses. Resistance to these drugs has been reported from different parts of the world; however, there seems to be not enough information about this issue in Iran. We aimed to study the genetic evolution of these viruses as well as the presence of possible mutations concerning drug resistance in northern Iran. RNA was extracted from naso- and oropharyngeal swabs and amplified by one-step RT-PCR for detection and sequencing of the neuraminidase gene. All the data were edited and assembled utilizing BioEdit DNASequence Alignment Editor Software, and the phylogenetic tree was constructed via MEGA software version 10. Finally, resistance-associated mutations and B-cell epitopes substitutions were assessed by comparing our sequences with the counterparts in the reference strains. Comparing our sequences with reference strains revealed that the analyzed isolates of influenza B pertained to the B-Yamagata lineage, had a few B-cell epitopes alterations, and contained no particular mutations concerning resistance against neuraminidase inhibitors, such as oseltamivir. Our findings suggest that all the strains circulating in northern Iran and hopefully other parts of the country can be considered sensitive to this class of drugs. Although it is promising, we strongly recommend additional investigations to evaluate the impact of such drug-resistant mutations in other regions, which in turn will assist the public health agencies in taking immediate and effective therapeutic measures into account when needed.
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Affiliation(s)
- Kimia Kaveh
- Department of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Abbas Tazarghi
- Department of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Parastoo Hosseini
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Fotouhi
- Influenza Research Lab, Department of Virology, Pasteur Institute of Iran, Tehran, Iran
| | - Mehdi Ajorloo
- Blood Transfusion Research Center, High Institute of Research and Education in Transfusion Medicine, Tehran, Iran
| | - Mehdi Rabiei Roodsari
- Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Hadi Razavi Nikoo
- Department of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
- Infectious Disease Research Center, Golestan University of Medical Sciences, Gorgan, Iran
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Yoshihara K, Minh LN, Okada T, Toizumi M, Nguyen HA, Vo HM, Hashizume M, Dang DA, Kimura H, Yoshida LM. Evolutionary dynamics of influenza B strains detected from paediatric acute respiratory infections in central Vietnam. INFECTION GENETICS AND EVOLUTION 2020; 81:104264. [PMID: 32105864 DOI: 10.1016/j.meegid.2020.104264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/07/2020] [Accepted: 02/22/2020] [Indexed: 11/28/2022]
Abstract
Influenza virus B belongs to the family Orthomyxoviridae with segmented negative-sense RNA genomes. Since 1970s, influenza B has diverged intoVictoria and Yamagata, which differs in antigenic and evolutionary characteristics. Yet, molecular-epidemiological information of influenza B from developing nations is limited. In central Vietnam, influenza A subtype-specific circulation pattern and clinical characteristics were previously described. However, molecular evolutionary characteristics of influenza B has not been discussed to date. We utilized the influenza B positives obtained from paediatric ARI surveillance during 2007-2013. Influenza B HA and NA genes were amplified, sequenced, and phylogenetic/molecular evolutionary analysis was performed using Maximum Likelihood and Bayesian MCMC. Phylodynamics analysis was performed with Bayesian Skyline Plot (BSP). Furthermore, we performed selection pressure analysis and estimated N-glycosylation sites. In the current study, overall positive rate for influenza B was 3.0%, and Victoria lineage immediately became predominant in post-A/H1N1pdm09 period. The noticeable shift in Victoria lineage WHO Group occurred. With respect to the evolutionary rate (substitutions/site/year), Victoria lineage HA gene was evolving faster than Yamagata lineage (2.43 × 10-3 vs 2.00 × 10-3). Furthermore, the evolutionary rate of Victoria Group 5 was greater than Group 1. BSP presented the rapid growth in Effective Population Size (EPS) of Victoria lineage occurred soon after the 1st A/H1N1pdm09 case was detected whereas the EPS of Yamagata lineage was stable for both genes. N-glycosylation pattern between lineages and among WHO Groups were slightly different, and HA gene had a total of 6 amino acid substitutions under positive section pressure (4 for Victoria and 2 for Yamagata). The current results highlight the importance of Victoria lineage in post-A/H1N1pdm09 period. Difference in evolutionary characteristics and phylodynamics may indicate lineage and WHO Group-specific evolutionary dynamics. It is necessary to further continue the molecular-epidemiological surveillance in local setting to gain a better understanding of local evolutionary characteristics of influenza B strains.
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Affiliation(s)
- Keisuke Yoshihara
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan
| | - Le Nhat Minh
- National Institute of Hygiene and Epidemiology, Hanoi 100000, Viet Nam
| | - Takashi Okada
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan
| | - Michiko Toizumi
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan
| | - Hien Anh Nguyen
- National Institute of Hygiene and Epidemiology, Hanoi 100000, Viet Nam
| | - Hien Minh Vo
- Department of Paediatrics, Khanh Hoa General Hospital, Nha Trang 650000, Viet Nam
| | - Masahiro Hashizume
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan
| | - Duc Anh Dang
- National Institute of Hygiene and Epidemiology, Hanoi 100000, Viet Nam
| | - Hirokazu Kimura
- School of Medical Technology, Gunma Paz University, Takasaki-shi, Gunma, 370-0006, Japan
| | - Lay-Myint Yoshida
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan.
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Spatial, Temporal and Genetic Dynamics Characteristics of Influenza B Viruses in China, 1973-2018. Virol Sin 2019; 35:14-20. [PMID: 31637629 DOI: 10.1007/s12250-019-00161-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 08/08/2019] [Indexed: 12/14/2022] Open
Abstract
Annual influenza B virus epidemics and outbreaks cause severe influenza diseases in humans and pose a threat to public health. China is an important epidemic area of influenza B viruses. However, the spatial, temporal transmission pathways and the demography history of influenza B viruses in China remain unknown. We collected the haemagglutinin gene sequences sampled of influenza B virus in China between 1973 and 2018. A Bayesian Markov chain Monte Carlo phylogeographic discrete approach was used to infer the spatial and temporal phylodynamics of influenza B virus. The Bayesian phylogeographic analysis of influenza B viruses showed that the North subtropical and South subtropical zones are the origins of the Victoria and Yamagata lineage viruses, respectively. Furthermore, the South temperate and North subtropical zones acted as transition nodes in the Victoria lineage virus dispersion network and that the North subtropical and Mid subtropical zones acted as transition nodes in the Yamagata lineage virus dispersion network. Our findings contribute to the knowledge regarding the spatial and temporal patterns of influenza B virus outbreaks in China.
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Yoshihara K, Le MN, Toizumi M, Nguyen HA, Vo HM, Odagiri T, Fujisaki S, Ariyoshi K, Moriuchi H, Hashizume M, Dang DA, Yoshida LM. Influenza B associated paediatric acute respiratory infection hospitalization in central vietnam. Influenza Other Respir Viruses 2019; 13:248-261. [PMID: 30575288 PMCID: PMC6468073 DOI: 10.1111/irv.12626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 12/06/2018] [Accepted: 12/08/2018] [Indexed: 11/28/2022] Open
Abstract
Background Influenza B is one of the major etiologies for acute respiratory infections (ARI) among children worldwide; however, its clinical‐epidemiological information is limited. We aimed to investigate the hospitalization incidence and clinical‐epidemiological characteristics of influenza B‐associated paediatric ARIs in central Vietnam. Methods We collected clinical‐epidemiological information and nasopharyngeal swabs from ARI children hospitalized at Khanh Hoa General Hospital, Nha Trang, Vietnam from February 2007 through June 2013. Nasopharyngeal samples were screened for 13 respiratory viruses using Multiplex‐PCRs. Influenza B‐confirmed cases were genotyped by Haemagglutinin gene sequencing. We analyzed the clinical‐epidemiological characteristics of influenza B Lineages (Victoria/Yamagata) and WHO Groups. Results In the pre‐A/H1N1pdm09 period, influenza B‐associated ARI hospitalization incidence among children under five was low, ranging between 14.7 and 80.7 per 100 000 population. The incidence increased to between 51.4 and 330 in the post‐A/H1N1pdm09. Influenza B ARI cases were slightly older with milder symptoms. Both Victoria and Yamagata lineages were detected before the A/H1N1pdm09 outbreak; however, Victoria lineage became predominant in 2010‐2013 (84% Victoria vs 16% Yamagata). Victoria and Yamagata lineages did not differ in demographic and clinical characteristics. In Victoria lineage, Group1 ARI cases were clinically more severe compared to Group5, presenting a greater proportion of wheeze, tachypnea, and lower respiratory tract infection. Conclusions The current results highlight the increased incidence of influenza B‐related ARI hospitalization among children in central Vietnam in the post‐A/H1N1pdm09 era. Furthermore, the difference in clinical severity between Victoria lineage Group1 and 5 implies the importance of influenza B genetic variation on clinical presentation.
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Affiliation(s)
- Keisuke Yoshihara
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Minh Nhat Le
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.,National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Michiko Toizumi
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Hien Anh Nguyen
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | | | - Takato Odagiri
- Influenza Virus Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Seiichiro Fujisaki
- Influenza Virus Research Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Koya Ariyoshi
- Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.,Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Hiroyuki Moriuchi
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.,Department of Paediatrics, Nagasaki University Hospital, Nagasaki, Japan
| | - Masahiro Hashizume
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.,Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Duc Anh Dang
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Lay-Myint Yoshida
- Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.,Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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5
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Koul PA, Potdar V, Showkat M, Mir H, Chadha MS. Influenza B in a temperate region of northern India 2010-2016: co-circulation of the two lineages with northern hemispherical seasonality. Virusdisease 2018; 29:553-559. [PMID: 30539062 DOI: 10.1007/s13337-018-0487-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/10/2018] [Indexed: 11/29/2022] Open
Abstract
Scant data exist about the epidemiology of influenza B in India. We set out to address the epidemiology of influenza B in a temperate region of northern India from 2010 to 2016. Outpatient and inpatient surveillance was conducted in patients presenting with acute respiratory infection in a northern Indian hospital from September 2010 till April 2016. After recording clinical data, combined nasal/throat swabs were collected and tested for influenza viruses by real time RT-PCR. Influenza A viruses were further subtyped into A/H3N2 and A/H1N1 whereas influenza B were differentiated into B/Yamagata and B/Victoria. Virus isolation, haemaggglutination inhibition testing, sequencing and phylogenetic analysis was carried out on representative samples. Of the 6879 recruited cases, influenza B was detected in 299 (4.3%). The patients presented with respiratory symptoms of varying duration; cough, fever and nasal discharge being the most common. The peaking of the activity of the circulation showed a correlation with the onset of the winter with reduced temperatures and high dry humidity. B/Victoria lineage was detected in 35.4% (n = 106/299) whereas 53.8% (n = 161/299) were B/Yamagata. The circulation in each season was dominated by one lineage which correlated with the vaccine strain, but up to 37% consisted of a different lineage. We conclude that Influenza B exhibits a northern hemispherical seasonality in temperate northern India with co-circulation of the 2 lineages of influenza B. These findings have relevance for vaccine effectiveness and argue for vaccination with a quadrivalent influenza vaccine.
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Affiliation(s)
- Parvaiz A Koul
- 1Influenza Laboratory, Department of Internal and Pulmonary Medicine, Sheri Kashmir Institute of Medical Sciences, Srinagar, J&K 190011 India
| | - Varsha Potdar
- 2National Institute of Virology, Pune, Mahrashtra India
| | - Masooma Showkat
- 1Influenza Laboratory, Department of Internal and Pulmonary Medicine, Sheri Kashmir Institute of Medical Sciences, Srinagar, J&K 190011 India
| | - Hyder Mir
- 1Influenza Laboratory, Department of Internal and Pulmonary Medicine, Sheri Kashmir Institute of Medical Sciences, Srinagar, J&K 190011 India
| | - M S Chadha
- 2National Institute of Virology, Pune, Mahrashtra India
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Orsi A, Colomba GME, Pojero F, Calamusa G, Alicino C, Trucchi C, Canepa P, Ansaldi F, Vitale F, Tramuto F. Trends of influenza B during the 2010-2016 seasons in 2 regions of north and south Italy: The impact of the vaccine mismatch on influenza immunisation strategy. Hum Vaccin Immunother 2018; 14:523-531. [PMID: 28708953 PMCID: PMC5861802 DOI: 10.1080/21645515.2017.1342907] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/22/2017] [Accepted: 06/12/2017] [Indexed: 10/19/2022] Open
Abstract
Influenza A and B viruses are responsible for respiratory infections, representing globally seasonal threats to human health. The 2 viral types often co-circulate and influenza B plays an important role in the spread of infection. A 6-year retrospective surveillance study was conducted between 2010 and 2016 in 2 large administrative regions of Italy, located in the north (Liguria) and in the south (Sicily) of the country, to describe the burden and epidemiology of both B/Victoria and B/Yamagata lineages in different healthcare settings. Influenza B viruses were detected in 5 of 6 seasonal outbreaks, exceeding influenza A during the season 2012-2013. Most of influenza B infections were found in children aged ≤ 14 y and significant differences were observed in the age-groups infected by the different lineages. B/Victoria strains prevailed in younger population than B/Yamagata, but also were more frequently found in the community setting. Conversely, B/Yamagata viruses were prevalent among hospitalized cases suggesting their potential role in the development of more severe disease. The relative proportions of viral lineages varied from year to year, resulting in different lineage-level mismatch for the B component of trivalent influenza vaccine. Our findings confirmed the need for continuous virological surveillance of seasonal epidemics and bring attention to the adoption of universal influenza immunization program in the childhood. The use of tetravalent vaccine formulations may be useful to improve the prevention and control of the influenza burden in general population.
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Affiliation(s)
- Andrea Orsi
- Department of Health Sciences, University of Genoa, Genoa, Italy
- Hygiene Unit, IRCCS University Hospital “San Martino” - IST National Institute for Cancer Research, Genoa, Italy
| | - Giuseppina Maria Elena Colomba
- Department of Health Promotion Sciences and Mother-Child Care “G. D'Alessandro” – Hygiene section, University of Palermo, Palermo, Italy
| | - Fanny Pojero
- Department of Health Promotion Sciences and Mother-Child Care “G. D'Alessandro” – Hygiene section, University of Palermo, Palermo, Italy
| | - Giuseppe Calamusa
- Department of Health Promotion Sciences and Mother-Child Care “G. D'Alessandro” – Hygiene section, University of Palermo, Palermo, Italy
| | | | - Cecilia Trucchi
- Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Paola Canepa
- Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Filippo Ansaldi
- Department of Health Sciences, University of Genoa, Genoa, Italy
- Hygiene Unit, IRCCS University Hospital “San Martino” - IST National Institute for Cancer Research, Genoa, Italy
| | - Francesco Vitale
- Department of Health Promotion Sciences and Mother-Child Care “G. D'Alessandro” – Hygiene section, University of Palermo, Palermo, Italy
- Clinical Epidemiology Unit, University Hospital “Paolo Giaccone”, Palermo, Italy
| | - Fabio Tramuto
- Department of Health Promotion Sciences and Mother-Child Care “G. D'Alessandro” – Hygiene section, University of Palermo, Palermo, Italy
- Clinical Epidemiology Unit, University Hospital “Paolo Giaccone”, Palermo, Italy
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7
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Arencibia A, Piñón A, Acosta B, Fernandez L, Muné M, Valdés O, Savón C, Oropesa S, Gonzalez G, Roque R, Gonzalez G, Hernández B, Alfonso JM. Vaccine-mismatched influenza B/Yamagata lineage viruses in Cuba, 2012-2013 season. INFECTION GENETICS AND EVOLUTION 2017; 58:110-114. [PMID: 29229320 DOI: 10.1016/j.meegid.2017.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 11/24/2017] [Accepted: 12/06/2017] [Indexed: 10/18/2022]
Abstract
Annual trivalent influenza vaccines contain one of influenza B lineages; influenza B/Victoria-lineage or influenza B/Yamagata viruses. Theoretically, these vaccines should protect against viruses expected to circulate in the next influenza season. The National Influenza Centers, based on surveillance data from National Reference Laboratories, selects the strains composing each annual trivalent or tetravalent vaccine. Nevertheless, in some epidemics, vaccine strains do not match genetically with circulating strains. The aim of the present study is to compare the HA1-domain of 42 influenza B viruses circulating in Cuba during the 2012-2013 season with the vaccine strain B/Wisconsin/01/2010-like virus from the B/Yamagata lineage, included in the 2012-2013 Northern-Hemisphere Influenza vaccine. The efficacy of the influenza vaccine was also estimated. The analysis of the present study indicates that the B/Victoria and B/Yamagata lineages co-circulated in Cuba in the 2012-2013 season. In 2012-2013 season, according to the sequences analysis, trivalent vaccine did not match with the circulating strains. The present study also detected amino acid substitutions which could have altered the antigenic properties of HA gene. The results presented here suggest the need to consider a possible introduction of tetravalent influenza vaccine in Cuba, as has been recommended by the WHO to ensure higher levels of protection.
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Affiliation(s)
| | - Alexander Piñón
- University of Miami, Miller School of Medicine, Department of Surgery Transplant, 1600 NW 10th Ave., Miami, FL 33136, United States
| | | | | | - Mayra Muné
- Pedro Kourí Tropical Medicine Institute, Cuba
| | | | - Clara Savón
- Pedro Kourí Tropical Medicine Institute, Cuba
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Langat P, Raghwani J, Dudas G, Bowden TA, Edwards S, Gall A, Bedford T, Rambaut A, Daniels RS, Russell CA, Pybus OG, McCauley J, Kellam P, Watson SJ. Genome-wide evolutionary dynamics of influenza B viruses on a global scale. PLoS Pathog 2017; 13:e1006749. [PMID: 29284042 PMCID: PMC5790164 DOI: 10.1371/journal.ppat.1006749] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/10/2018] [Accepted: 11/13/2017] [Indexed: 12/14/2022] Open
Abstract
The global-scale epidemiology and genome-wide evolutionary dynamics of influenza B remain poorly understood compared with influenza A viruses. We compiled a spatio-temporally comprehensive dataset of influenza B viruses, comprising over 2,500 genomes sampled worldwide between 1987 and 2015, including 382 newly-sequenced genomes that fill substantial gaps in previous molecular surveillance studies. Our contributed data increase the number of available influenza B virus genomes in Europe, Africa and Central Asia, improving the global context to study influenza B viruses. We reveal Yamagata-lineage diversity results from co-circulation of two antigenically-distinct groups that also segregate genetically across the entire genome, without evidence of intra-lineage reassortment. In contrast, Victoria-lineage diversity stems from geographic segregation of different genetic clades, with variability in the degree of geographic spread among clades. Differences between the lineages are reflected in their antigenic dynamics, as Yamagata-lineage viruses show alternating dominance between antigenic groups, while Victoria-lineage viruses show antigenic drift of a single lineage. Structural mapping of amino acid substitutions on trunk branches of influenza B gene phylogenies further supports these antigenic differences and highlights two potential mechanisms of adaptation for polymerase activity. Our study provides new insights into the epidemiological and molecular processes shaping influenza B virus evolution globally.
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Affiliation(s)
- Pinky Langat
- Wellcome Trust Sanger Institute, Hinxton, United
Kingdom
| | - Jayna Raghwani
- Department of Zoology, University of Oxford, Oxford, United
Kingdom
| | - Gytis Dudas
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh,
United Kingdom
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research
Center, Seattle, Washington, United States of America
| | - Thomas A. Bowden
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics,
University of Oxford, Oxford, United Kingdom
| | | | - Astrid Gall
- Wellcome Trust Sanger Institute, Hinxton, United
Kingdom
| | - Trevor Bedford
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research
Center, Seattle, Washington, United States of America
| | - Andrew Rambaut
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh,
United Kingdom
- Fogarty International Center, National Institutes of Health, Bethesda,
Maryland, United States of America
| | - Rodney S. Daniels
- Worldwide Influenza Centre, The Francis Crick Institute, London, United
Kingdom
| | - Colin A. Russell
- Department of Veterinary Medicine, University of Cambridge, Cambridge,
United Kingdom
| | - Oliver G. Pybus
- Department of Zoology, University of Oxford, Oxford, United
Kingdom
| | - John McCauley
- Worldwide Influenza Centre, The Francis Crick Institute, London, United
Kingdom
| | - Paul Kellam
- Wellcome Trust Sanger Institute, Hinxton, United
Kingdom
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9
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Han SB, Rhim JW, Shin HJ, Lee SY, Kim HH, Kim JH, Lee KY, Ma SH, Park JS, Kim HM, Kim CS, Kim DH, Choi YY, Cha SH, Hong YJ, Kang JH. Immunogenicity and safety assessment of a trivalent, inactivated split influenza vaccine in Korean children: Double-blind, randomized, active-controlled multicenter phase III clinical trial. Hum Vaccin Immunother 2016; 11:1094-102. [PMID: 25875868 PMCID: PMC4514431 DOI: 10.1080/21645515.2015.1017693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A multicenter, double-blind, randomized, active-control phase III clinical trial was performed to assess the immunogenicity and safety of a trivalent, inactivated split influenza vaccine. Korean children between the ages of 6 months and 18 y were enrolled and randomized into a study (study vaccine) or a control vaccine group (commercially available trivalent, inactivated split influenza vaccine) in a 5:1 ratio. Antibody responses were determined using hemagglutination inhibition assay, and post-vaccination immunogenicity was assessed based on seroconversion and seroprotection rates. For safety assessment, solicited local and systemic adverse events up to 28 d after vaccination and unsolicited adverse events up to 6 months after vaccination were evaluated. Immunogenicity was assessed in 337 and 68 children of the study and control groups. In the study vaccine group, seroconversion rates against influenza A/H1N1, A/H3N2, and B strains were 62.0% (95% CI: 56.8–67.2), 53.4% (95% CI: 48.1–58.7), and 54.9% (95% CI: 48.1–60.2), respectively. The corresponding seroprotection rates were 95.0% (95% CI: 92.6–97.3), 93.8% (95% CI: 91.2–96.4), and 95.3% (95% CI: 93.0–97.5). The lower 95% CI limits of the seroconversion and seroprotection rates were over 40% and 70%, respectively, against all strains. Seroconversion and seroprotection rates were not significantly different between the study and control vaccine groups. Furthermore, the frequencies of adverse events were not significantly different between the 2 vaccine groups, and no serious vaccination-related adverse events were noted. In conclusion, the study vaccine exhibited substantial immunogenicity and safety in Korean children and is expected to be clinically effective.
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Affiliation(s)
- Seung Beom Han
- a Department of Pediatrics; The Catholic University of Korea College of Medicine ; Seoul , Republic of Korea
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10
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Oong XY, Ng KT, Lam TTY, Pang YK, Chan KG, Hanafi NS, Kamarulzaman A, Tee KK. Epidemiological and Evolutionary Dynamics of Influenza B Viruses in Malaysia, 2012-2014. PLoS One 2015; 10:e0136254. [PMID: 26313754 PMCID: PMC4552379 DOI: 10.1371/journal.pone.0136254] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/01/2015] [Indexed: 12/16/2022] Open
Abstract
Epidemiological and evolutionary dynamics of influenza B Victoria and Yamagata lineages remained poorly understood in the tropical Southeast Asia region, despite causing seasonal outbreaks worldwide. From 2012-2014, nasopharyngeal swab samples collected from outpatients experiencing acute upper respiratory tract infection symptoms in Kuala Lumpur, Malaysia, were screened for influenza viruses using a multiplex RT-PCR assay. Among 2,010/3,935 (51.1%) patients infected with at least one respiratory virus, 287 (14.3%) and 183 (9.1%) samples were tested positive for influenza A and B viruses, respectively. Influenza-positive cases correlate significantly with meteorological factors-total amount of rainfall, relative humidity, number of rain days, ground temperature and particulate matter (PM10). Phylogenetic reconstruction of haemagglutinin (HA) gene from 168 influenza B viruses grouped them into Yamagata Clade 3 (65, 38.7%), Yamagata Clade 2 (48, 28.6%) and Victoria Clade 1 (55, 32.7%). With neuraminidase (NA) phylogeny, 30 intra-clade (29 within Yamagata Clade 3, 1 within Victoria Clade 1) and 1 inter-clade (Yamagata Clade 2-HA/Yamagata Clade 3-NA) reassortants were identified. Study of virus temporal dynamics revealed a lineage shift from Victoria to Yamagata (2012-2013), and a clade shift from Yamagata Clade 2 to Clade 3 (2013-2014). Yamagata Clade 3 predominating in 2014 consisted of intra-clade reassortants that were closely related to a recent WHO vaccine candidate strain (B/Phuket/3073/2013), with the reassortment event occurred approximately 2 years ago based on Bayesian molecular clock estimation. Malaysian Victoria Clade 1 viruses carried H274Y substitution in the active site of neuraminidase, which confers resistance to oseltamivir. Statistical analyses on clinical and demographic data showed Yamagata-infected patients were older and more likely to experience headache while Victoria-infected patients were more likely to experience nasal congestion and sore throat. This study describes the evolution of influenza B viruses in Malaysia and highlights the importance of continuous surveillance for better vaccination policy in this region.
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Affiliation(s)
- Xiang Yong Oong
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kim Tien Ng
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tommy Tsan-Yuk Lam
- School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China
| | - Yong Kek Pang
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Nik Sherina Hanafi
- Department of Primary Care Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Adeeba Kamarulzaman
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok Keng Tee
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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11
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Fang Q, Gao Y, Chen M, Guo X, Yang X, Wei L. Molecular epidemiology and evolution of influenza A and B viruses during winter 2013-2014 in Beijing, China. Arch Virol 2015; 160:1083-95. [PMID: 25676826 DOI: 10.1007/s00705-015-2362-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/31/2015] [Indexed: 11/25/2022]
Abstract
In this study, we investigated the molecular epidemiology and evolution of influenza viruses from patients infected during the 2013-2014 influenza season in Beijing. A phylogenetic analysis of the hemagglutinin (HA) and neuraminidase (NA) sequences of influenza A and B viruses from 18 patients (6 A(H1N1)pdm09, 4 H3N2, and 8 influenza B virus) was performed. Among the influenza A viruses, A(H1N1)pdm09 was the dominant subtype, whereas the B/Yamagata lineage was predominant for influenza B. The influenza B HA and NA strains in Beijing were dominated by reassortants derived from the Yamagata lineage and the Victoria lineage, respectively. All six A(H1N1)pdm09 strains fell into the 6B genetic group with amino acid substitutions D97N, S185T, K163Q, and A256T; the four H3N2 strains fell into genetic group 3C.3 with substitutions T128A, R142G, N145S, and V186G, and the eight influenza B strains were categorized into subgroup 3.1 and harbored an N217S mutation. Two new mutations (K180Q and G187E at the Sa and Ca antigenic sites of the H1 segment, respectively), which were not detected during the preceding influenza season, were identified. Mutations N131K, S165I, N181Y, and D212N in HA of influenza B mapped to the 120-loop, 150-loop, 160-loop, and 190-helix, respectively. Our results reveal the molecular epidemiology and phylogenetic characteristics of influenza viruses within a single geographic location and can have implications for vaccination selection in northern China.
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Affiliation(s)
- Qiongxuan Fang
- Department of Infectious Disease, Peking University Hepatology Institute, Peking University People's Hospital, Xizhimen South Street, Xicheng District, No. 11, Beijing, 100044, China
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12
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Christopoulou I, Roose K, Ibañez LI, Saelens X. Influenza vaccines to control influenza-associated bacterial infection: where do we stand? Expert Rev Vaccines 2014; 14:55-67. [DOI: 10.1586/14760584.2015.957191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Roy Mukherjee T, Chanda S, Mullick S, De P, Dey‐Sarkar M, Chawla‐Sarkar M. Spectrum of respiratory viruses circulating in eastern India: prospective surveillance among patients with influenza-like illness during 2010-2011. J Med Virol 2013; 85:1459-65. [PMID: 23765782 PMCID: PMC7166942 DOI: 10.1002/jmv.23607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2013] [Indexed: 11/07/2022]
Abstract
In developing countries, viruses causing respiratory disease are a major concern of public health. During January 2010-December 2011, 2,737 patients with acute respiratory infection from the outpatient departments as well as patients admitted to hospitals were screened for different respiratory viruses. Nasal and or throat swabs were collected and transported to the laboratory where initial screening of influenza A and influenza B viruses was performed. The samples were tested further for influenza C virus, parainfluenza viruses 1-4, human rhinovirus, metapneumovirus and respiratory syncytial virus by conventional RT- PCR. The study revealed that the majority of the patients were under 5 years of age; both due to their higher susceptibility to respiratory infections and presentation to hospitals. Out of 2,737 patients enrolled in this study, 59% were found positive for one or more respiratory viruses. Influenza B infection was detected in 12% of patients followed by influenza A (11.7%), respiratory syncytial virus (7.1%), parainfluenza virus-2 (6%), metapneumovirus (3%), parainfluenza virus-3 (1%), parainfluenza virus-4 (0.6%), parainfluenza virus-1 (0.3%), influenza C (0.2%) and human rhinovirus (0.2%). Distinct seasonal infection was observed only for influenza A and influenza B viruses.
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Affiliation(s)
| | - Shampa Chanda
- National Institute of Cholera and Enteric DiseasesBeliaghata, KolkataIndia
| | - Satarupa Mullick
- National Institute of Cholera and Enteric DiseasesBeliaghata, KolkataIndia
| | - Papiya De
- National Institute of Cholera and Enteric DiseasesBeliaghata, KolkataIndia
| | - Malay Dey‐Sarkar
- National Institute of Cholera and Enteric DiseasesBeliaghata, KolkataIndia
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14
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Ali G, Amer HM, Almajhdi FN. Hemagglutinin and neuraminidase genes of influenza B viruses circulating in Riyadh, Saudi Arabia during 2010-2011: evolution and sequence analysis. J Med Virol 2013; 86:1003-16. [PMID: 24150926 DOI: 10.1002/jmv.23819] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2013] [Indexed: 12/12/2022]
Abstract
Influenza viruses are known as continuing threats to human public health every year worldwide. Evolutionary dynamics of influenza B viruses in humans are in a unique progression having two lineages; B/Yam and B/Vic-like viruses, which are circulating simultaneously worldwide. There is a considerable lack of data on influenza B viruses circulating in Saudi Arabia. During the winter-spring season of 2010-2011, 80 nasopharyngeal aspirates were collected from hospitalized patients with flu-like symptoms in Riyadh. Screening of samples by one-step RT-PCR identified three (3.8%) influenza B viruses. Sequencing of hemagglutinin (HA) and neuraminidase (NA) genes was performed to analyze influenza B viruses circulating in Riyadh as compared to the globally circulating strains. Several common and six unique amino acid substitutions were observed for both HA and NA genes of influenza B Saudi strains. Three unique substitutions (T182A, D196N, and K254R) were identified in HA gene of the B/Yam-like Riyadh strains. In NA gene, a unique common substitution (D53G) was found in all Riyadh strains, while two unique substitutions (L38P, G233R) were recognized only in B/Vic-like Riyadh strains. Riyadh strains were also found to contain N-glycosylation site in HA gene of both B/Vic and B/Yam lineages at positions 197-199 (NET) and 196-198 (NNK/DNK), respectively. The significance of these mutations on the antigenicity of both lineages is discussed herein. The unique changes observed in HA and NA genes of influenza B Riyadh strains support strongly the need for continuous surveillance and monitoring of new evolving strains that might pose threat to the Saudi community.
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Affiliation(s)
- Ghazanfar Ali
- Center of Excellence in Biotechnology Research, King Saud University, Riyadh, Saudi Arabia
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15
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Burnham AJ, Baranovich T, Govorkova EA. Neuraminidase inhibitors for influenza B virus infection: efficacy and resistance. Antiviral Res 2013; 100:520-34. [PMID: 24013000 DOI: 10.1016/j.antiviral.2013.08.023] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/17/2013] [Accepted: 08/25/2013] [Indexed: 01/28/2023]
Abstract
Many aspects of the biology and epidemiology of influenza B viruses are far less studied than for influenza A viruses, and one of these aspects is efficacy and resistance to the clinically available antiviral drugs, the neuraminidase (NA) inhibitors (NAIs). Acute respiratory infections are one of the leading causes of death in children and adults, and influenza is among the few respiratory infections that can be prevented and treated by vaccination and antiviral treatment. Recent data has suggested that influenza B virus infections are of specific concern to pediatric patients because of the increased risk of severe disease. Treatment of influenza B is a challenging task for the following reasons: This review presents current knowledge of the efficacy of NAIs for influenza B virus and antiviral resistance in clinical, surveillance, and experimental studies.
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Affiliation(s)
- Andrew J Burnham
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
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Roy Mukherjee T, Mukherjee A, Mullick S, Chawla-Sarkar M. Full genome analysis and characterization of influenza C virus identified in Eastern India. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2013; 16:419-25. [PMID: 23523822 DOI: 10.1016/j.meegid.2013.02.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/18/2013] [Accepted: 02/22/2013] [Indexed: 11/22/2022]
Abstract
In tropical countries of Asia, like India, approximately 0.5 million children of <5 years of age die annually due to acute respiratory illness (ARI). Of common respiratory pathogens, influenza viruses (A & B) are associated with annual worldwide epidemics; while the information on influenza C virus is inadequate. During January 2011 through December 2012, 2737 nasal and/or throat swabs were collected from patients reporting at outpatient department of hospitals in eastern India with ARI. Nucleotide sequencing was carried out using gene specific primers followed by pair-wise sequence alignments, multiple alignments, construction of phylogenetic tree and analysis of deduced amino acid sequences. Study reveals that, out of 2737 samples, 1616 (59.04%) were positive for one or more respiratory viruses; of which 23.72% were positive for influenza A and B viruses. From influenza A & B negative samples, influenza C virus was screened and detected with a frequency of 0.18%. Phylogenetic analysis showed that the HE, matrix, NS, PB1 and PB2 gene of the studied strain (C/Eastern-India/1202/2011) possessed a close relatedness to C/Yamagata/26/81 like strains. The P3 gene shows proximity with C/Mississipi/80 like strains whereas NP gene revealed similarity with C/Miyagi/1/93 like strains. The outcome of the whole genome analysis of the strain C/Eastern-India/1202/2011 provided useful information regarding genetic diversity of influenza C strains in India.
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Lee HK, Tang JWT, Kong DHL, Koay ESC. Simplified large-scale Sanger genome sequencing for influenza A/H3N2 virus. PLoS One 2013; 8:e64785. [PMID: 23741393 PMCID: PMC3669369 DOI: 10.1371/journal.pone.0064785] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/18/2013] [Indexed: 01/03/2023] Open
Abstract
Background The advent of next-generation sequencing technologies and the resultant lower costs of sequencing have enabled production of massive amounts of data, including the generation of full genome sequences of pathogens. However, the small genome size of the influenza virus arguably justifies the use of the more conventional Sanger sequencing technology which is still currently more readily available in most diagnostic laboratories. Results We present a simplified Sanger-based genome sequencing method for sequencing the influenza A/H3N2 virus in a large-scale format. The entire genome sequencing was completed with 19 reverse transcription-polymerase chain reactions (RT-PCRs) and 39 sequencing reactions. This method was tested on 15 native clinical samples and 15 culture isolates, respectively, collected between 2009 and 2011. The 15 native clinical samples registered quantification cycle values ranging from 21.0 to 30.56, which were equivalent to 2.4×103–1.4×106 viral copies/µL of RNA extract. All the PCR-amplified products were sequenced directly without PCR product purification. Notably, high quality sequencing data up to 700 bp were generated for all the samples tested. The completed sequence covered 408,810 nucleotides in total, with 13,627 nucleotides per genome, attaining 100% coding completeness. Of all the bases produced, an average of 89.49% were Phred quality value 40 (QV40) bases (representing an accuracy of circa one miscall for every 10,000 bases) or higher, and an average of 93.46% were QV30 bases (one miscall every 1000 bases) or higher. Conclusions This sequencing protocol has been shown to be cost-effective and less labor-intensive in obtaining full influenza genomes. The constant high quality of sequences generated imparts confidence in extending the application of this non-purified amplicon sequencing approach to other gene sequencing assays, with appropriate use of suitably designed primers.
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Affiliation(s)
- Hong Kai Lee
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Molecular Diagnosis Centre, Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
| | - Julian Wei-Tze Tang
- Alberta Provincial Laboratory for Public Health, University of Alberta Hospital, Edmonton, Alberta, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Debra Han-Lin Kong
- Molecular Diagnosis Centre, Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
| | - Evelyn Siew-Chuan Koay
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Molecular Diagnosis Centre, Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
- * E-mail:
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Mukherjee TR, Agrawal AS, Chakrabarti S, Chawla-Sarkar M. Full genomic analysis of an influenza A (H1N2) virus identified during 2009 pandemic in Eastern India: evidence of reassortment event between co-circulating A(H1N1)pdm09 and A/Brisbane/10/2007-like H3N2 strains. Virol J 2012; 9:233. [PMID: 23057530 PMCID: PMC3576275 DOI: 10.1186/1743-422x-9-233] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 09/27/2012] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND During the pandemic [Influenza A(H1N1)pdm09] period in 2009-2010, an influenza A (Inf-A) virus with H1N2 subtype (designated as A/Eastern India/N-1289/2009) was detected from a 25 years old male from Mizoram (North-eastern India). OBJECTIVE To characterize full genome of the H1N2 influenza virus. METHODS For initial detection of Influenza viruses, amplification of matrix protein (M) gene of Inf-A and B viruses was carried out by real time RT-PCR. Influenza A positive viruses are then further subtyped with HA and NA gene specific primers. Sequencing and the phylogenetic analysis was performed for the H1N2 strain to understand its origin. RESULTS The outcome of this full genome study revealed a unique reassortment event where the N-1289 virus acquired it's HA gene from a 2009 pandemic H1N1 virus with swine origin and the other genes from H3N2-like viruses of human origin. CONCLUSIONS This study provides information on possibility of occurrence of reassortment events during influenza season when infectivity is high and two different subtypes of Inf-A viruses co-circulate in same geographical location.
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Affiliation(s)
| | - Anurodh S Agrawal
- National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Sekhar Chakrabarti
- National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Mamta Chawla-Sarkar
- National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
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Zhu N, Li P, Yu J, Li Y, Zhao J, Xia H, Tang S, Zhang Z, Kou Z, Yin S, Fan Z, Li T. Molecular characterization of influenza B viruses isolated in east-central China in 2009-2010. Virus Genes 2012; 46:28-38. [PMID: 23011776 DOI: 10.1007/s11262-012-0826-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 09/13/2012] [Indexed: 11/24/2022]
Abstract
The current circulating influenza B viruses can be divided into two major phylogenetic lineages: the Victoria and Yamagata lineages. We conducted a survey of influenza B viruses in Hubei and Zhejiang provinces during 2009-2010. Out of 341 throat swabs, 18 influenza B viruses were isolated. Five isolates were selected for genetic and phylogenetic analysis. The molecular analyses revealed that all the isolates had similar antigenic characteristics to B/Brisbane/60/2008. However, in the three viruses isolated from Zhejiang, a single asparagine to aspartic acid substitution in position 197 was observed, thereby eliminating the glycosylation at that site and possibly causing an antigenic change. None of the viruses had amino acid mutations at positions 116, 149, 152, 198, 222, 250, 291, and 402 of the neuraminidase (NA) gene, predicting that the viruses would still be sensitive to NA inhibitors. Phylogenetic analyses revealed that all five isolates were closely related to B/Brisbane/60/2008-the 2010 vaccine strain-and contained Victoria-like hemagglutinin and Yamagata-like NA genes, suggesting that reassortment may had occurred. In addition, similar phylogenetic patterns among the acidic polymerase, nucleoprotein and matrix protein genes, as well as between the basic polymerase 1 and basic polymerase 2 genes, were observed, suggesting possible functional interactions among these proteins. All the results highlighted the importance of molecular monitoring of influenza B viruses for reassortment and antigenic drift.
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Affiliation(s)
- Na Zhu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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