scholarly journals Local spread of influenza A (H1N1) viruses without a mutation for the maximum duration of an epidemic season in Japan

Author(s):  
Akeno Tsuneki-Tokunaga ◽  
Takanori Kondo ◽  
Kyosuke Kanai ◽  
Asao Itagaki ◽  
Hideaki Tsuchie ◽  
...  
2021 ◽  
Author(s):  
Seiji Kageyama ◽  
Akeno Tsuneki-Tokunaga ◽  
Kyosuke Kanai

Abstract Close observation of the local transmission of influenza A(H1N1) viruses enabled an estimation of the transmission period of the virus without a mutation. Of 4,448 isolates from 11 consecutive years, 237 isolates could be categorized into 57 strain groups with identical hemagglutinin genes. Transmission of these 57 strains was chased for the maximum duration of an epidemic season. In addition, 35 identical strains were recognized at the study site and other countries within 147 days. Consequently, it can be postulated that once an influenza virus enters a temperate country, the strain rarely mutates until the end of the season.


2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Petri Jalovaara ◽  
Polina Mishel ◽  
Hannimari Kallio-Kokko ◽  
Miia Valkonen ◽  
Anu Kantele ◽  
...  

Author(s):  
O. Smutko ◽  
L. Radchenko ◽  
A. Mironenko

The aim of the present study was identifying of molecular and genetic changes in hemaglutinin (HA), neuraminidase (NA) and non-structure protein (NS1) genes of pandemic influenza A(H1N1)pdm09 strains, that circulated in Ukraine during 2015-2016 epidemic season. Samples (nasopharyngeal swabs from patients) were analyzed using real-time polymerase chain reaction (RTPCR). Phylogenetic trees were constructed using MEGA 7 software. 3D structures were constructed in Chimera 1.11.2rc software. Viruses were collected in 2015-2016 season fell into genetic group 6B and in two emerging subgroups, 6B.1 and 6B.2 by gene of HA and NA. Subgroups 6B.1 and 6B.2 are defined by the following amino acid substitutions. In the NS1 protein were identified new amino acid substitutions D2E, N48S, and E125D in 2015-2016 epidemic season. Specific changes were observed in HA protein antigenic sites, but viruses saved similarity to vaccine strain. NS1 protein acquired substitution associated with increased virulence of the influenza virus.


2017 ◽  
Vol 88 ◽  
pp. 12-16 ◽  
Author(s):  
Rakefet Pando ◽  
Yaron Drori ◽  
Nehemya Friedman ◽  
Aharona Glatman-Freedman ◽  
Hanna Sefty ◽  
...  

2020 ◽  
pp. 26-28
Author(s):  
I. A. Malchikov ◽  
A. V. Slobodenyuk ◽  
I. V. Vyalykh ◽  
A. Yu. Markaran ◽  
Yu. V. Grigorieva ◽  
...  

Donor blood serum was tested to detect antibodies against circulating influenza viruses. The titer of specific antibodies was determined in the hemagglutination inhibition test (RTGA) against influenza viruses A/California/07/09(H1N1) pdm09, A/HongKong/4801/14(H3N2) and B/Brisben/46/15. In the pre-epidemic period 2018–2019, the immune layer of people with conditionally protective titers of antiviral antibodies was detected in terms of the lowest to A(H3N2) virus (50.0 %), the highest to influenza B (85.4 %). In the post-epidemic season of 2018–2019, the immune layer to influenza A(H1N1) pdm09 virus did not change significantly, which could indicate the preservation of the activity of this virus in the adult population; an increase in the immune layer of individuals with protective titers of antibodies to influenza A(H3N2) – 67.4 % and a decrease in influenza B virus – 49.2 %. A comparison of the results of laboratory data carried out in the pre- and post-epidemic seasons revealed significant differences in the number of people with average antibody titers against influenza A(H3N2) and B viruses (p < 0.05).


2019 ◽  
Vol 11 (1) ◽  
pp. 71-75
Author(s):  
S. M. Bezrodnova ◽  
N. A. Yatsenko ◽  
O. O. Kravchenko ◽  
Sh. M. Khurtsilava

Objective: to study the clinical and epidemiological features of influenza in children in the Stavropol Territory.Materials and methods: influenza prevalence is analyzed from 2015 to 2017 the paper used the data from the Territorial Rospotrebnadzor in the Stavropol Territory. We used the following methods: bibliographic, monographic description, epidemiological, analytical, statistical methods.Results: Among the deciphered acute respiratory viral infections, the specific gravity of influenza A (H1N1) 09 in 2016 reached 78%, and in 2017 influenza B prevailed – in 57,4% of children, and influenza A (H3N2) – in 42,6% of cases. In 2016 68,5% of children under 6 years of age, of all admitted, were hospitalized, and in 2017 – 83,86%. We presented the peculiarities of the course of influenza in different epidemic seasons.Conclusion: Unvaccinated children up to 6 years of age have the disease mainly in severe forms and with complications. The epidemic period began to increase in 2015–2016 at week 52, and in 2016–2017 from week 48, ended at week 13 and at week 17. At the epidemic of 2015–2016, intoxication syndrome with chills, microcirculation disturbance, catarrhal syndrome, ARDS prevailed in the clinical picture. The epidemic season of 2016–2017 was characterized by intoxication syndrome, encephalic reaction, hemorrhagic and myalgic syndromes.


2016 ◽  
Vol 88 (11) ◽  
pp. 112-120 ◽  
Author(s):  
D K Lvov ◽  
L V Kolobukhina ◽  
E I Burtseva ◽  
I S Kruzhkova ◽  
N A Malyshev ◽  
...  

In the 2015—2016 epidemic season, there were dominant influenza A(H1N1)pdm09 strains (over 90%) among the circulating influenza viruses in most countries of the Northern Hemisphere and in Russia. A study of the antigenic properties of influenza A(H1N1)pdm09 strains revealed no differences in those of vaccine virus. Sequencing showed that there were amino acid substitutions in hemagglutinin (receptor binding and Sa sites) and in the genes encoding internal proteins (PA, NP, M1, and NS1). The rise in the incidence in the Russian Federation, which was etiologically associated with influenza viruses, was registered in January-February 2016 with its maximum being observed at 4—5 weeks of 2016. Within the framework of the epidemiological surveillance of circulating influenza viruses in the Russian Federation, which was conducted by the WHO European Office, the D.I. Ivanovsky Institute of Virology, Honorary Academician N.F. Gamaleya Federal Research Centre for Epidemiology and Microbiology, Ministry of Health of Russia, and the Research Institute of Influenza, Ministry of Health of Russia, monitored at the Infectious Diseases Hospital One (IDH-1), Moscow Healthcare Department. Among 1491 examinees, influenza was verified in 104 (21.3%) adults, 208 (42.5%) pregnant women, and 177 (36.2%) children. Influenza A(H1N1)pdm09 was more often diagnosed in the age group of 15—40 years (63.7%); the proportion of influenza patients aged over 50 years increased (22.1%). Most adult patients had moderate influenza; pneumonia complicated the disease in 27.4%. Influenza in the pregnant women was complicated by pneumonia in 4.8% of cases. Influenza was more frequently diagnosed in infants and preschool children aged 0 to 3 years (42.9%), 4 to 6 years (41.2%), and older (15.9%), namely: 7—9 years (10%) and 10—12 years (5.9%). Influenza in the children was complicated by acute tonsillitis (19.4%) and varying degrees of laryngeal stenosis (12.4%). Bronchial obstructive syndrome developed in 2.5%, the rate of pneumonia was 6.2%. Antiviral therapy (AVT) in the early stages of the disease reduces the risk of its severity, the frequency of secondary complications, and the duration and degree of clinical symptoms of influenza. AVT with oseltamivir, zanamivir, imidazolyl ethanamide pentandioic acid (ingavirin), and interferon-a2b (viferon) has been performed in the patients hospitalized at Moscow IDH-1 in the 2015—2016 epidemic season.


2014 ◽  
Vol 23 ◽  
pp. 95-98 ◽  
Author(s):  
Fabio Tramuto ◽  
Carmelo Massimo Maida ◽  
Francesco Magliozzo ◽  
Emanuele Amodio ◽  
Francesco Vitale

2014 ◽  
Vol 19 (27) ◽  
Author(s):  
U Perez-Sautu ◽  
F Pozo ◽  
I Cuesta ◽  
S Monzon ◽  
A Calderon ◽  
...  

The Y155H amino acid substitution in the neuraminidase gene (NA) has previously been associated with highly reduced inhibition by neuraminidase inhibitors in the seasonal H1N1 influenza A virus which circulated in humans before the 2009 pandemic. During the 2012/13 epidemic season in Spain, two A(H1N1)pdm09 viruses bearing the specific Y155H substitution in the NA were detected and isolated from two patients diagnosed with severe respiratory syndrome and pneumonia requiring admission to the intensive care unit. Contrary to what was observed in the seasonal A(H1N1) viruses, neither of the Y155H A(H1N1)pdm09 viruses described here showed a phenotype of reduced inhibition by NAIs as determined by the neuraminidase enzyme inhibition assay (MUNANA). High-throughput sequencing of the NA of both Y155H viruses showed that they were composed to >99% of H155 variants. We believe that this report can contribute to a better understanding of the biological significance of amino acid substitutions in the neuraminidase protein with regard to susceptibility of influenza viruses to neuraminidase inhibitors. This is of critical importance for optimal management of influenza disease patients.


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