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Return of pandemic H1N1 influenza virus.

Sherbany H, McCauley J, Meningher T, Hindiyeh M, Dichtiar R, Markovich MP, Mendelson E, Mandelboim M - BMC Infect. Dis. (2014)

Bottom Line: Surprisingly, however in 2012-2013, we noticed that the percentages of patients hospitalized due to the pandemic H1N1 influenza infection increased significantly.Moreover, the ages of hospitalized patients differed throughout this entire period (2009-2013) and pregnant women were especially vulnerable to the infection.High percentages of patients (especially pregnant women) were hospitalized in 2013 due to the A(H1N1)pdm09 infection, which may have been enabled by an antigenic drift from those which circulated at the onset of the pandemic.

View Article: PubMed Central - PubMed

Affiliation: Central Virology Laboratory, Ministry of Health, Public Health Services, Chaim Sheba Medical Center, Tel Hashomer, Ramat-Gan, Israel. hilda.sherbany@sheba.health.gov.il.

ABSTRACT

Background: Influenza pandemics are usually caused by the re-assortment of several influenza viruses, results in the emergence of new influenza virus strains that can infect the entire population. These pandemic strains, as well as seasonal influenza viruses, are subjected to extensive antigenic change that has, so far, prevented the generation of a universal vaccine.

Methods: Samples of patients hospitalized due to infection with the pandemic H1N1 influenza virus (A(H1N1)pdm09) from 2009, when the virus first appeared, until 2013 were analyzed.

Results: While many patients were hospitalized in 2009 due to infection with the pandemic H1N1 influenza virus, only small percentages of patients were hospitalized later in 2010-2012. Surprisingly, however in 2012-2013, we noticed that the percentages of patients hospitalized due to the pandemic H1N1 influenza infection increased significantly. Moreover, the ages of hospitalized patients differed throughout this entire period (2009-2013) and pregnant women were especially vulnerable to the infection.

Conclusions: High percentages of patients (especially pregnant women) were hospitalized in 2013 due to the A(H1N1)pdm09 infection, which may have been enabled by an antigenic drift from those which circulated at the onset of the pandemic.

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Phylogenetic tree. Phylogenetic tree was generated using the primers listed in Table 1. The HA genes of H1N1 viruses cluster into eight genetic groups defined by amino acid substitution in HA1. The numbers indicate the different subgroups of the pandemic influenza viruses. Mutations are indicated.
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Fig5: Phylogenetic tree. Phylogenetic tree was generated using the primers listed in Table 1. The HA genes of H1N1 viruses cluster into eight genetic groups defined by amino acid substitution in HA1. The numbers indicate the different subgroups of the pandemic influenza viruses. Mutations are indicated.

Mentions: The differences in the ages of the hospitalized patients observed throughout the years and the rebound of the A(H1N1)pdm09 virus infection observed in 2012–13, led us to hypothesize that the A(H1N1)pdm09 virus had undergone changes during this short period. Several influenza viruses were isolated from the samples collected during these years, to amplify their hemagglutinin gene using the primers described in Table 1. The obtained sequences were used to build a phylogenetic tree. Viruses isolated in 2009 and in 2013 diverged differently in the phylogenetic tree (Figure 5). While the influenza strains obtained in 2009 resemble the strain used for the influenza vaccine of that year, those who were isolated in 2011–13 resembled other strains, in particular, group 6 viruses.Figure 5


Return of pandemic H1N1 influenza virus.

Sherbany H, McCauley J, Meningher T, Hindiyeh M, Dichtiar R, Markovich MP, Mendelson E, Mandelboim M - BMC Infect. Dis. (2014)

Phylogenetic tree. Phylogenetic tree was generated using the primers listed in Table 1. The HA genes of H1N1 viruses cluster into eight genetic groups defined by amino acid substitution in HA1. The numbers indicate the different subgroups of the pandemic influenza viruses. Mutations are indicated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4375933&req=5

Fig5: Phylogenetic tree. Phylogenetic tree was generated using the primers listed in Table 1. The HA genes of H1N1 viruses cluster into eight genetic groups defined by amino acid substitution in HA1. The numbers indicate the different subgroups of the pandemic influenza viruses. Mutations are indicated.
Mentions: The differences in the ages of the hospitalized patients observed throughout the years and the rebound of the A(H1N1)pdm09 virus infection observed in 2012–13, led us to hypothesize that the A(H1N1)pdm09 virus had undergone changes during this short period. Several influenza viruses were isolated from the samples collected during these years, to amplify their hemagglutinin gene using the primers described in Table 1. The obtained sequences were used to build a phylogenetic tree. Viruses isolated in 2009 and in 2013 diverged differently in the phylogenetic tree (Figure 5). While the influenza strains obtained in 2009 resemble the strain used for the influenza vaccine of that year, those who were isolated in 2011–13 resembled other strains, in particular, group 6 viruses.Figure 5

Bottom Line: Surprisingly, however in 2012-2013, we noticed that the percentages of patients hospitalized due to the pandemic H1N1 influenza infection increased significantly.Moreover, the ages of hospitalized patients differed throughout this entire period (2009-2013) and pregnant women were especially vulnerable to the infection.High percentages of patients (especially pregnant women) were hospitalized in 2013 due to the A(H1N1)pdm09 infection, which may have been enabled by an antigenic drift from those which circulated at the onset of the pandemic.

View Article: PubMed Central - PubMed

Affiliation: Central Virology Laboratory, Ministry of Health, Public Health Services, Chaim Sheba Medical Center, Tel Hashomer, Ramat-Gan, Israel. hilda.sherbany@sheba.health.gov.il.

ABSTRACT

Background: Influenza pandemics are usually caused by the re-assortment of several influenza viruses, results in the emergence of new influenza virus strains that can infect the entire population. These pandemic strains, as well as seasonal influenza viruses, are subjected to extensive antigenic change that has, so far, prevented the generation of a universal vaccine.

Methods: Samples of patients hospitalized due to infection with the pandemic H1N1 influenza virus (A(H1N1)pdm09) from 2009, when the virus first appeared, until 2013 were analyzed.

Results: While many patients were hospitalized in 2009 due to infection with the pandemic H1N1 influenza virus, only small percentages of patients were hospitalized later in 2010-2012. Surprisingly, however in 2012-2013, we noticed that the percentages of patients hospitalized due to the pandemic H1N1 influenza infection increased significantly. Moreover, the ages of hospitalized patients differed throughout this entire period (2009-2013) and pregnant women were especially vulnerable to the infection.

Conclusions: High percentages of patients (especially pregnant women) were hospitalized in 2013 due to the A(H1N1)pdm09 infection, which may have been enabled by an antigenic drift from those which circulated at the onset of the pandemic.

Show MeSH
Related in: MedlinePlus