Reasonable Rascal
05-10-09, 10:11
INFLUENZA A (H1N1) - WORLDWIDE (17)
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A ProMED-mail post
Date: Fri 8 May 2009
From: Marcel Jonges
Travel-associated influenza A (H1N1) with a virus containing a mutation in PB2
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In the Netherlands, the 2nd laboratory confirmed human case of influenza A (H1N1) virus infection was reported on 7 May 2009. A 53-year-old woman returned on the 30 Apr 2009 from Cancun, Mexico. During the flight she developed an unproductive cough. Then, 2 days later on 2 May 2009, she had a temperature of 38.6C and a sore throat and consulted a general practitioner. Samples were submitted for diagnostic evaluation and both the patient and her husband were treated with oseltamivir. The patient recovered completely and uneventfully, and samples collected 4 days later tested negative. The virus was analyzed for presence of antiviral resistance markers in the neuraminidase and for human adaptation markers in the PB2 protein
by direct sequencing.
The sequence data suggested that the virus was susceptible to both oseltamivir and zanamivir. The amino acid 627 in PB2 (glutamicacid) was not human-host-adapted, similar to recent swine influenza A (H1N1) viruses. However, a glutamic acid to glycine amino acid substitution was detected at position 677 in PB2. This mutation was not observed in any of the A (H1N1) sequences submitted since 27 Apr 2009. Lam et al. (2008) postulated that this substitution could reflect adaptation to mammalian hosts of highly pathogenic avian influenza A (H5N1) viruses (1), as it was found to be under positive selection based on phylogenetics of Indonesian viruses. Based on the
position of the mutation it might contribute to more efficient human-to-human transmission by enhanced replicative efficiency of the polymerase of the influenza A (H1N1) virus in humans [PB2 is a polymerase component. - Mod.CP]. Experiments are underway to test the relevance of this finding.
Reference:
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(1) Lam TT, Hon CC, Pybus OG, Kosakovsky Pond SL, Wong RT, Yip CW, Zeng F, Leung FC, Evolutionary and transmission dynamics of reassortant H5N1 influenza virus in Indonesia, PLoS Pathog. 2008 Aug 22;4(8):e1000130.
[Byline: Marcel Jonges, Adam Meijer, Pieter Overduin, Titia Kortbeek, Rob van Kessel, Paul Bijkerk, Martin Schutten, Theo Bestebroer, Charles Boucher, Guus Rimmelzwaan, Ron Fouchier, Ab Osterhaus, and Marion Koopmans At the National Institute for Public Health and the Environment, Bilthoven, the Netherlands, and the Erasmus Medical Center, Rotterdam, the Netherlands]
--
Marcel.Jonges
National Institute for Public Health and the Environment
Centre for Infectious Disease Control
P.O. Box 1
3720 BA, Bilthoven
The Netherlands
[The identification of a single mutation in the PB2 gene (encoding the major component of the viral polymerase) of this Netherlands isolate of the novel 2009 strain of influenza A (H1N1) virus is an interesting finding only previously reported in the case of avian influenza A (H5N1) virus. It is conceivable that such a mutation might influence the transmissibility and the host range of the virus. However, it would be premature to draw such a conclusion since there
appears to have been no onward transmission of the virus to any other person. Nonetheless this is clearly a site which should be kept under surveillance in future studies. - Mod.CP]
[The Netherlands can be located on the HealthMap/ProMED-mail interactive map at: <http://healthmap.org/r/00by> -CopyEd.EJP]
***********************************
A ProMED-mail post
Date: Fri 8 May 2009
From: Marcel Jonges
Travel-associated influenza A (H1N1) with a virus containing a mutation in PB2
------------------------------------------------------------------------------
In the Netherlands, the 2nd laboratory confirmed human case of influenza A (H1N1) virus infection was reported on 7 May 2009. A 53-year-old woman returned on the 30 Apr 2009 from Cancun, Mexico. During the flight she developed an unproductive cough. Then, 2 days later on 2 May 2009, she had a temperature of 38.6C and a sore throat and consulted a general practitioner. Samples were submitted for diagnostic evaluation and both the patient and her husband were treated with oseltamivir. The patient recovered completely and uneventfully, and samples collected 4 days later tested negative. The virus was analyzed for presence of antiviral resistance markers in the neuraminidase and for human adaptation markers in the PB2 protein
by direct sequencing.
The sequence data suggested that the virus was susceptible to both oseltamivir and zanamivir. The amino acid 627 in PB2 (glutamicacid) was not human-host-adapted, similar to recent swine influenza A (H1N1) viruses. However, a glutamic acid to glycine amino acid substitution was detected at position 677 in PB2. This mutation was not observed in any of the A (H1N1) sequences submitted since 27 Apr 2009. Lam et al. (2008) postulated that this substitution could reflect adaptation to mammalian hosts of highly pathogenic avian influenza A (H5N1) viruses (1), as it was found to be under positive selection based on phylogenetics of Indonesian viruses. Based on the
position of the mutation it might contribute to more efficient human-to-human transmission by enhanced replicative efficiency of the polymerase of the influenza A (H1N1) virus in humans [PB2 is a polymerase component. - Mod.CP]. Experiments are underway to test the relevance of this finding.
Reference:
----------
(1) Lam TT, Hon CC, Pybus OG, Kosakovsky Pond SL, Wong RT, Yip CW, Zeng F, Leung FC, Evolutionary and transmission dynamics of reassortant H5N1 influenza virus in Indonesia, PLoS Pathog. 2008 Aug 22;4(8):e1000130.
[Byline: Marcel Jonges, Adam Meijer, Pieter Overduin, Titia Kortbeek, Rob van Kessel, Paul Bijkerk, Martin Schutten, Theo Bestebroer, Charles Boucher, Guus Rimmelzwaan, Ron Fouchier, Ab Osterhaus, and Marion Koopmans At the National Institute for Public Health and the Environment, Bilthoven, the Netherlands, and the Erasmus Medical Center, Rotterdam, the Netherlands]
--
Marcel.Jonges
National Institute for Public Health and the Environment
Centre for Infectious Disease Control
P.O. Box 1
3720 BA, Bilthoven
The Netherlands
[The identification of a single mutation in the PB2 gene (encoding the major component of the viral polymerase) of this Netherlands isolate of the novel 2009 strain of influenza A (H1N1) virus is an interesting finding only previously reported in the case of avian influenza A (H5N1) virus. It is conceivable that such a mutation might influence the transmissibility and the host range of the virus. However, it would be premature to draw such a conclusion since there
appears to have been no onward transmission of the virus to any other person. Nonetheless this is clearly a site which should be kept under surveillance in future studies. - Mod.CP]
[The Netherlands can be located on the HealthMap/ProMED-mail interactive map at: <http://healthmap.org/r/00by> -CopyEd.EJP]