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Pandemic (H1N1) 2009 - update 101
Weekly update
21.05.2010

As of 16 May, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18097 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

The current situation is largely unchanged since the last update. The most active areas of pandemic influenza virus transmission currently are in parts of the Caribbean and Southeast Asia. In the temperate zone of the northern and southern hemisphere, overall pandemic influenza activity remains low to sporadic. In central Africa, there has been increased transmission of seasonal influenza type B viruses, accounting for 85% of all influenza isolates in the region. Influenza B also continues to be detected at low levels across parts of Asia and Europe, and has now been reported in Central America. [...]

[...] In Sub-Saharan Africa, limited data from several countries suggest that active transmission of pandemic influenza virus in West Africa has now largely subsided. In Ghana, 6% of respiratory samples tested positive for pandemic influenza virus during the most recent reporting week. Across the rest of region, the pandemic influenza virus continues to be detected sporadically or at low levels, most recently in Angola and Rwanda. Sporadic detections of seasonal influenza H3N2 and influenza B viruses have been reported in western, central Africa and to a lesser extent southern Africa ... mehr

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Birgitt

INFLUENZA PANDEMIC (H1N1) (34): INDIAN VARIANTS
***********************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Tue 25 May 2010
Source: The Times of India, Pune [edited]
<http://timesofindia.indiatimes.com/City ... 970862.cms?>

The National Institute of Virology (NIV) here has detected 3 new
variants of the H1N1 virus. Fortunately, all 3 variants have shown
susceptibility to Tamiflu, the drug used in the treatment of swine
flu. However, with the virus actively acquiring new properties, NIV
scientists are apprehensive that it might develop resistance to the
medicines used in treating swine flu. "For now, there is no need to
worry. But we are closely monitoring the virus for any change in its
virulence," NIV assistant director Sarah Cherian told the Times of
India recently.

Cherian said 7 mutated variants of the virus have been found across
the world so far. "As expected of the seasonal influenza virus, the
H1N1 virus is also going through constant genetic variations which
might lead to significant changes in its antiviral resistance," she
said.

The variants of the H1N1 virus, representing both recovered and fatal
cases from major cities -- Pune, Mumbai, Delhi, Hyderabad and
Bangalore -- were analysed at the NIV, and the complete genomes of
these variants were sequenced. The results of the genetic analysis
have been published in the March 2010 issue of the US journal, PLOS
One.

The NIV study, which compared the Indian viruses with 685 whole
genomes of global viral isolates, revealed that the 1st Indian
isolate of May 2009 belonged to a subtype (clade 5) and correlated to
the time during which the dissemination of the virus was noted in
Asia.

The later isolates of the period from June to September 2009 belonged
to H1N1 variants (clades 6 and 7). The clade 7 variant was seen to be
the dominant one, though no spatio-temporal patterns were noted
within this variant, said Cherian. Among the established pathogenic
markers, no significant change was observed in the Indian variants of
the H1N1 virus.

The 1st influenza pandemic of the 21st century was declared with the
emergence of a novel influenza A (H1N1) strain in Mexico and the US
in April 2009. In its last H1N1 situation update released on 14 May
2010, the World Health Organisation said that more than 214 countries
and overseas territories or communities have reported
laboratory-confirmed cases of pandemic influenza H1N1 2009, including
over 18 036 deaths. [The most recent WHO Weekly Update (101), dated
24 May 2010 has been archived in ProMED-mail as "Influenza pandemic
(H1N1) (33): WHO update 20100522.1700." - Mod.CP]

--
Communicated by:
ProMED-mail Rapporteur Mary Marshall

[The detection of 3 genetic variants circulating in India is an
interesting observation. For the benefit of readers wishing more
precise detail, the abstract of the PLoS ONE paper is posted below.

"Title: Genetic Characterization of the Influenza A Pandemic (H1N1)
2009 Virus Isolates from India. Reference: PLoS ONE 5(3): e9693.
doi:10.1371/journal.pone.0009693
<http://www.plosone.org/article/info%3Ad ... ne.0009693>.
By: Varsha A. Potdar, Mandeep S. Chadha, Santosh M. Jadhav, Jayati
Mullick, Sarah S. Cherian, Akhilesh C. Mishra At: National Institute
of Virology, Pune, India.

Abstract
Background: The influenza A pandemic H1N1 2009 (H1N1pdm) virus
appeared in India in May 2009 and thereafter, outbreaks with
considerable morbidity and mortality have been reported from many
parts of the country. Continuous monitoring of the genetic makeup of
the virus is essential to understand its evolution within the country
in relation to global diversification and to track the mutations that
may affect the behavior of the virus.

Methods: H1N1pdm viruses were isolated from both recovered and fatal
cases representing major cities and sequenced. Phylogenetic analyses
of 6 concatenated whole genomes and the hemagglutinin (HA) gene of 7
more isolates from May-September 2009 were performed with reference
to 685 whole genomes of global isolates available as of 24 Nov 2009.
Molecular characterization of all the 8 segments was carried out for
known pathogenic markers.

Results: The 1st isolate of May 2009 belonged to clade 5. Although
clade 7 was the dominant H1N1pdm lineage in India, both clades 6 and
7 were found to be co-circulating. The neuraminidase of all the
Indian isolates possessed H275, the marker for sensitivity to the
neuraminidase inhibitor oseltamivir [The H275Y mutation confers
resistance. - Mod.CP]. Some of the mutations in HA are at or in the
vicinity of antigenic sites and may, therefore, be of possible
antigenic significance. Among these, a D222G mutation in the HA
receptor binding domain was found in 2 of the 8 Indian isolates
obtained from fatal cases.

Conclusions: The majority of the 13 Indian isolates grouped in the
globally most widely circulating H1N1pdm clade 7. Further,
correlations of the mutations specific to clade 7 Indian isolates to
viral fitness and adaptability in the country remains to be
understood. The D222G mutation in HA from isolates of fatal cases
needs to be studied for pathogenicity."

The following information is relevant to these findings. In the
ProMED- mail post archived as "Influenza pandemic (H1N1) (21):
Norway, D222G mutation 20100305.0729," an analysis of Norwegian data
suggested that a correlation might exist between presence of the
D222G substitution in the HA gene and a severe clinical outcome,
reflecting an increase in pathogenicity caused by this mutation,
perhaps as a consequence of a change in cellular tropism rendering
the virus more pneumotropic. Alternatively, it is possible that the
likelihood of such mutations arising is higher in patients who fail
to fight off the virus rapidly and have virus already colonising the
lower respiratory tract.

Regarding the H275Y oseltamivir resistance mutation in the NA gene,
according to the most recent WHO update of 12 May 2010, the global
cumulative total is 289 so far. All but one of these have the H275Y
substitution and are assumed to remain sensitive to zanamivir. This
mutation was not present in the Indian isolates.

The HealthMap/ProMED-mail interactive map of India at
<http://healthmap.org/r/008o> can be used to locate the various
cities and states mentioned in this post. - Mod.CP]

Pandemic (H1N1) 2009 - update 102
Weekly update
28.05.2010 - WHO

As of 23 May, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18114 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

The most active areas of pandemic influenza virus transmission currently are in parts of the Caribbean and Southeast Asia, where low level circulation is occurring. Except for localized areas of pandemic influenza activity in parts of Chile, there is little evidence of pandemic influenza activity in the temperate zone of the southern hemisphere. Of note, Respiratory Syncitial Virus (RSV) is widely circulating in South America resulting in an increase in respiratory disease activity, complicating somewhat the interpretation of syndromic surveillance data from the area. RSV primarily affects children under the age of 5 years. Seasonal influenza A viruses continue to be detected at low to sporadic levels in all regions. Influenza B has been reported in increasing but low numbers in South America, where it only recently appeared, while it is decreasing in Asia [...]

[...] In Sub-Saharan Africa, limited data from several countries continues to suggest that active transmission of pandemic influenza virus in West Africa has now largely subsided. In addition to the persistence of low level circulation of pandemic influenza virus in Ghana, sporadic detections of pandemic influenza virus have been reported during the past month in Cameroon, Angola, and Rwanda. In Cameroon, there has been persistent active circulation of seasonal influenza B viruses since mid-March 2010 ... mehr

Gruß
Birgitt

Pandemic (H1N1) 2009 - update 103
Weekly update
04.06.2010

As of 30 May, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18138 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Active but declining transmission of pandemic influenza virus continued to be detected in parts of the Caribbean and Southeast Asia. In the countries of temperate southern hemisphere there is no evidence yet to suggest that the winter influenza season has begun, however there has been limited localized pandemic influenza virus transmission in Chile. In the rest of the world, overall pandemic influenza virus transmission remains low. Seasonal influenza B viruses are currently the predominant type of influenza virus circulating globally, although at low levels. Of note, during the later part of May 2010, low but significant levels of predominantly seasonal influenza H3N2 viruses have been detected in several countries of East Africa [...]

[...] In Sub-Saharan Africa, active but declining levels of pandemic influenza virus transmission continue to be detected in parts of West Africa, most notably in Ghana. During the most recent reporting week, 15% of all respiratory samples tested positive for pandemic influenza virus in Ghana. Sporadic detections of seasonal influenza B continue to be reported in central Africa. Of note, low but significant numbers of seasonal H3N2 viruses were recently detected in Kenya (6 of 57 respiratory samples tested) and Tanzania (13 of 25 respiratory samples tested) during the most recent reporting week ... mehr

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Birgitt

Pandemic (H1N1) 2009 - update 104
Weekly update
11.06.2010

As of 6 June, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18156 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Active but declining transmission of pandemic influenza virus persists in limited areas of the tropics, particularly in Southeast Asia and the Caribbean. As countries of the temperate southern hemisphere enter winter, only sporadic influenza activity has been detected so far, except in Chile and Uruguay, both of which have recently reported small numbers of pandemic influenza virus detections. Although seasonal influenza B viruses have been the predominant type of influenza virus circulating worldwide since the end of February 2010, there have been increasing but low level detections of seasonal influenza H3N2 viruses, particularly in South America and in East Africa [...]

In Sub-Saharan Africa, pandemic influenza virus continued to circulate at low levels in parts of West Africa, most notably in Ghana. During the most recent reporting week, 13% of all respiratory samples tested positive for pandemic influenza virus in Ghana. Small but significant numbers of seasonal H3N2 viruses have been detected in Kenya and Tanzania since late May 2010 ... mehr

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Birgitt

Pandemic (H1N1) 2009 - update 105
Weekly update
18.06.2010 - WHO

As of 13 June, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18172 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

The situation remains largely unchanged since the last update. Overall pandemic influenza activity remains low worldwide with geographically limited circulation of pandemic influenza virus in parts of the tropics, particularly in parts of Central America and the Caribbean and in parts of South and Southeast Asia. Seasonal influenza type B viruses continue to circulate at low levels across Asia and to a lesser extent across parts of Africa and South America. Recently re-emerged seasonal influenza H3N2 viruses continue to circulate in East Africa. As countries of the temperate southern hemisphere enter winter, overall only sporadic influenza activity has been detected so far [...]

[...] In Sub-Saharan Africa, pandemic influenza virus continued to circulate at low levels in limited areas of East and West Africa. During the first week of June 2010, 10% and 16% of all respiratory samples tested positive for pandemic influenza virus in Tanzania and Ghana, respectively. Small but significant numbers of seasonal H3N2 viruses continue to be been detected in Kenya and Tanzania since late May 2010 ... mehr

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Birgitt

Pandemic (H1N1) 2009 - update 106
Weekly update
25.06.2010

As of 20 June, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18209 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Worldwide, overall pandemic and seasonal influenza activity remains low. Active transmission of pandemic influenza virus persists in parts of the tropics, particularly in the Caribbean, West Africa, and South and Southeast Asia. Pandemic and seasonal influenza viruses have been detected only sporadically during the early part of winter in the temperate regions of the southern hemisphere. Global circulation of seasonal influenza virus type B viruses has declined substantially and persists at low levels in parts of East Asia, Central Africa, and Central America. During the past month, seasonal influenza H3N2 viruses have been detected at low levels across parts of East Africa and South America.

[...] In sub-Saharan Africa, pandemic and seasonal influenza activity has been limited to several countries. Ghana, in West Africa, continued to have active circulation of pandemic influenza virus long after overall activity peaked during early April 2010; the proportion of respiratory samples testing positive for pandemic influenza virus increased from 16% to 23% during the first two weeks of June 2010. Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, most notably in Cameroon. As reported in previous updates, small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern Africa; the most recent detections have been reported in Ghana, Kenya, and South Africa during the second week of June 2010. The persistence of H3N2 in this area over time very likely represents sustained community transmission of the virus ... mehr

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Birgitt

Pandemic (H1N1) 2009 - update 107
Weekly update
02.07.2010

As of 27 June, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18239 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Summary: Worldwide, overall pandemic and seasonal influenza activity remains low. In the temperate regions of the Southern Hemisphere, Chile, and Argentina report low activity and only sporadic detections of both pandemic and seasonal influenza viruses during the early part of winter. South Africa, New Zealand, and Australia have all recently noted slight increases in the rate of respiratory disease. South Africa recently reported their first case of confirmed H1N1; however, the predominant influenza virus there currently is seasonal influenza A(H3N2). The H3N2 virus detected in South Africa is similar to the Perth-like strain, which is currently a component of the trivalent seasonal influenza vaccine. Active transmission of pandemic influenza virus still persists in localized areas of the tropics, particularly in South and Southeast Asia, the Caribbean and West Africa. During the last 2 to 3 weeks, seasonal influenza H3N2 viruses have also been detected at increasing levels in Nicaragua, and low levels or sporadically in Australia, Central America, South Africa and East Africa. Global circulation of seasonal influenza virus type B viruses persists at low levels in parts of East Asia, Central Africa, and Central America.

Regional Details: [...] In sub-Saharan Africa, pandemic and seasonal influenza activity has been observed in several countries. Ghana, in West Africa, continues to have active circulation of pandemic influenza virus several weeks after activity peaked during early April 2010. Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, most notably in Cameroon. As reported in previous updates, small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern Africa; the most recent detections have been reported in Ghana, Kenya, and South Africa during mid June 2010. The persistence of H3N2 in this area over time very likely represents sustained community transmission of the virus ... mehr

Gruß
Birgitt

Pandemic (H1N1) 2009 - update 108
Weekly update
09.07.2010 - WHO

As of 4 July, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18311 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Worldwide, overall pandemic influenza activity remains low. Active circulation of pandemic influenza virus persists in areas of the tropics, particularly in South and Southeast Asia, the Caribbean and West Africa. Overall pandemic and seasonal influenza activity has remained low during the early part of the current winter season in the temperate zone of the southern hemisphere. Low levels of seasonal influenza (H3N2 and type B) viruses were detected during June 2010 in South Africa, while Chile, Australia, and New Zealand, have all recently detected low levels of predominantly pandemic influenza virus. Increasing seasonal influenza activity has also recently been observed in several countries of Central America.

[...] In sub-Saharan Africa, the current situation is largely unchanged since the last update. Pandemic and seasonal influenza activity continues to be observed in several countries. Ghana, in West Africa, continues to have active circulation of pandemic influenza virus several months after activity peaked during early April 2010. Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, particularly in Cameroon. Small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern Africa; the most recent detections have been reported in Kenya and South Africa ... mehr

Gruß
Birgitt

Pandemic (H1N1) 2009 - update 109
Weekly update
16.07.2010 - WHO

As of 12 July, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18337deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Worldwide, overall pandemic influenza activity remains low. The most active areas of pandemic influenza virus transmission currently are in parts of South Asia, West Africa, and Central America. In the temperate zone of the southern hemisphere, pandemic and seasonal influenza activity has remained low during the first half of the southern hemisphere winter, except in South Africa, where increased detections of primarily seasonal influenza viruses (type B and H3N2) were reported during late June and early July 2010. Seasonal influenza H3N2 viruses continue to circulate at varying levels across parts of the Americas, Africa, and Southeast Asia. Increased seasonal influenza activity continues to be observed in several countries of Central America.

[...] In sub-Saharan Africa, the current situation is largely unchanged since the last update. Pandemic and seasonal influenza activity continues to be observed in several countries. Ghana, in West Africa, continued to have a sustained resurgence in circulation of pandemic influenza virus during June 2010, more than several months after the first period of pandemic activity peaked (early April 2010). Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, particularly in Cameroon, where an increase in influenza type B virus circulation was observed during June 2010. Small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern and southern Africa; the most recent detections have been reported in Kenya and South Africa ... mehr

Gruß
Birgitt

Pandemic (H1N1) 2009 - update 110
Weekly update
23.07.2010 - WHO

As of 18 July 2010, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18366 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and member states and through monitoring of multiple sources of information.

Situation update:

Globally pandemic influenza activity remains low. The most active areas of influenza transmission remained in the tropical zones; primarily in West Africa, Central America, the Caribbean, and South and Southeast Asia, although activity is localized to relatively small areas in each region. In the temperate zone of the southern hemisphere, Australia and New Zealand have showed signs of increased respiratory disease in recent weeks. Both countries have continued to detect low levels of predominantly pandemic H1N1 influenza virus. In South Africa, the influenza season is well under way and is predominantly associated with seasonal influenza B and H3N2 viruses and small numbers of pandemic H1N1 influenza viruses.

[...] In sub-Saharan Africa, the current situation was largely unchanged since the last update. Pandemic H1N1 and seasonal influenza activity continued to be observed in several countries. Ghana has had a sustained circulation of pandemic H1N1 influenza virus since June 2010. Small numbers of seasonal influenza H3N2 viruses continued to be detected in eastern Africa ... mehr

Gruß
Birgitt

Pandemic (H1N1) 2009 - update 111
Weekly update
30.07.2010 - WHO

As of 25 July 2010, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18398 deaths. WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and member states and through monitoring of multiple sources of information.

Situation update:

Summary: Worldwide, overall pandemic and seasonal influenza activity remains low. In the southern hemisphere (where the winter season is in progress), current influenza activity remains variable: ranging from low and stable activity in Chile and Argentina, to low but increasing activity in Australia and New Zealand, to elevated and recently peaked activity in South Africa. Significant seasonal and pandemic influenza virus transmission continues to be detected at variable levels across parts of the tropics, particularly in several countries of the Americas and South and Southeast Asia.

[...] In sub-Saharan Africa (excluding South Africa), limited data indicate that seasonal influenza H3N2 and B viruses continued to circulate in parts of eastern Africa (Kenya) and central Africa (Cameroon), respectively. Ghana, in West Africa, reported sustained transmission of pandemic influenza virus during June and early July 2010 ... mehr

Gruß
Birgitt

INFLUENZA PANDEMIC (H1N1) (62): HUMAN ADAPTATION
************************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>


[1]
Date: Thu 5 Aug 2010
Source: Bloomberg Business Week [edited]
<http://www.businessweek.com/lifestyle/c ... 41737.html>


What Caused 2009 H1N1 Pandemic?
-------------------------------
Researchers say they've identified biochemical process behind 'swine flu'
-------------------------------------------------------------------------
The [pandemic] 2009 H1N1 swine flu virus used a new biochemical trick
to hijack host cells, a feat that triggered the recent pandemic,
according to an international team of scientists. "We have found why
the pandemic H1N1 virus replicated so well in humans," Yoshihiro
Kawaoka, a leading influenza expert and a professor of
pathobiological sciences at the University of Wisconsin-Madison's
School of Veterinary Medicine, said in a university news release [see
(2) below].

The H1N1 virus is a combination of 4 different avian and swine flu
viruses that emerged over the past 90 years. It also includes genetic
residue of the 1918 pandemic virus that killed as many as 20 million
people, Kawaoka explained.

A typical flu virus requires the presence of two amino acids --
lysine and asparagine -- in specific sites on a key avian protein
[PB2] in order to jump from an animal and replicate efficiently in
human cells. But Kawaoka and colleagues found that the lysine amino
acid is located in a completely different location on the avian [PB2]
protein in the [pandemic] H1N1 virus. This is what gives the virus
the ability to adapt to and co-opt human cells. The study is
published in the 5 Aug 2010 issue of PLoS Pathogens [see (3) below].
"This pandemic H1N1 [virus] has this mutation and is why it can
replicate so well in humans. This gives us another marker to help
predict the possibility of future flu pandemics," Kawaoka said.

As of 25 Jul 2010, the pandemic virus had caused more than 18 398
deaths worldwide, according to the World Health Organization.

[Byline: Robert Preidt]

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

*****
[2]
Date: Thu 5 Aug 2010
Source: University of Wisconsin-Madison, news release [edited]
<http://www.news.wisc.edu/18278>


H1N1 flu virus used new biochemical trick to cause pandemic
-----------------------------------------------------------
The influenza virus, scientists well know, is a crafty,
shape-shifting organism, constantly changing form to evade host
immune systems and jump from one species, like birds, to another,
mammals. Now, in a report in the current (5 Aug 2010) Public Library
of Science Pathogens [abstract and authors' summary reproduced at (3)
below], an international team of scientists shows that the recent
pandemic- causing H1N1 flu virus used a new biochemical trick to
spread efficiently in humans. The new work expands the repertoire of
known factors flu viruses can use to hijack a host cell and amplify
infection in mammals, including humans. The discovery not only yields
new insight into the subtle biology of flu, but also reveals another
genetic marker public health officials can use to presage pandemics.

"We have found why the pandemic H1N1 virus replicated so well in
humans," says Yoshihiro Kawaoka, one of the world's leading influenza
experts and a professor of pathobiological sciences at the University
of Wisconsin-Madison's School of Veterinary Medicine. The H1N1 flu
virus caused a worldwide epidemic in 2009 and 2010, sickening as many
as 34 million Americans and causing up to an estimated 6000 deaths in
the United States alone. The H1N1 virus, Kawaoka explains, is really
a combination of 4 different avian and swine flu viruses that have
emerged over the past 90 years, and even includes genetic residue of
the 1918 pandemic virus, an influenza that killed as many as 20 million people.

Typically, the presence of 2 amino acids -- lysine and asparagine --
in specific sites on a key avian protein are required for a flu virus
to make the jump from an animal host and replicate efficiently in
human cells. The [pandemic] H1N1 virus lacked both of these amino
acid building blocks, posing a puzzle for scientists. The new study
found that the lysine amino acid resides in a completely different
location on the protein and is responsible for the [pandemic] H1N1
virus's ability to adapt to and co-opt human cells. "This pandemic
H1N1 has this mutation and is why it can replicate so well in
humans," says Kawaoka, who also is a professor at the University of
Tokyo. "This gives us another marker to help predict the possibility
of future flu pandemics."

The new PLoS Pathogens report also includes critical data for the
3-dimensional structure of the H1N1 protein known as PB2, which
originated from an avian virus. The structure was derived from an
exquisite X-ray crystallographic study produced by the Seattle
Structural Genomics Center for Infectious Disease (SSCGID), a
consortium of Washington State-based organizations whose mission is
to provide a "blueprint" for the development of new drugs, vaccines
and diagnostics for deadly infectious diseases.

The structural data, says Kawaoka, provide essential insight into how
the virus interacts with the host cell, and could help provide a
basis for antiviral agents that could be used to thwart a future flu
virus that uses the same amino acid trick to infect human cells.
"Clearly, the host factors in human cells are doing something. The
structure may help us better understand the interplay between the
virus and the host human cell."

According to Bart L. Staker of Emerald BioStructures, Inc., a member
of the SSCGID, the structural data also reveals changes in the
surface shape of the avian virus protein in H1N1, which could, in
turn, be responsible for thwarting factors in the human cell that
would otherwise inhibit infection.

Peter Myler, a principal investigator at Seattle Biomedical Research
Institute (Seattle BioMed) and leader of the SSCGID, said the
structural data plays an essential role in shedding new light on the
H1N1 virus. "By determining the 3-dimensional structure of this
protein, we have new information that can be used to develop
much-needed new interventions for this deadly disease," explains Myler.

[Byline: Terry Devitt]

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

******
[3]
Date: Thu 5 Aug 2010
Source: PLoS Pathog 6(8 ): e1001034. doi:10.1371/journal.ppat.1001034 [edited]
<http://www.plospathogens.org/article/in ... at.1001034>


Ref: Biological and Structural Characterization of a Host-Adapting
Amino Acid in Influenza Virus.
-------------------------------------------------------------------------------------------------
[Authors: Yamada S, Hatta M, Staker BL, Watanabe S, Imai M, et al. (2010)]

Abstract:
---------
Two amino acids (lysine at position 627 or asparagine at position
701) in the polymerase subunit PB2 protein are considered critical
for the adaptation of avian influenza A viruses to mammals. However,
the recently emerged pandemic H1N1 viruses lack these amino acids.
Here, we report that a basic amino acid at position 591 of PB2 can
compensate for the lack of lysine at position 627 and confers
efficient viral replication to pandemic H1N1 viruses in mammals.
Moreover, a basic amino acid at position 591 of PB2 substantially
increased the lethality of an avian H5N1 virus in mice.

We also present the X-ray crystallographic structure of the
C-terminus of a pandemic H1N1 virus PB2 protein. Arginine at position
591 fills the cleft found in H5N1 PB2 proteins in this area,
resulting in differences in surface shape and charge for H1N1 PB2
proteins. These differences may affect the protein's interaction with
viral and/or cellular factors, and hence its ability to support virus
replication in mammals.

Author Summary:
---------------
Influenza viruses that originate from avian species likely have to
acquire adapting amino acid changes to replicate efficiently in
mammals. 2 amino acid changes in the polymerase PB2 protein -- a
glutamic acid to lysine change at position 627 or an aspartic acid to
asparagine change at position 701 -- are known to allow influenza
viruses of avian origin to replicate efficiently in mammals.
Interestingly, the pandemic H1N1 viruses (which possess an avian-like
PB2 gene) do not encode the 'human-type' amino acids PB2-627K and PB2-701N.

Here, we report that a basic amino acid at position 591 of PB2 can
compensate for the lack of PB2-627K and allows efficient replication
of highly pathogenic H5N1 and pandemic H1N1 viruses in mammalian
species. We also present the X-ray crystal structure of the
C-terminal portion of a pandemic H1N1 PB2 protein. The basic amino
acid at position 591 fills a distinctive cleft found in the PB2
proteins of H5N1 viruses. We also speculate on the biological
significance of the altered surface of the H1N1 PB2 protein.

--
Communicated by:
Kunihiko Iizuka

[The authors have discovered that a basic amino acid at position 591
of the PB2 polymerase protein can compensate for the lack of PB2-627K
and allows efficient replication of a highly pathogenic H5N1 virus
and the pandemic H1N1 virus in mammalian species. This is a
significant discovery and time will tell whether other avian
influenza viruses evolve to replicate in mammals by this route. - Mod.CP]

Pandemic (H1N1) 2009 - update 112
Weekly update
06.08.2010 - WHO

As of 1 August 2010, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18449 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and member states and through monitoring of multiple sources of information.

Situation update:

The overall situation remains largely unchanged since the last update. Globally, pandemic influenza transmission remains most active in parts of South Asia and in limited areas of tropical South and Central America. In the temperate zone of the southern hemisphere, overall seasonal and pandemic influenza activity remains low, except in South Africa, where peak wintertime influenza transmission due to circulating seasonal influenza viruses (H3N2 and type B) might have recently occurred. Seasonal influenza viruses, particularly H3N2 viruses, continue to circulate in parts of Central America, East Africa, and Southeast Asia [...]

[...]In sub-Saharan Africa (excluding South Africa), Ghana continued to report sustained transmission of pandemic influenza virus during June and July 2010; during the most recent reporting week, 27% of respiratory samples tested positive for pandemic influenza virus. Limited data indicate that seasonal influenza H3N2 and B viruses continued to circulate at variable levels in parts of eastern Africa and central Africa, respectively. In Cameroon, a sustained period of active transmission of seasonal influenza B viruses, which began during early June 2010, now appears to be subsiding. In Kenya, there has been persistent low level circulation of seasonal H3N2 viruses since late April 2010 ... mehr

Gruß
Birgitt

WHO hebt höchste Warnstufe auf
Schweinegrippe keine Pandemie mehr
10.08.2010 - tagesschau

Die sogenannte Schweinegrippe ist keine Pandemie mehr. Die Weltgesundheitsorganisation (WHO) stufte die Viruserkrankung herab, es handele sich nicht mehr um eine weltumspannende Krankheit, sagte WHO-Chefin Margaret Chan. Das H1N1-Virus habe einen Großteil seines Gefahrenpontenzials eingebüßt ... mehr

Gruß
Birgitt