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Published Date: 2010-08-07 15:00:08
Subject: PRO/AH/EDR> Influenza pandemic (H1N1) (63): WHO update 112
Archive Number: 20100807.2680

INFLUENZA PANDEMIC (H1N1) (63): WORLD HEALTH ORGANISATION UPDATE 112
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International Society for Infectious Diseases
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Date: Fri 6 Aug 2010
Source: World Health Organisation (WHO), GAR, Disease Outbreak News
[abbrev., edited]
<http://www.who.int/csr/don/2010_08_06/en/index.html>

Pandemic (H1N1) 2009 - Update 112
---------------------------------
Weekly update
-------------
As of 1 Aug 2010, worldwide more than 214 countries and overseas
territories or communities have reported laboratory confirmed cases
of pandemic influenza H1N1 2009, including over 18 449 deaths. The
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.

During the 2010 winter of the temperate southern hemisphere, the most
active areas of influenza virus transmission have been in South
Africa, where the majority of influenza virus detections have been
seasonal influenza H3N2 and type B viruses; pandemic influenza virus
has been detected there only sporadically. Elsewhere in Argentina,
Chile, New Zealand, and Australia, overall influenza activity remains
low and below levels observed during recent, mild, pre-pandemic
influenza seasons; among the latter 3 countries, pandemic influenza
viruses have been detected most frequently; however, low level
co-circulation of seasonal influenza H3N2 and type B has also been observed.

In South Africa, the current wintertime epidemic of seasonal
influenza appears to have peaked during early July 2010 and
stabilized since then; to date, influenza type B viruses have
accounted for a greater proportion of influenza viruses detected
among severe (SARI) cases than have influenza H3N2 viruses. Chile and
Argentina continue to observe low levels of respiratory diseases in
the population, and much of what has been observed in recent months
has been due to circulation of respiratory viruses other than
influenza, particularly RSV.

In Australia and New Zealand there has been a sustained upward trend
in the rates of ILI over the past 6-8 weeks, particularly in recent
weeks, however, overall rates remain well below those observed during
the same period in 2009 during the 1st pandemic wave in the southern
hemisphere. Data on the clinical and epidemiological pattern of
pandemic influenza virus infection during the current winter season
have been limited due to the fact that there has been limited virus
transmission to date; however, preliminary data suggests that the
pattern has not changed compared to what was seen last winter during
the 1st pandemic wave in the southern hemisphere.

In Asia, the most active areas of pandemic influenza virus
transmission currently are in parts of India, and to a much lesser
extent, in parts of Nepal and Bhutan. Transmission appears to have
peaked in the southern state of Kerala, while transmission remains
moderately intense in the western state of Maharashtra, and may be
increasing in several eastern states, including Orissa and West
Bengal. Limited, preliminary data suggests that the overall intensity
and severity of the current regional epidemics in India do not yet
appear to exceed what was observed during the 1st wave in 2009;
however, it is too early make a complete assessment of the situation
as the regional epidemics are still evolving. Similarly, there has
been no evidence to date to suggest that clinical and epidemiological
pattern of pandemic influenza virus infection has changed during the
current period of active transmission.

Overall, across India, approximately one quarter of respiratory
samples tested positive for influenza as of 3rd week of July 2010;
however, in at least one region of India, up to one 3rd of
respiratory samples tested positive for influenza. In addition to the
recent increases in circulation of pandemic influenza viruses in
India, there has been, in recent months, active circulation of
seasonal influenza type B viruses, and to a lesser extent, seasonal
influenza H3N2 viruses. In neighboring Bangladesh, Bhutan, and Nepal,
but not Sri Lanka, there is limited evidence of low levels of
pandemic influenza virus transmission, including reports of localized
outbreaks in Nepal and Bhutan. In Southeast Asia, low to sporadic
levels of co-circulating pandemic and seasonal influenza viruses have
been detected across the region over the past month.

In the tropical regions of the Americas, active subregional
co-circulation of seasonal and pandemic influenza viruses continued
to be detected during July 2010. Since early June 2010, predominantly
seasonal influenza H3N2 viruses have circulated in Panama, Nicaragua,
and Honduras; seasonal influenza B and more recently H3N2 viruses in
El Salvador; and, predominantly pandemic influenza and H3N2 viruses
in Costa Rica and Columbia.

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 percent 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.

In the temperate regions of the Northern hemisphere, pandemic and
seasonal influenza viruses have been detected only sporadically or at
very low levels during the past month. (Countries in temperate
regions are defined as those north of the Tropic of Cancer or south
of the Tropic of Capricorn, while countries in tropical regions are
defined as those between these 2 latitudes.)

Weekly update (Virological surveillance data)
<http://www.who.int/csr/disease/swineflu/laboratory06_08_2010/en/index.html>.

Weekly update on oseltamivir resistance to pandemic influenza A
(H1N1) 2009 viruses [pdf 17kb]
<http://www.who.int/csr/disease/swineflu/oseltamivirresistant20100806.pdf>.

Map of influenza activity and virus subtypes (Week 29: 18 Jul - 24 Jul 2010)

Map of influenza activity and virus subtypes [jpg 834kb]
<http://www.who.int/csr/disease/swineflu/don2010_08_06.jpg>

The displayed data reflect the most recent data reported to Flunet
(<http://gamapserver.who.int/GlobalAtlas/home.asp>), WHO regional
offices or on Ministry of health websites in the last 2 weeks. The
percent of specimens tested positive for influenza includes all
specimens tested positive for seasonal or pandemic influenza. The pie
charts show the distribution of virus subtypes among all specimens
that were tested positive for influenza. The available country data
were joined in larger geographical areas with similar influenza
transmission patterns to be able to give an overview
(<http://www.who.int/csr/disease/swineflu/transmission_zones/en>).

Qualitative indicators (Week 29, 2009 to Week 29, 2010: 13 July 2009
- 24 July 2010)
The maps referenced below display information on the qualitative
indicators reported. Information is available for approximately 60
countries each week. Implementation of this monitoring system is
ongoing and completeness of reporting is expected to increase over time.

Geographic spread of influenza activity - Map timeline
<http://gamapserver.who.int/h1n1/qualitative_indicators/atlas.html?indicator=i0&date=Week%2029%20%2819-Jul-2010%20:%2025-Jul-2010%29>
Trend of respiratory diseases activity compared to the previous week
- Map timeline
<http://gamapserver.who.int/h1n1/qualitative_indicators/atlas.html?indicator=i1&date=Week%2029%20%2819-Jul-2010%20:%2025-Jul-2010%29>
Intensity of acute respiratory diseases in the population - Map timeline
<http://gamapserver.who.int/h1n1/qualitative_indicators/atlas.html?indicator=i2&date=Week%2029%20%2819-Jul-2010%20:%2025-Jul-2010%29>
Impact on health care services - Map timeline
<http://gamapserver.who.int/h1n1/qualitative_indicators/atlas.html?indicator=i3&date=Week%2029%20%2819-Jul-2010%20:%2025-Jul-2010%29>
Laboratory-confirmed cases of pandemic (H1N1) 2009 as officially
reported to WHO by States Parties to the IHR (2005) as of 1 Aug 2010
Map of affected countries and deaths
<http://gamapserver.who.int/h1n1/cases-deaths/h1n1_casesdeaths.html>.

The countries and overseas territories/communities that have newly
reported their 1st pandemic (H1N1) 2009 confirmed cases since the
last web update (No. 111): none.
The countries and overseas territories/communities that have newly
reported their 1st deaths among pandemic (H1N1) 2009 confirmed cases
since the last web update (No. 111): none.

Region / Deaths*
----------------
WHO Regional Office for Africa (AFRO) / 168**
WHO Regional Office for the Americas (AMRO) / At least 8533
WHO Regional Office for the Eastern Mediterranean (EMRO) / 1019**
WHO Regional Office for Europe (EURO) / At least 4879**
WHO Regional Office for South-East Asia (SEARO) / 1992
WHO Regional Office for the Western Pacific (WPRO) / 1858
Total* / At least 18 449
*The reported number of fatal cases is an under-representation of the
actual numbers as many deaths are never tested or recognized as
influenza-related.
**Unchanged since update 111.

--
Communicated by:
ProMED-mail Rapporteur Marianne Hopp

[In brief: During the 2010 winter of the temperate southern
hemisphere, the most active areas of influenza virus transmission
have been in South Africa, where the majority of influenza virus
detections have been seasonal influenza H3N2 and type B viruses;
pandemic influenza virus has been detected there only sporadically.
In the temperate regions of the Northern hemisphere, pandemic and
seasonal influenza viruses have been detected only sporadically or at
very low levels during the past month. - Mod.CP]

See Also