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World Flu Update

Sunday, January 8, 2012 // Uncategorized

Here’s the information from the World Health Organization on flu activity so far this year.  This is from Pro Med Digest and on line reporting service that sends daily (sometimes multiple times a day) reports on plant, animal and human disease activity around the world.  As a reminder, this is the compsosition of this year’s flu vaccine from the CDC’s website:

The Food and Drug Administration (FDA) recommended that the United State’s 2011-2012 seasonal influenza vaccine contain the following three vaccine viruses:

  • an A/California/7/2009 (H1N1)-like virus;
  • an A/Perth/16/2009 (H3N2)-like virus; and
  • a B/Brisbane/60/2008-like virus.

WHO Influenza Update number 150
– ——————————
Summary
– ————
– – Influenza activity in the temperate regions of the northern
hemisphere remains below seasonal threshold levels, though notable
increases in activity have been reported in some areas of Canada,
Europe (Spain and Turkey), northern Africa (Tunisia and Algeria), and
the Middle East (Iran). The persistence of the increased activity over
the last few weeks in these areas likely represents the start of the
influenza transmission season.

– – The viruses detected throughout the northern hemisphere temperate
zone have been predominantly of the A(H3N2) subtype. Only very small
numbers of influenza A(H1N1)pdm09 have been reported in recent weeks.

– – Countries in the tropical zone reported low levels of influenza
activity except for Costa Rica, which is primarily detecting influenza
A(H3N2).

– – Influenza activity in the temperate countries of the southern
hemisphere is at inter-seasonal levels, though Chile and Australia
both report persistent transmission of A(H3N2) with smaller numbers of
influenza type B in Australia.

Countries in the temperate zone of the northern hemisphere
– ————————————-
Influenza activity in the northern hemisphere temperate regions is
still below baseline, though increased respiratory disease activity
and influenza virus detections have been noted in some areas.

North America
– – North America circulation of influenza viruses (late March – end
December 2011 snapshot)
<http://www.who.int/influenza/surveillance_monitoring/updates/2012_01_06_influenza_north_america_circulation_main.jpg>

In Canada, the percent of positive influenza tests and consultation
rates for influenza-like illness (ILI) have persistently increased
since mid-December 2011. However, nationally, influenza activity
remained at inter-seasonal levels. Localized influenza activity was
reported in the region of British Columbia, and sporadic cases were
reported in 9 regions of 4 provinces (Alberta, British Columbia,
Ontario and Quebec). Three influenza outbreaks in long term care
facilities and 2 paediatric influenza hospitalisations were reported
in the last week. Of the 63 laboratory confirmed cases reported, 51
were influenza A(H3N2), 7 were unsubtyped influenza A, and 2 were
influenza type B. To date, this season [2011-2012], there have been 10
adult influenza hospitalisations, of which 6 were over 65 years of
age.

In the United States of America, nationally, ILI consultations were
low (1.2 percent) and remained below the baseline level (2.4 percent),
and the percentage of samples positive for influenza remained below 2
percent; both have increased since mid-December 2011. Of the nearly
1000 virus detections reported since October 2011, 85 percent have
been influenza type A. Of the influenza A viruses that have been
subtyped, 84 percent were A(H3N2) and the remainder A(H1N1)pdm09. The
proportion of deaths due to pneumonia and influenza reported in the
122 cities sentinel surveillance system was low compared to previous
years.

Europe
– – Western Europe circulation of influenza viruses (late March – end
December 2011 snapshot)
<http://www.who.int/influenza/surveillance_monitoring/updates/2012_01_06_influenza_western_europe_circulation_main.jpg>

In Europe, influenza activity remains low, though respiratory disease
activity and influenza virus detections have started to increase in
some areas over a period of several weeks. ILI consultations and
admissions for severe acute respiratory infections (SARI) remain at
inter-seasonal levels overall. Of the 35 countries reporting on the
geographical distribution of influenza activity, 21 reported no
activity, one reported local activity (Italy), and 13 reported
sporadic activity in recent weeks. Spain and Turkey reported notable
increases in influenza virus detections among sentinel samples with
percentages of positive samples of 17 percent and 23 percent,
respectively. Influenza A(H3N2) was the most common virus detected. In
France, the consultation rate for acute respiratory infections
exceeded the seasonal baseline level; however, there was no
corresponding increase in ILI consultations or influenza virus
detections. 23 percent of European sentinel samples tested for
influenza in epidemiological week 51 were positive, a doubling from
the previous week. Influenza A(H3N2) was the most common virus
identified; 94 percent of 414 influenza A viruses characterized were
the A(H3N2) subtype.

Northern Africa and Eastern Mediterranean
The northern Africa and eastern Mediterranean regions have been
reporting increasing numbers of positive influenza specimens since
October 2011, particularly in Algeria, Tunisia and Iran. As in Europe,
influenza A(H3N2) was the predominant subtype detected.

Temperate countries of Asia
In northern China, influenza activity increased slightly, to 8.6
percent, since the previous week; influenza B virus is still the
predominant strain in China. Republic of Korea and Japan have both
reported small but slightly increased numbers of influenza positive
specimens in recent weeks, most of which were A(H3N2).

Countries in the tropical zone
– ————————-
Tropical countries of the Americas
No notable influenza transmission has been reported in the majority of
Caribbean and central American countries, with the exception of Costa
Rica, which has continued to report increasing numbers of influenza
A(H3N2) detections.

Sub-Saharan Africa
In sub-Saharan Africa, only sporadic detections or low level
transmission were reported. Transmission of influenza A(H3N2) in
Cameroon appears to be decreasing after peaking in mid-December 2011.
Kenya has reported continuous influenza transmission; however, the
number of positive specimens has been decreasing in the past 4 weeks
and is now at a very low level.

Tropical Asia
Overall, the influenza activity in tropical Asia remained low. Since
September 2011, India has continued to report low level influenza B
circulation. Following peaks in influenza activity in September 2011,
Lao People’s Democratic Republic, Cambodia and Viet Nam have reported
decreasing transmission, which has now returned to low levels. Other
countries in tropical Asia continue to report small numbers of both
A(H3N2) and influenza type B.

Countries in the temperate zone of the southern hemisphere
– ——————————-
– – Chile circulation of influenza viruses (snapshot) pdf, 390kb
<http://www.who.int/influenza/surveillance_monitoring/updates/2012_01_06_influenza_chile_circulation_main.pdf>

– – Australia circulation of influenza viruses (snapshot) pdf, 395kb
<http://www.who.int/influenza/surveillance_monitoring/updates/2012_01_06_influenza_australia_circulation_main.pdf>

In temperate countries of the southern hemisphere, influenza activity
is at inter-seasonal levels; however, Chile and Australia both report
low levels of persistent influenza A(H3N2), with much smaller numbers
of influenza type B also reported in Australia.

Source of data
– ————
The Global Influenza Programme monitors influenza activity worldwide
and publishes an update every 2 weeks. The updates are based on
available epidemiological and virological data sources, including
FluNet (reported by the Global Influenza Surveillance and Response
System) and influenza reports from WHO Regional Offices and Member
States. Completeness can vary among updates due to availability and
quality of data available at the time when the update is developed.

Maps
– ——-
Global circulation of influenza viruses (snapshot)
<http://www.who.int/influenza/surveillance_monitoring/updates/2012_01_06_influenza_global_circulation.pdf>

Northern hemisphere circulation of influenza virises (real time)
<http://gamapserver.who.int/gareports/Default.aspx?ReportNo=5&Hemisphere=Northern>

Southern hemisphere circulation of influenza viruses (real time)
<http://gamapserver.who.int/gareports/Default.aspx?ReportNo=5&Hemisphere=Southern>

Global Health Observatory — Map Gallery
<http://gamapserver.who.int/mapLibrary/app/searchResults.aspx>

– —
Communicated by:
ProMED-mail Rapporteur Marianne Hopp
In summary:  The flu activity has been low thus far this year and the strains reported are covered by the vaccine.  This is good news.

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