Published Date: 2011-10-07 16:46:05
Subject: PRO/EDR> Influenza (58): WHO update
Archive Number: 20111007.3019

INFLUENZA (58): WORLD HEALTH ORGANISATION UPDATE
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A ProMED-mail post
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International Society for Infectious Diseases
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Date: Fri 7 Oct 2011
Source: World Health Organisation (WHO), Influenza Update,
Surveillance and Monitoring [edited]
http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/index.html


WHO Update number 144
---------------------
Summary
-------
-- Influenza activity in the temperate regions of the northern
hemisphere remains low or undetectable.
-- Countries in the tropical zone mostly reported low influenza
activity but with some transmission reported in countries of the
Americas (Cuba, Honduras and Bolivia), western Africa (Cameroon), and
southern Asia (India, Thailand, Viet Nam and Singapore).
-- Transmission in South Africa and South America remains low.
-- As reported in the previous update, the number of laboratory
confirmed influenza notifications in Australia is reported to be
declining in Queensland, New South Wales and other states with the
exception of the Northern Territory. Influenza-like illness (ILI)
activity in New Zealand continues around national baseline levels and
the majority of viruses detected have been influenza B.

Countries in the temperate zone of the northern hemisphere
----------------------------------------------------------
The countries in the northern hemisphere temperate zone are in their
inter-seasonal period for influenza. All of the countries in this zone
reported low or no influenza activity.

Countries in the tropical zone
------------------------------
- Southern Asia circulation of influenza viruses (snapshot) pdf,
390kb
http://www.who.int/influenza/surveillance_monitoring/updates/2011_10_07_influenza_southern_asia_circulation_main.pdf

In the tropical countries of the Americas, generally low levels of
influenza transmission are reported; Cuba has experienced an increase
in influenza A(H3N2), while the previously noted circulation of
influenza A(H1N1)pdm09 in the Dominican Republic has decreased to very
low levels. Honduras has had recent circulation of influenza A(H3N2),
which peaked in mid-August. Influenza A(H3N2) circulation in El
Salvador began in mid-August and has been increasing weekly. Most
countries of the tropical area of South America reported low or
undetectable levels of influenza transmission. The previously reported
influenza transmission in Colombia (primarily A(H1N1)pdm09 with lower
numbers of H3N2) and Brazil (roughly equal numbers of A(H1N1)pdm09,
H3N2, with lower numbers of influenza type B) now have returned to
very low levels. However, Bolivia has reported a recent increase in
transmission of influenza A(H1N1)pdm09 after a earlier wave of
influenza A(H3N2) in May-June mainly in La Paz.

In sub-Saharan Africa, some influenza transmission has continued in
the west, notably in Cameroon where transmission has primarily been
influenza B with increasing numbers of influenza A(H1N1)pdm09 in
recent weeks, peaking in week 36. In eastern Africa, continuous
transmission of a mixture of influenza type B, A(H3N2), and
A(H1N1)pdm09 since the peak of transmission in March is reported.

Influenza transmission in tropical Asia has been active in localized
areas. Moderate transmission of primarily influenza A(H3N2) was
recently reported in India, Singapore and Thailand, though
transmission in India has now returned to low levels. Influenza
A(H3N2) circulation in India and Bangladesh was largely replaced by
influenza type B in the recent weeks. Circulation of influenza A(H3N2)
in Thailand, which began 2 to 3 weeks later than the other countries,
has continued at a relatively high level, though it appears to have
recently peaked. Lao People's Democratic Republic has also reported
predominant transmission of influenza A(H3N2) in recent weeks,
increasing markedly in early September. In contrast, Viet Nam and
Cambodia report sustained transmission of predominantly influenza
A(H1N1)pdm09.

Countries in the temperate zone of the southern hemisphere
----------------------------------------------------------
South America
-------------
- Temperate South America circulation of influenza viruses (snapshot)
pdf,388kb
http://www.who.int/influenza/surveillance_monitoring/updates/2011_10_07_influenza_temperate_south_america_circulation_main.pdf

Low levels of influenza activity are now reported in the temperate
regions of South America, where the influenza activity is declining
back to baseline levels. In Chile, influenza A(H1N1)pdm09 detections
were substantially lower than the past 4 weeks, ILI activity and
consultations for respiratory disease in emergency departments also
remained at low levels; 3 deaths from influenza A(H1N1)pdm09 were
reported in week 37, 2 of which had co-morbidities. Transmission is
similar in Argentina, where influenza A(H3N2) has been the most common
virus circulation. The country has reported low and decreasing levels
of ILI and severe acute respiratory illness (SARI) activity and fewer
samples testing positive for influenza into week 38. In Paraguay, the
proportion of SARI hospitalizations, SARI intensive care unit (ICU)
admissions, and SARI related deaths were below 5 percent, all either
similar to or decreased from recent weeks; in the samples tested, no
influenza virus was detected.

In Uruguay the proportions of SARI hospitalizations and SARI deaths
continues to decline below 5 percent; the proportion of SARI ICU
admissions also continued to decrease (5 percent) after peaking in
week 31.

Southern Africa
---------------
- Southern Africa circulation of influenza viruses (snapshot) pdf,
388kb
http://www.who.int/influenza/surveillance_monitoring/updates/2011_10_07_influenza_southern_africa_circulation_main.pdf

Influenza transmission in South Africa has continued at low levels
after 2 peaks in week 23 and week 34. The influenza season was
dominated by influenza A(H1N1)pdm09 with smaller numbers of influenza
type B and some influenza A(H3N2).

Australia, New Zealand and South Pacific
----------------------------------------
- Oceania Melanesia and Polynesia circulation of influenza viruses
(snapshot) pdf, 391kb
http://www.who.int/influenza/surveillance_monitoring/updates/2011_10_07_influenza_oceania_circulation_main.pdf

Influenza transmission rates have remained consistent through week 39
in Australia, although the weekly number of laboratory confirmed
influenza notifications has continued to decline in Queensland, New
South Wales (NSW) and most other states except the Northern Territory.
Overall the peak of influenza notifications seems to have been in
early August, which was above the peak frequency experienced in
previous years except 2009.

The majority of states and territories have reported mostly influenza
A(H1N1)pdm09 with co-circulation of influenza B; except in Tasmania
and NSW where influenza B predominates, and Western Australia
reporting a mix of influenza A(H1N1)pdm09, A(H3N2) and very little
influenza B. From 1 May to 22 Sep 2011, there were 155 influenza
hospitalizations (including 20 ICU admissions) in Victoria, South
Australia, Western Australia and the Australia Capital Territory.
About 53 percent of the hospitalizations and 60 percent of the ICU
admissions were associated with influenza A(H1N1)2009; mean age of the
hospitalized patients was 49 years.

In New Zealand, the rate of national ILI consultations was 30.7 per
100 000. Influenza type A(H3N2) virus and type B account for a large
proportion of influenza viruses detected in New Zealand. In the
Pacific Islands ILI activity has been variable with increased activity
in Fiji, Solomon Islands, Marshall Islands, and Northern Mariana
Islands.

Virological summary
-------------------
During weeks 37 to 38 (11 Sep 2011 to 24 Sep 2011), the number of
laboratory confirmed influenza viruses reported remained low in most
parts of the world. The predominant circulating influenza virus
types/subtypes differed in various countries with the majority of
detections reported as influenza A.

In the southern hemisphere, slight increased influenza activity due to
influenza A(H1N1)pdm09 was reported in Bolivia, while influenza
A(H3N2) virus was predominant in several countries in central and
South America.

Influenza A(H1N1)pdm09, A(H3N2) and B viruses continued to
co-circulate in Australia but in declining levels. Influenza A(H3N2)
and B viruses were predominant in New Zealand but were detected at
lower levels than in recent weeks. In Africa, sporadic detections of
A(H1N1)pdm09, A(H3N2) and B virus were reported in some countries.

In the northern hemisphere influenza activity in general was very
low.

Following the WHO consultation which took place from 26 to 29
September 2011 to review the data generated and collected by the WHO
GISRS together with other available information, it was recommended
that the influenza vaccines for the southern hemisphere 2012 influenza
season contain the following viruses:

-- an A/California/7/2009 (H1N1)pdm09-like virus;
-- an A/Perth/16/2009 (H3N2)-like virus;
-- a B/Brisbane/60/2008-like virus.

Availability of candidate vaccine viruses and instructions to obtain
these viruses can be found on the WHO influenza vaccine viruses web
page.

During weeks 37 to 38 (11 Sep 2011 to 24 Sep 2011), National Influenza
Centres (NICs) from 73 countries, areas or territories reported data
to FluNet. A total of 1299 specimens were reported as positive for
influenza viruses, 960 (73.9 percent) were typed as influenza A and
339 (26.1 percent) as influenza B. Of the sub-typed influenza A
viruses reported, 43.9 percent were influenza A(H1N1)pdm09 and 56.1
percent were influenza A(H3N2).

Influenza virus detection by type/subtype in countries, areas or
territories:
-- Influenza A(H1N1)pdm09: Australia, Bolivia (Plurinational State
of), Brazil, Cambodia, Cameroon, Chile, China, Costa Rica, Cuba,
Dominican Republic, Ecuador, Ghana, Honduras, India, Kenya,
Madagascar, New Zealand, Panama, Singapore, Sri Lanka, Viet Nam
-- Influenza A(H1N1) old seasonal virus: no report
-- Influenza A(H3N2): Argentina, Australia, Bolivia (Plurinational
State of), Brazil, Burkina Faso, Cambodia, Cameroon, Chile, China,
Costa Rica, Cuba, El Salvador, Guatemala, Honduras, India, Kenya, Lao
People's Democratic Republic, Madagascar, New Zealand, Nicaragua,
Republic of Korea, Singapore, South Africa, Spain, Sri Lanka, United
Kingdom of Great Britain and Northern Ireland, United States of
America, Viet Nam
-- Influenza A(H5): no report
-- Influenza B: Australia, Bangladesh, Bolivia (Plurinational State
of), Burkina Faso, Cambodia, Cameroon, Chile, China, Ethiopia, India,
Kenya, New Zealand, Singapore, South Africa, Spain, Sri Lanka, Uganda,
United States of America, Viet Nam
-- No influenza detected: Algeria, Angola, Armenia, Austria,
Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria,
Central African Republic, Denmark, Egypt, Estonia, Finland, France,
Georgia, Germany, Iceland, Iran, Ireland, Jamaica, Japan, Latvia,
Lithuania, Malaysia, Mauritius, Netherlands, Norway, Poland, Republic
of Moldova, Romania, Russian Federation, Rwanda, Slovakia, Slovenia,
Sweden

Maps and Graphs
---------------
Global circulation of influenza viruses (snapshot)
http://www.who.int/influenza/surveillance_monitoring/updates/2011_10_07_influenza_global_circulation.pdf

Northern hemisphere circulation of influenza viruses (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

Update on oseltamivir resistance in influenza A(H1N1)2009 viruses
http://www.who.int/influenza/surveillance_monitoring/updates/2011_10_07_weekly_web_update_oseltamivir_resistance.pd

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

[In brief: Influenza activity in the temperate regions of the northern
hemisphere remains low or undetectable. Countries in the tropical zone
mostly reported low influenza activity but with some transmission
reported. The numbers of laboratory confirmed influenza notifications
in Australia and New Zealand are in decline. No new strains not
covered by the current vaccine have appeared.

Readers can obtain a rapid appreciation of the current global
situation by accessing the relevant WHO Influenza Maps. - Mod.CP]

See Also