Giuseppe
Emeritus
[Source: World Health Organization, full PDF document: (LINK). Edited.]
Influenza Update N? 197, 24 October 2013
Summary
Countries in the temperate zone of the northern hemisphere
North America
Overall influenza activity in North America remained at low levels throughout the region. In Canada and the United States of America, influenza activity remained at interseasonal levels. In Mexico influenza activity remained low after a period of two months (July ? August) with higher influenza activity, while reports of ARI and pneumonia increased slightly in comparison to previous weeks.
Europe
Influenza activity in Europe remained at low levels in all countries that reported data. Between the 7 and 13 October only 0.5% (19/3931) of the specimens tested were positive for influenza virus. However, many countries started reporting increased consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI).
Northern Africa and the Western and Central Asia region
Influenza activity was low in the Northern Africa and western and central Asia regions. Only Qatar reported influenza activity, mainly influenza A virus (not subtyped), since the end of August. In Bahrain and Georgia, ILI activity increased since early September, but no influenza detections were reported.
Northern Asia
Influenza activity in the temperate region of Asia remained at interseasonal levels since late May. In Mongolia, clinical respiratory illness activity began to increase since mid-August, but no influenza viruses were detected in this period.
(...)
Countries in the tropical zone
Tropical countries of the Americas/Central America and the Caribbean
Overall influenza activity in the Caribbbean and Central America was at low levels throughout the regions. Decreasing numbers of influenza A virus have been detected, but influenza transmission had largely come to an end in the last few weeks in these countries; except in Honduras where ILI and SARI indicators increased in the last 5 weeks, associated with influenza A(H1N1)pdm09 and RSV detection. In the rest of the countries, co-circulation of influenza A(H3N2) and influenza B viruses were reported, and RSV predominated among respiratory viruses in Costa Rica, Cuba, El Salvador, Guatemala and Panama.
(...)
In tropical South America, respiratory virus activity continued decreasing following a period of high influenza activity in July and August.
In Colombia, the proportions of outpatient visits, hospitalizations, and ICU admissions were similar to reports for the same period in previous years.
In Venezuela, ARI and pneumonia levels were reported within the expected values for the time of year.
In Ecuador the number of positive influenza samples steadily decreased since its influenza peak in August, and among positive specimens influenza A (H1N1)pdm09 predominated.
In Peru, reports of ARI in children under five years of age followed a decreasing trend.
In the Plurinational State of Bolivia the proportion of SARI-related hospitalizations were reported as elevated compared to the data from the same period last year, especially in the eastern part of the country (Santa Cruz), where detection of influenza A(H1N1)pdm09 continued in high levels since the end of July.
Brazil showed a continuing decline in the number of positive influenza samples since July, and among recent positive specimens influenza A untyped and influenza B viruses were detected.
Central African tropical region
Cote d?Ivoire, Ghana and Kenya reported influenza virus detections. In Cote d?Ivoire influenza B was the predominant virus detected, while Ghana reported only influenza A(H3N2). Kenya reported low influenza activity comprised of both influenza A(H1N1)pdm09 and influenza B viruses.
(...)
Tropical Asia
Influenza transmission in southern Asia was low in most countries. Both influenza A(H1N1)pdm09 and A(H3N2) viruses were reported in this area.
A decrease in the influenza associated hospital rates and ILI consultation rates was seen since early October in Hong Kong Special Administrative Region (SAR), China. The influenza transmission in Hong Kong SAR was predominated by influenza A(H3N2) virus.
In the south of China, influenza activity increased slightly since early September. Influenza A(H3N2) virus was the main virus reported, but influenza A(H1N1)pdm09 and influenza B viruses were also detected.
(...)
Overall, influenza transmission in South East Asia remained at a low level. Influenza transmission and ILI activity decreased in Thailand since early September. In Viet Nam, an increase was seen in the number of influenza positive ILI samples since mid-September, mainly due to increased influenza B and influenza A(H3N2) virus transmission.
Countries in the temperate zone of the southern hemisphere
Temperate countries of South America
In the temperate countries of South America, ARI activity was reported at expected levels for the time of year with the exception of high ILI activity in Paraguay. RSV continued to be the most common respiratory virus detected in Argentina and Chile, although it continued its decreasing trend.
In Argentina, ILI activity continued its decreasing trend since its peak in June and July of this year.
In Chile the proportion of SARI-associated hospitalizations continued to decrease and ILI activity remained low.
In Paraguay, the ILI consultation rate was higher than expected for the time of year, but influenza virus detection decreased.
In Uruguay the proportion of SARI-associated hospitalizations decreased from levels reported in the previous two weeks.
(...)
Temperate countries of Southern Africa
After a peak in influenza activity in South Africa due to influenza A(H1N1)pmd09 in June, a small second peak continued to be observed in the last few weeks due to increased influenza A(H3N2) and influenza B circulation.
Oceania, Melanesia and Polynesia
Overall, in Australia, New Zealand and the Pacific Islands influenza activity decreased.
In Australia, during the period from 14 September to 27 September 2013, the distribution of influenza types and subtypes was variable across jurisdictions. In Western Australia, influenza A(H3N2) remained the predominant virus subtype, however the proportion of A(H1N1)pdm09 increased. Whilst the proportion of influenza B virus nationally remained relatively stable, there were increasing proportions of influenza B in New South Wales, South Australia and Queensland; combined with decreases in Victoria. Influenza positivity levels ranged from 16% (330/2032) in the national sentinel laboratory surveillance to 29.5% (62/210) in the Australian Sentinel Practices Research Network (ASPREN). The Influenza Complications Alert Network (FluCAN) sentinel hospital surveillance system reported that the rate of influenza associated hospitalisations started to decline since mid-September. During the season, around 12% of influenza associated hospitalisations were admitted directly to ICU. The age distribution of hospital admissions showed peaks in the 0-9 and over 60 years age groups.
In New Zealand, ILI activity reached almost the baseline threshold in early September, but decreased since then. Out of 291 samples received in the last week 112 were positive for influenza (39%): 48 were influenza B, 21 were influenza A(H3N2), 12 were influenza A(H1N1)pdm09 and 31 influenza A (not subtyped). In Auckland and Counties Manukau District Health Boards, decreased influenza activity was reported in community surveillance and hospital surveillance.
(...)
Source of data
The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two 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.
Link to web pages
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Influenza Update N? 197, 24 October 2013
Summary
- Although in many European countries influenza-like illness activity started to increase, influenza detections in the northern hemisphere temperate zones remained low.
- In the regions of tropical Asia influenza activity was variable from country to country. In Hong Kong Special Administrative Region,China, influenza detections decreased, while in the south of China an increase in influenza detections was seen. In South East Asia, influenza dections decreased in Thailand, but increased in Viet Nam. In this area, co-circulation of influenza A(H3N2) and influenza B virus was reported.
- In the Caribbean region of Central America and tropical South America countries, reported cases of influenza A infection remained at low levels among most Caribbean islands and Central American countries. Respiratory syncytial virus (RSV) continued to predominate, but the RSV activity largely remained within expected seasonal levels.
- Influenza activity peaked in the temperate countries of South America and in South Africa in late June. Temperate South American countries reported co-circulation of influenza B and A (H3N2) in most countries, and while RSV activity continued to predominate, it showed an overall decreasing trend.
- In Australia and New Zealand, numbers of influenza viruses detected and rates of influenza-like illness decreased. Co-circulation of influenza A(H1N1)pdm09, A(H3N2) and B viruses was reported in both countries.
- Additional and updated information on non-seasonal influenza viruses can be found at: http://who.int/influenza/human_animal_interface/HAI_Risk_Assessment/en/index.html
Countries in the temperate zone of the northern hemisphere
North America
Overall influenza activity in North America remained at low levels throughout the region. In Canada and the United States of America, influenza activity remained at interseasonal levels. In Mexico influenza activity remained low after a period of two months (July ? August) with higher influenza activity, while reports of ARI and pneumonia increased slightly in comparison to previous weeks.
Europe
Influenza activity in Europe remained at low levels in all countries that reported data. Between the 7 and 13 October only 0.5% (19/3931) of the specimens tested were positive for influenza virus. However, many countries started reporting increased consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI).
Northern Africa and the Western and Central Asia region
Influenza activity was low in the Northern Africa and western and central Asia regions. Only Qatar reported influenza activity, mainly influenza A virus (not subtyped), since the end of August. In Bahrain and Georgia, ILI activity increased since early September, but no influenza detections were reported.
Northern Asia
Influenza activity in the temperate region of Asia remained at interseasonal levels since late May. In Mongolia, clinical respiratory illness activity began to increase since mid-August, but no influenza viruses were detected in this period.
(...)
Countries in the tropical zone
Tropical countries of the Americas/Central America and the Caribbean
Overall influenza activity in the Caribbbean and Central America was at low levels throughout the regions. Decreasing numbers of influenza A virus have been detected, but influenza transmission had largely come to an end in the last few weeks in these countries; except in Honduras where ILI and SARI indicators increased in the last 5 weeks, associated with influenza A(H1N1)pdm09 and RSV detection. In the rest of the countries, co-circulation of influenza A(H3N2) and influenza B viruses were reported, and RSV predominated among respiratory viruses in Costa Rica, Cuba, El Salvador, Guatemala and Panama.
(...)
In tropical South America, respiratory virus activity continued decreasing following a period of high influenza activity in July and August.
In Colombia, the proportions of outpatient visits, hospitalizations, and ICU admissions were similar to reports for the same period in previous years.
In Venezuela, ARI and pneumonia levels were reported within the expected values for the time of year.
In Ecuador the number of positive influenza samples steadily decreased since its influenza peak in August, and among positive specimens influenza A (H1N1)pdm09 predominated.
In Peru, reports of ARI in children under five years of age followed a decreasing trend.
In the Plurinational State of Bolivia the proportion of SARI-related hospitalizations were reported as elevated compared to the data from the same period last year, especially in the eastern part of the country (Santa Cruz), where detection of influenza A(H1N1)pdm09 continued in high levels since the end of July.
Brazil showed a continuing decline in the number of positive influenza samples since July, and among recent positive specimens influenza A untyped and influenza B viruses were detected.
Central African tropical region
Cote d?Ivoire, Ghana and Kenya reported influenza virus detections. In Cote d?Ivoire influenza B was the predominant virus detected, while Ghana reported only influenza A(H3N2). Kenya reported low influenza activity comprised of both influenza A(H1N1)pdm09 and influenza B viruses.
(...)
Tropical Asia
Influenza transmission in southern Asia was low in most countries. Both influenza A(H1N1)pdm09 and A(H3N2) viruses were reported in this area.
A decrease in the influenza associated hospital rates and ILI consultation rates was seen since early October in Hong Kong Special Administrative Region (SAR), China. The influenza transmission in Hong Kong SAR was predominated by influenza A(H3N2) virus.
In the south of China, influenza activity increased slightly since early September. Influenza A(H3N2) virus was the main virus reported, but influenza A(H1N1)pdm09 and influenza B viruses were also detected.
(...)
Overall, influenza transmission in South East Asia remained at a low level. Influenza transmission and ILI activity decreased in Thailand since early September. In Viet Nam, an increase was seen in the number of influenza positive ILI samples since mid-September, mainly due to increased influenza B and influenza A(H3N2) virus transmission.
Countries in the temperate zone of the southern hemisphere
Temperate countries of South America
In the temperate countries of South America, ARI activity was reported at expected levels for the time of year with the exception of high ILI activity in Paraguay. RSV continued to be the most common respiratory virus detected in Argentina and Chile, although it continued its decreasing trend.
In Argentina, ILI activity continued its decreasing trend since its peak in June and July of this year.
In Chile the proportion of SARI-associated hospitalizations continued to decrease and ILI activity remained low.
In Paraguay, the ILI consultation rate was higher than expected for the time of year, but influenza virus detection decreased.
In Uruguay the proportion of SARI-associated hospitalizations decreased from levels reported in the previous two weeks.
(...)
Temperate countries of Southern Africa
After a peak in influenza activity in South Africa due to influenza A(H1N1)pmd09 in June, a small second peak continued to be observed in the last few weeks due to increased influenza A(H3N2) and influenza B circulation.
Oceania, Melanesia and Polynesia
Overall, in Australia, New Zealand and the Pacific Islands influenza activity decreased.
In Australia, during the period from 14 September to 27 September 2013, the distribution of influenza types and subtypes was variable across jurisdictions. In Western Australia, influenza A(H3N2) remained the predominant virus subtype, however the proportion of A(H1N1)pdm09 increased. Whilst the proportion of influenza B virus nationally remained relatively stable, there were increasing proportions of influenza B in New South Wales, South Australia and Queensland; combined with decreases in Victoria. Influenza positivity levels ranged from 16% (330/2032) in the national sentinel laboratory surveillance to 29.5% (62/210) in the Australian Sentinel Practices Research Network (ASPREN). The Influenza Complications Alert Network (FluCAN) sentinel hospital surveillance system reported that the rate of influenza associated hospitalisations started to decline since mid-September. During the season, around 12% of influenza associated hospitalisations were admitted directly to ICU. The age distribution of hospital admissions showed peaks in the 0-9 and over 60 years age groups.
In New Zealand, ILI activity reached almost the baseline threshold in early September, but decreased since then. Out of 291 samples received in the last week 112 were positive for influenza (39%): 48 were influenza B, 21 were influenza A(H3N2), 12 were influenza A(H1N1)pdm09 and 31 influenza A (not subtyped). In Auckland and Counties Manukau District Health Boards, decreased influenza activity was reported in community surveillance and hospital surveillance.
(...)
Source of data
The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two 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.
Link to web pages
- Epidemiological Influenza updates: http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance
- Epidemiological Influenza updates archives 2012: http://www.who.int/influenza/surveillance_monitoring/updates/GIP_surveillance_2012_archives
- Virological surveillance updates : http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport
- Virological surveillance updates archives : http://www.who.int/influenza/gisrs_laboratory/updates/en/index.html
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