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WHO, Influenza Update N? 196, 14 October 2013: S. China, higher flu interseason viral detection than prev. year
[Source: World Health Organization, full PDF document: (LINK). Edited.]
Influenza Update N? 196, 14 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.
Europe
Influenza activity in Europe remained at interseasonal levels. None of the specimens collected from sentinel sites between the 10th and 22nd of September tested positive for influenza. However, many countries started reporting increased consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI).
Northern Africa and the Western Asia region
Influenza activity was low in the Northern Africa and western Asia regions. Only Qatar reported influenza activity, mainly influenza A virus (not subtyped), since the end of August.
Northern Asia
Influenza activity in the temperate region of Asia remained at interseasonal levels since late May. In Mongolia, clinical activity started 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 a low level throughout the region. Decreasing numbers of influenza A virus have been seen throughout the region, but influenza transmission had largely come to an end in the last few weeks in these countries. Co-circulation of influenza A(H3N2) and influenza B virues were reported, and RSV predominated among respiratory viruses in Costa Rica , El Salvador Nicaragua 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.
In Peru, reports of ARI in children under five years of age have been increasing since July, but were consistent with levels from previous years.
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, and laboratory data from CENETROP in Santa Cruz showed that of 182 SARI samples analyzed in the beginning of October, 33% were positive for a respiratory virus(a 9% increase from the previous week).
Brazil showed a continuing decline in the number of positive influenza samples since July, and among recent positive samples influenza A untyped and influenza B viruses were detected.
(...)
Central African tropical region
Cote d?Ivoire, Ghana and Kenya reported circulating influenza viruses.
In Cote d?Ivoire and Ghana, influenza B and A(H3N2) were the predominant viruses detected. Kenya reported low influenza activity due to both influenza A(H3N2) and influenza B viruses.
(...)
Tropical Asia
Influenza transmission in southern and South East Asia was low in most countries. Both influenza A(H1N1)pdm09 and A(H3N2) viruses were reported in this area.
Since early July, an increase in influenza transmission was seen in Hong Kong Special Administrative Region (SAR), China. The influenza transmission in Hong Kong SAR was predominated by influenza A(H3N2) virus. This increased transmission was also seen in the influenza associated hospital rates in this region; mainly the rates among 0-4 year old patients increased over the past month.
In the south of China, influenza activity remained at an interseasonal level. However, the number of influenza virus detections has been higher in this year?s interseasonal period compared to the previous year.
(...)
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 and RSV continued to be the most common respiratory virus detected in Argentina and Chile although cases had largely decreased.
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.
In Paraguay, the ILI consultation rate was higher than expected for the time of year, but with decreased influenza and respiratory virus detection.
In Uruguay the proportion of SARI-associated hospitalizations increased from levels reported in the previous week, but proportions of ICU admissions continued to decline.
(...)
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 was 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 seemed to have peaked.
In Australia, during the period from 30 August to 13 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. Influenza type B continued to represent over half of Victoria's influenza notifications. In recent weeks there have been increasing proportions of influenza B virus in Queensland and South Australia.
Influenza positivity levels ranged from 15% (309/2114) in the national sentinel laboratory surveillance to 28.1% (56/199) 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 had been relatively stable since mid-August. Almost 15% 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 was almost at the baseline threshold in early September, but decreased since then. Out of 303 samples received in the last week 161 were positive for influenza (53%): 49 were influenza B, 16 were influenza A(H3N2), 22 were influenza A(H1N1)pdm09 and 74 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
Contact fluupdate@who.int
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Influenza Update N? 196, 14 October 2013
Summary
- Although in many European countries influenza-like illness activity started to increase, influenza activity in the northern hemisphere temperate zones remained at inter-seasonal levels
- In most regions of tropical Asia influenza activity was at a low level, with the exception of Hong Kong Special Administrative Region,China, where influenza transmission increased due to influenza A(H3N2).
- In the Caribbean region of Central America and tropical South America countries, cases of influenza decreased. While acute respiratory illness remained stable in the Caribbean and Central America. Respiratory syncytial virus (RSV) predominated but the RSV activity 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 acute respiratory disease activity within expected seasonal levels, and RSV activity largely declined.
- In Australia and New Zealand, numbers of influenza viruses detected and rates of influenza-like illness seemed to have peaked. 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.
Europe
Influenza activity in Europe remained at interseasonal levels. None of the specimens collected from sentinel sites between the 10th and 22nd of September tested positive for influenza. However, many countries started reporting increased consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI).
Northern Africa and the Western Asia region
Influenza activity was low in the Northern Africa and western Asia regions. Only Qatar reported influenza activity, mainly influenza A virus (not subtyped), since the end of August.
Northern Asia
Influenza activity in the temperate region of Asia remained at interseasonal levels since late May. In Mongolia, clinical activity started 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 a low level throughout the region. Decreasing numbers of influenza A virus have been seen throughout the region, but influenza transmission had largely come to an end in the last few weeks in these countries. Co-circulation of influenza A(H3N2) and influenza B virues were reported, and RSV predominated among respiratory viruses in Costa Rica , El Salvador Nicaragua 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.
In Peru, reports of ARI in children under five years of age have been increasing since July, but were consistent with levels from previous years.
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, and laboratory data from CENETROP in Santa Cruz showed that of 182 SARI samples analyzed in the beginning of October, 33% were positive for a respiratory virus(a 9% increase from the previous week).
Brazil showed a continuing decline in the number of positive influenza samples since July, and among recent positive samples influenza A untyped and influenza B viruses were detected.
(...)
Central African tropical region
Cote d?Ivoire, Ghana and Kenya reported circulating influenza viruses.
In Cote d?Ivoire and Ghana, influenza B and A(H3N2) were the predominant viruses detected. Kenya reported low influenza activity due to both influenza A(H3N2) and influenza B viruses.
(...)
Tropical Asia
Influenza transmission in southern and South East Asia was low in most countries. Both influenza A(H1N1)pdm09 and A(H3N2) viruses were reported in this area.
Since early July, an increase in influenza transmission was seen in Hong Kong Special Administrative Region (SAR), China. The influenza transmission in Hong Kong SAR was predominated by influenza A(H3N2) virus. This increased transmission was also seen in the influenza associated hospital rates in this region; mainly the rates among 0-4 year old patients increased over the past month.
In the south of China, influenza activity remained at an interseasonal level. However, the number of influenza virus detections has been higher in this year?s interseasonal period compared to the previous year.
(...)
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 and RSV continued to be the most common respiratory virus detected in Argentina and Chile although cases had largely decreased.
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.
In Paraguay, the ILI consultation rate was higher than expected for the time of year, but with decreased influenza and respiratory virus detection.
In Uruguay the proportion of SARI-associated hospitalizations increased from levels reported in the previous week, but proportions of ICU admissions continued to decline.
(...)
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 was 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 seemed to have peaked.
In Australia, during the period from 30 August to 13 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. Influenza type B continued to represent over half of Victoria's influenza notifications. In recent weeks there have been increasing proportions of influenza B virus in Queensland and South Australia.
Influenza positivity levels ranged from 15% (309/2114) in the national sentinel laboratory surveillance to 28.1% (56/199) 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 had been relatively stable since mid-August. Almost 15% 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 was almost at the baseline threshold in early September, but decreased since then. Out of 303 samples received in the last week 161 were positive for influenza (53%): 49 were influenza B, 16 were influenza A(H3N2), 22 were influenza A(H1N1)pdm09 and 74 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
Contact fluupdate@who.int
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