Giuseppe
Emeritus
[Source: World Health Organization, full PDF document: (LINK). Edited.]
Influenza Update N? 200, 9 December 2013
Summary
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 increased slightly over the past three weeks. In Mexico low levels influenza activity has been observed over the past two months.
Europe
Low levels of influenza activity in the WHO European Region continued, with only a few countries reporting sporadic influenza detections among samples from sentinel and non-sentinel sources (1% influenza positivity was reported in the EuroFlu weekly report (http://www.euroflu.org 2013/47). The number of hospitalizations due to severe acute respiratory infection (SARI) remained consistent at an interseasonal level. None of the SARI cases tested were found positive for influenza virus.
Northern Africa and the Western and Central Asia region
Influenza activity was low in the northern Africa and central Asia regions.
In Azerbaijan and Georgia, ILI activity increased since early September. Some influenza activity was reported in Bahrain, Israel, Jordan and Qatar.
Northern Asia
Influenza activity in the northern region of Asia increased since early October.
In Mongolia, clinical respiratory illness activity began to increase since mid-August, but ILI morbidity was still within the countrywide tolerance limits for this time of the year.
In the north of China, influenza detections increased from early October, with an influenza positivity rate of 1.3% reported last week, slightly higher than reported in previous weeks. Influenza A(H3N2), influenza A(H1N1pdm09), and influenza B were reported. Influenza B virus was the predominant virus detected.
(...)
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 were detected, indicating that influenza transmission had largely come to an end in the last few weeks in these countries.
Among positive samples, influenza B predominated in Cuba and the Domincan Republic, while influenza A predominated in Costa Rica, El Salvador, Guatemala, Jamaica and Nicaragua.
In Cuba, the number of SARI-associated hospitalizations increased, with two SARI-associated deaths reported.
In El Salvador, respiratory activity remained low and at similar levels to what has been observed in recent weeks.
In Nicaragua, RSV increased in recent weeks and has been the predomint circulating respiratory virus.
(...)
In tropical South America, respiratory virus activity remained low among most countries and continued to decrease following a period of high influenza activity in July and August.
In Venezuela, ARI and pneumonia levels decreased, but levels were within the expected values for the time of year.
In Ecuador the number of positive influenza samples slightly increased over the past three weeks, following two observed peaks this year, one ending in May of influenza A(H3N2) and one ending in early September of influenza A(H1N1)pdm09.
In Peru, reports of influenza reflected an end to the season which peaked in July of this year, and recent positive samples were predominantly influenza B, followed by RSV.
Brazil showed a continuing decline in the number of positive influenza samples since July, illustrating the end of the influenza season. Among positive samples reported over the past week, influenza A(unsubtyped) and adenovirus were detected.
Central African tropical region
Cote d?Ivoire and Ghana reported increased influenza virus detections.
In Cote d?Ivoire the number of influenza positive specimens were mostly influenza A(H3N2) and influenza A(H1N1)pdm, with some influenza B detected as well. In recent weeks Cote d?Ivoire has shown a transition from predominantly influenza B to mainly influenza A among positive samples.
Ghana reported primarily influenza A(H3N2) viruses in the past week, with a small number of influenza A(H1N1)pdm09 and influenza B positive samples as well.
Kenya reported influenza activity that has relatively decreased compared to the past four weeks, comprised of both influenza A and influenza B viruses.
(...)
Tropical Asia
Influenza transmission in southern Asia was low, with some sporadic influenza detections reported in India and Iran (Islamic Republic of).
Since early October a decrease in influenza detections as well as the influenza associated hospital rates and ILI consultation rates was seen in Hong Kong Special Administrative Region (SAR), China. Influenza positivity has been below 5% since November in this region.
In the south of China, influenza activity has increased over the past week and in the latest report an influenza positivity level of 9.3% was reported (compared to 7.6% in the last report). Influenza A(H3N2) virus was the main virus subtype reported, but influenza A(H1N1)pdm09 and influenza B viruses were also detected.
(...)
Overall, influenza transmission in South East Asia remained at a moderate level and was variable between countries.
In Lao People?s Democratic Republic, influenza activity had decreased in this reporting period, but some relatively high levels of influenza activity have been reported since early September, consisting of mainly influenza A(H1N1)pdm09 and A(H3N2) transmission.
ILI activity decreased in Thailand since early September, but seemed to be at a stable level below the baseline from early November, and RSV positivity also declined over the past three weeks. Since early November, influenza detections have increased, mainly due to increased influenza A(H3N2) transmission.
In Viet Nam, a decrease was seen in the number of influenza positive ILI samples and the number of positive influenza samples since early-October.
Cambodia reported an increase in influenza activity since mid-September, mainly due to increased influenza B 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 low levels which were expected for the time of year. Parainfluenza virus continued to circulate throughout the region, and influenza B virus was found to predomoniate in Paraguay.
In Chile the ILI activity remained low, and the number of reported influenza cases over the past three weeks indicated that influenza B virus predominated in influenza positive cases.
In Paraguay, the ILI consultation rate and number of influenza cases reported decreased compared to levels reported in the previous week. The influenza detection comprised mainly influenza B virus.
(...)
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 September and early October due to increased influenza A(H3N2), but data from the past three weeks showed that no influenza A virus and sporadic influenza B activity was detected.
(...)
Oceania, Melanesia and Polynesia
Overall, in Australia, New Zealand and the Pacific Islands influenza activity decreased. In Australia and New Zealand, all indicators showed a downward trend indicating the end of the season.
(...)
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? 200, 9 December 2013
Summary
- Overall influenza activity worldwide remained low.
- Influenza activity in North America remained low in general.
- Low levels of influenza activity in the WHO European Region continued with sporadic detections of influenza viruses reported from a few countries.
- In Asia, influenza activity slightly increased in Mongolia and the north of China. While in the south of China, slightly increased activity was observed. In Southeast Asia, influenza activity decreased in Lao People?s Democratic Republic, Thailand and Viet Nam. In this area, low levels of co-circulation of influenza A(H1N1)pdm09, 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. Respiratory syncytial virus (RSV) continued to predominate in certain countries, but within expected seasonal levels.
- Influenza activity in the southern hemisphere is largely over.
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 increased slightly over the past three weeks. In Mexico low levels influenza activity has been observed over the past two months.
Europe
Low levels of influenza activity in the WHO European Region continued, with only a few countries reporting sporadic influenza detections among samples from sentinel and non-sentinel sources (1% influenza positivity was reported in the EuroFlu weekly report (http://www.euroflu.org 2013/47). The number of hospitalizations due to severe acute respiratory infection (SARI) remained consistent at an interseasonal level. None of the SARI cases tested were found positive for influenza virus.
Northern Africa and the Western and Central Asia region
Influenza activity was low in the northern Africa and central Asia regions.
In Azerbaijan and Georgia, ILI activity increased since early September. Some influenza activity was reported in Bahrain, Israel, Jordan and Qatar.
Northern Asia
Influenza activity in the northern region of Asia increased since early October.
In Mongolia, clinical respiratory illness activity began to increase since mid-August, but ILI morbidity was still within the countrywide tolerance limits for this time of the year.
In the north of China, influenza detections increased from early October, with an influenza positivity rate of 1.3% reported last week, slightly higher than reported in previous weeks. Influenza A(H3N2), influenza A(H1N1pdm09), and influenza B were reported. Influenza B virus was the predominant virus detected.
(...)
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 were detected, indicating that influenza transmission had largely come to an end in the last few weeks in these countries.
Among positive samples, influenza B predominated in Cuba and the Domincan Republic, while influenza A predominated in Costa Rica, El Salvador, Guatemala, Jamaica and Nicaragua.
In Cuba, the number of SARI-associated hospitalizations increased, with two SARI-associated deaths reported.
In El Salvador, respiratory activity remained low and at similar levels to what has been observed in recent weeks.
In Nicaragua, RSV increased in recent weeks and has been the predomint circulating respiratory virus.
(...)
In tropical South America, respiratory virus activity remained low among most countries and continued to decrease following a period of high influenza activity in July and August.
In Venezuela, ARI and pneumonia levels decreased, but levels were within the expected values for the time of year.
In Ecuador the number of positive influenza samples slightly increased over the past three weeks, following two observed peaks this year, one ending in May of influenza A(H3N2) and one ending in early September of influenza A(H1N1)pdm09.
In Peru, reports of influenza reflected an end to the season which peaked in July of this year, and recent positive samples were predominantly influenza B, followed by RSV.
Brazil showed a continuing decline in the number of positive influenza samples since July, illustrating the end of the influenza season. Among positive samples reported over the past week, influenza A(unsubtyped) and adenovirus were detected.
Central African tropical region
Cote d?Ivoire and Ghana reported increased influenza virus detections.
In Cote d?Ivoire the number of influenza positive specimens were mostly influenza A(H3N2) and influenza A(H1N1)pdm, with some influenza B detected as well. In recent weeks Cote d?Ivoire has shown a transition from predominantly influenza B to mainly influenza A among positive samples.
Ghana reported primarily influenza A(H3N2) viruses in the past week, with a small number of influenza A(H1N1)pdm09 and influenza B positive samples as well.
Kenya reported influenza activity that has relatively decreased compared to the past four weeks, comprised of both influenza A and influenza B viruses.
(...)
Tropical Asia
Influenza transmission in southern Asia was low, with some sporadic influenza detections reported in India and Iran (Islamic Republic of).
Since early October a decrease in influenza detections as well as the influenza associated hospital rates and ILI consultation rates was seen in Hong Kong Special Administrative Region (SAR), China. Influenza positivity has been below 5% since November in this region.
In the south of China, influenza activity has increased over the past week and in the latest report an influenza positivity level of 9.3% was reported (compared to 7.6% in the last report). Influenza A(H3N2) virus was the main virus subtype reported, but influenza A(H1N1)pdm09 and influenza B viruses were also detected.
(...)
Overall, influenza transmission in South East Asia remained at a moderate level and was variable between countries.
In Lao People?s Democratic Republic, influenza activity had decreased in this reporting period, but some relatively high levels of influenza activity have been reported since early September, consisting of mainly influenza A(H1N1)pdm09 and A(H3N2) transmission.
ILI activity decreased in Thailand since early September, but seemed to be at a stable level below the baseline from early November, and RSV positivity also declined over the past three weeks. Since early November, influenza detections have increased, mainly due to increased influenza A(H3N2) transmission.
In Viet Nam, a decrease was seen in the number of influenza positive ILI samples and the number of positive influenza samples since early-October.
Cambodia reported an increase in influenza activity since mid-September, mainly due to increased influenza B 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 low levels which were expected for the time of year. Parainfluenza virus continued to circulate throughout the region, and influenza B virus was found to predomoniate in Paraguay.
In Chile the ILI activity remained low, and the number of reported influenza cases over the past three weeks indicated that influenza B virus predominated in influenza positive cases.
In Paraguay, the ILI consultation rate and number of influenza cases reported decreased compared to levels reported in the previous week. The influenza detection comprised mainly influenza B virus.
(...)
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 September and early October due to increased influenza A(H3N2), but data from the past three weeks showed that no influenza A virus and sporadic influenza B activity was detected.
(...)
Oceania, Melanesia and Polynesia
Overall, in Australia, New Zealand and the Pacific Islands influenza activity decreased. In Australia and New Zealand, all indicators showed a downward trend indicating the end of the season.
(...)
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
- Influenza reports from WHO Regional Offices:
- 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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