Giuseppe
Emeritus
[Source: World Health Organization, full PDF document: (LINK). Edited.]
Influenza Update N? 170, 12 October 2012
Summary
Countries in the temperate zone of the northern hemisphere
Influenza transmission in all reporting countries in the temperate regions of the northern hemisphere is still minimal, that is, at inter-seasonal levels.
In the United States of America, one additional laboratory-confirmed human case of influenza A(H3N2)v infection was reported since the last update, but no on-going human-to-human transmission has been identified. More information can be found at: http://www.cdc.gov/flu/swineflu/variant.htm
Throughout Europe, 23 countries reported data but influenza activity is still at inter-seasonal levels.
In the temperate Asian countries, with exception of Mongolia, overall ILI activity continued to remain low.
In Mongolia, ILI activity has increased over the last reporting weeks together with an increase of hospitalizations for pneumonia mainly due to a mixture of other non-influenza common respiratory viruses.
In northern China, during the week 10 to 16 September, the percentage of ILI visits in national sentinel hospitals was 2.8%, which was slightly but not significantly higher than that of the previous week. Of the specimens that were positive for influenza, 71% (12/17) tested positive for influenza A(H3N2) and 29% (5/17)for influenza B.
Countries in the tropical zone
Tropical countries of the Americas
Transmission in Central America, the Caribbean, and tropical South America continues to be at low levels in most reporting countries.
Across Central America, influenza B continues to be commonly detected.
Both Nicaragua and Costa Rica continue to report influenza B and A(H3N2) virus detections, whereas in Panama influenza activity continues to decline to almost undetectable levels.
In the tropical zone of South America, influenza activity is low.
In Brazil, the influenza activity continues to decrease to low levels. In 2012, influenza viruses were detected in 21% (3834/18105) of Severe Acute Respiratory Infection (SARI) cases. Of these, 67% (2570/3834) were due to influenza A(H1N1)pdm09. In 2012, 1559 SARI deaths were reported in Brazil, of which 409 (26%) were positive for an influenza virus.
Of these, 335 (82%) were positive for influenza A(H1N1)pdm09. Of the total deaths from SARI, 49% (769/1559) were female and the median age was 44 years (range 0-99 years); 61% were reported to have at least one comorbidity.
For distribution of respiratory viruses identified in sentinel ILI sites by age in Brazil, influenza A contributed to 40.7% of cases between 5 and 14 years, 50% of cases between 15 and 24 years, 42% of cases between 25 and 59 years, and 38% of cases 60 years or greater.
(...)
Sub-Saharan Africa
Of countries in Sub-Saharan Africa that have reported influenza data, Cameroon has reported an increase of mainly influenza A(H3N2) activity in the past weeks whereas in Ghana influenza activity seems to be decreasing with mainly influenza B virus detections. Kenya continues to report low level of influenza type B activity. Madagascar is reporting influenza B circulation at low levels.
Tropical Asia
A few areas of tropical Asia have experienced significant influenza virus circulation in the last weeks, especially in India, Nepal and Thailand, with a mixture of influenza B and Influenza A(H1N1)pdm09 virus circulation.
In southern China, influenza activity is very low, with 3.9% (46/1183) of samples tested being positive for influenza. Of the influenza positive samples 73% (34/46) were due to influenza A(H3N2), 20% (9/46 ) were influenza A not subtyped, 6% (3/46) were due to influenza B.
In Viet Nam, there is a decreasing trend of influenza activity where influenza B is the predominant virus reported. On the other hand, Lao PDR, has reported an increase in influenza activity with influenza A(H1N1)pdm09 being the main virus detected.
Cambodia continues to report activity at low levels with 79% (11/14) of influenza positive samples being positive for influenza A(H3N2) virus.
(...)
Countries in the temperate zone of the southern hemisphere
Influenza activity has continued to decline in all temperate countries of the southern hemisphere.
Temperate countries of South America
Influenza activity in the southern cone of South America continues to decrease in Chile, Paraguay and Argentina. After some late influenza activity, Argentina is now reporting a decline in influenza virus detections, with both influenza A(H1N1)pdm09 and influenza B virus detections.
ILI consultation rate in Chile remain low with 8.2 per 100 000 after a moderate season with highest ILI consultation rate of 19.4 per 100 000 at the beginning of July. In week 38 of all influenza positive samples, influenza B accounts for 65% (31/48); influenza A(H3N2) for 19% (9/48); influenza A non-subtyped for 17% (8/48). Since the beginning of 2012, the majority of SARI samples testing positive for influenza were due to influenza A (H3N2) virus. Of the 103 SARI deaths reported in 2012, 14 were confirmed with respiratory viruses. Of these, 64% (n=9) were influenza A(H3N2).
In Paraguay, influenza activity continues to remain at low levels with SARI hospitalization and ILI consultation rates reflecting this trend. In the current reporting week, of all tested respiratory viruses (n=5), 80% were influenza B. Of the SARI fatalities in 2012 with laboratory confirmed respiratory viruses (n=31), 18 (58%) were confirmed influenza A(H1N1)pdm09.
(...)
Temperate countries of southern Africa
In South Africa, influenza virus detections continue to decrease after a peak in late July with currently mainly influenza B virus transmission. ILI and SARI cases continue to decrease, with influenza B virus making up the majority of detections in SARI samples positive for influenza virus.
Oceania, Melanesia and Polynesia
The influenza season seems to come to an end in both Australia and New Zealand.
The majority of jurisdictions of Australia have reported influenza activity below baseline levels, and continue to report a decreasing trend. Nationally, influenza B was the most reported virus after a predominant influenza A(H3N2) season. In the period 15 ? 28 September 2012, of the 1470 influenza notifications reported, 53% (n=782) were influenza B and 46% (n=683) were influenza A, likely to be attributed to A(H3N2). So far in 2012, 57 influenza associated deaths have been reported to the National Notifiable Diseases Surveillance System (NNDSS), with a median age of 79 years. Almost all cases were reported as having influenza A (not subtyped) and are likely to be attributable to A(H3N2) virus infections.
In New Zealand, ILI consultation rates continue to decrease. A weekly ILI consultation rate of 12.7 per 100 000 was reported with influenza A(H3N2) being the main virus detected.
(...)
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? 170, 12 October 2012
Summary
- Seasonal influenza transmission has not been picked up yet in the northern temperate zone
- In the tropical areas most countries are reporting low or decreasing trends of influenza virus detections. The exceptions are Costa Rica in the Americas and India; Nepal, Lao PDR and Thailand in Asia.
- In Sub-Saharan Africa, Cameroon has reported an increase in influenza virus detections.
- The influenza season seem to come to an end in the temperate countries of the southern hemisphere.
Countries in the temperate zone of the northern hemisphere
Influenza transmission in all reporting countries in the temperate regions of the northern hemisphere is still minimal, that is, at inter-seasonal levels.
In the United States of America, one additional laboratory-confirmed human case of influenza A(H3N2)v infection was reported since the last update, but no on-going human-to-human transmission has been identified. More information can be found at: http://www.cdc.gov/flu/swineflu/variant.htm
Throughout Europe, 23 countries reported data but influenza activity is still at inter-seasonal levels.
In the temperate Asian countries, with exception of Mongolia, overall ILI activity continued to remain low.
In Mongolia, ILI activity has increased over the last reporting weeks together with an increase of hospitalizations for pneumonia mainly due to a mixture of other non-influenza common respiratory viruses.
In northern China, during the week 10 to 16 September, the percentage of ILI visits in national sentinel hospitals was 2.8%, which was slightly but not significantly higher than that of the previous week. Of the specimens that were positive for influenza, 71% (12/17) tested positive for influenza A(H3N2) and 29% (5/17)for influenza B.
Countries in the tropical zone
Tropical countries of the Americas
Transmission in Central America, the Caribbean, and tropical South America continues to be at low levels in most reporting countries.
Across Central America, influenza B continues to be commonly detected.
Both Nicaragua and Costa Rica continue to report influenza B and A(H3N2) virus detections, whereas in Panama influenza activity continues to decline to almost undetectable levels.
In the tropical zone of South America, influenza activity is low.
In Brazil, the influenza activity continues to decrease to low levels. In 2012, influenza viruses were detected in 21% (3834/18105) of Severe Acute Respiratory Infection (SARI) cases. Of these, 67% (2570/3834) were due to influenza A(H1N1)pdm09. In 2012, 1559 SARI deaths were reported in Brazil, of which 409 (26%) were positive for an influenza virus.
Of these, 335 (82%) were positive for influenza A(H1N1)pdm09. Of the total deaths from SARI, 49% (769/1559) were female and the median age was 44 years (range 0-99 years); 61% were reported to have at least one comorbidity.
For distribution of respiratory viruses identified in sentinel ILI sites by age in Brazil, influenza A contributed to 40.7% of cases between 5 and 14 years, 50% of cases between 15 and 24 years, 42% of cases between 25 and 59 years, and 38% of cases 60 years or greater.
(...)
Sub-Saharan Africa
Of countries in Sub-Saharan Africa that have reported influenza data, Cameroon has reported an increase of mainly influenza A(H3N2) activity in the past weeks whereas in Ghana influenza activity seems to be decreasing with mainly influenza B virus detections. Kenya continues to report low level of influenza type B activity. Madagascar is reporting influenza B circulation at low levels.
Tropical Asia
A few areas of tropical Asia have experienced significant influenza virus circulation in the last weeks, especially in India, Nepal and Thailand, with a mixture of influenza B and Influenza A(H1N1)pdm09 virus circulation.
In southern China, influenza activity is very low, with 3.9% (46/1183) of samples tested being positive for influenza. Of the influenza positive samples 73% (34/46) were due to influenza A(H3N2), 20% (9/46 ) were influenza A not subtyped, 6% (3/46) were due to influenza B.
In Viet Nam, there is a decreasing trend of influenza activity where influenza B is the predominant virus reported. On the other hand, Lao PDR, has reported an increase in influenza activity with influenza A(H1N1)pdm09 being the main virus detected.
Cambodia continues to report activity at low levels with 79% (11/14) of influenza positive samples being positive for influenza A(H3N2) virus.
(...)
Countries in the temperate zone of the southern hemisphere
Influenza activity has continued to decline in all temperate countries of the southern hemisphere.
Temperate countries of South America
Influenza activity in the southern cone of South America continues to decrease in Chile, Paraguay and Argentina. After some late influenza activity, Argentina is now reporting a decline in influenza virus detections, with both influenza A(H1N1)pdm09 and influenza B virus detections.
ILI consultation rate in Chile remain low with 8.2 per 100 000 after a moderate season with highest ILI consultation rate of 19.4 per 100 000 at the beginning of July. In week 38 of all influenza positive samples, influenza B accounts for 65% (31/48); influenza A(H3N2) for 19% (9/48); influenza A non-subtyped for 17% (8/48). Since the beginning of 2012, the majority of SARI samples testing positive for influenza were due to influenza A (H3N2) virus. Of the 103 SARI deaths reported in 2012, 14 were confirmed with respiratory viruses. Of these, 64% (n=9) were influenza A(H3N2).
In Paraguay, influenza activity continues to remain at low levels with SARI hospitalization and ILI consultation rates reflecting this trend. In the current reporting week, of all tested respiratory viruses (n=5), 80% were influenza B. Of the SARI fatalities in 2012 with laboratory confirmed respiratory viruses (n=31), 18 (58%) were confirmed influenza A(H1N1)pdm09.
(...)
Temperate countries of southern Africa
In South Africa, influenza virus detections continue to decrease after a peak in late July with currently mainly influenza B virus transmission. ILI and SARI cases continue to decrease, with influenza B virus making up the majority of detections in SARI samples positive for influenza virus.
Oceania, Melanesia and Polynesia
The influenza season seems to come to an end in both Australia and New Zealand.
The majority of jurisdictions of Australia have reported influenza activity below baseline levels, and continue to report a decreasing trend. Nationally, influenza B was the most reported virus after a predominant influenza A(H3N2) season. In the period 15 ? 28 September 2012, of the 1470 influenza notifications reported, 53% (n=782) were influenza B and 46% (n=683) were influenza A, likely to be attributed to A(H3N2). So far in 2012, 57 influenza associated deaths have been reported to the National Notifiable Diseases Surveillance System (NNDSS), with a median age of 79 years. Almost all cases were reported as having influenza A (not subtyped) and are likely to be attributable to A(H3N2) virus infections.
In New Zealand, ILI consultation rates continue to decrease. A weekly ILI consultation rate of 12.7 per 100 000 was reported with influenza A(H3N2) being the main virus detected.
(...)
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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