Giuseppe
Emeritus
[Source: World Health Organization, full PDF document: (LINK). Edited.]
Influenza Update N? 171, 26 October 2012
Summary
Countries in the temperate zone of the northern hemisphere
Many countries of the temperate regions of the northern hemisphere are beginning to report sporadic detections of influenza, however, none have yet experienced sustained community transmission or crossed seasonal thresholds for influenza-like illness.
In the United States of America, there have been no new reported cases of human influenza A(H3N2)v infection since the last update.
The last reported case had an onset of illness on 7 September 2012. More information can be found at: http://www.cdc.gov/flu/swineflu/variant.htm
Countries in the tropical zone
Tropical countries of the Americas
Influenza type B transmission has been active in some countries of Central America and the Caribbean in recent weeks but is generally declining.
El Salvador, Costa Rica, and Nicaragua have all reported recent transmission of influenza type B, with smaller numbers of A(H3N2).
Transmission in these countries appears to have peaked in late August and has been declining since then. The influenza B peak in Panama occurred a few weeks earlier than the other countries in the area while Honduras experienced a notable peak of influenza A(H1N1)pdm09 in April/May with no influenza B transmission.
In the Caribbean, Cuba and Jamaica have both reported persistent influenza B transmission in recent weeks since peaking much earlier in the year. Cuba has also reported small numbers of influenza A(H1N1)pdm09 virus in recent weeks.
In the tropical zone of South America, influenza activity continues to decline. Transmission peaked several weeks ago but has dropped off significantly and now only low numbers of virus detections are being reported. Influenza activity in the area was associated with all three circulating types and subtypes. Bolivia experienced a peak in May that was almost entirely influenza A(H1N1)pdm09, while in that same time frame Ecuador experienced a peak associated almost entirely with influenza type B and Columbia reported transmission of predominantly A(H3N2). Peru also reported transmission predominantly associated with influenza B more recently in June and July coinciding with the major peak of transmission in Brazil, which was evenly mixed with influenza A(H1N1)pdm09 and A(H3N2).
(...)
Sub-Saharan Africa
In West Africa, Senegal and Cote d?Ivoire have reported recent increases in influenza A(H3N2) detections in the past two-three weeks.
Further east in Central Africa, Cameroon has also experienced increasing transmission of A(H3N2) since late August. In eastern Africa, Kenya continues to report low levels of influenza B with even smaller numbers of influenza A(H3N2) detections.
Tropical Asia
A few areas of tropical Asia continue to experience influenza virus circulation, notably in Sri Lanka, Nepal and Thailand. Each of these three countries has reported a mixture of influenza B and Influenza A(H1N1)pdm09 circulation with the latter being slightly more common, particularly in more recent weeks.
In southern China, influenza activity continues to decrease. In the most recent week of reporting, the percentage of clinical samples from sentinel sites that tested positive for influenza virus was 2.4%, a continued decrease from previous weeks and well below the peak of nearly 50% in August. Likewise, influenza-like illness (ILI) only accounted for 2.2% of outpatient visits, below the level during the same period of the previous year. The Special Administrative Region of Hong Kong is also experiencing influenza activity at inter-seasonal baseline levels.
In Viet Nam, overall reports of ILI and severe acute respiratory infections (SARI) are decreasing. Out of 52 ILI samples tested, one was positive for influenza B and three for influenza A(H3N2) virus. Vietnam had a significant peak of transmission in June associated primarily with A(H3N2).
Lao PDR and Cambodia continue to report low numbers of influenza viruses. Activity appeared to peak in August in Lao, associated primarily with influenza A(H1N1)pdm09. In Cambodia, low numbers of A(H3N2) have been persistently detected for the previous five?six weeks. In the most recent week of reporting, 20% (10/50) of respiratory specimens tested were influenza positive; seven were A(H3N2), two were type B (lineage undetermined) and one was A(H1N1)pdm09.
(...)
Countries in the temperate zone of the southern hemisphere
Influenza activity has continued to decline in all temperate countries of the southern hemisphere and is now at inter-seasonal levels in most areas. A full summary report of the Southern Hemisphere influenza season will be published in the World Epidemiological Report November 2, 2012.
Temperate countries of South America
Influenza activity in the southern cone of South America continues to decrease in Chile, Paraguay and Argentina. Argentina continues to report a decline of both influenza A(H1N1)pdm09 and influenza B viruses with ILI and SARI cases reflecting this trend.
ILI consultation rate in Chile is 9.6 per 100 000, which is slightly higher than the previous week of 8.4 per 100 000, however SARI rates are decreasing. The maximum ILI consultation rate of 19.4 per 100 000 was seen at the beginning of July. In the current reporting period, influenza B accounts for the majority of all subtyped influenza viruses after a predominant influenza A(H3N2) season. Since the beginning of 2012, the majority of SARI samples testing positive for influenza were due to influenza A (H3N2) virus.
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=15), 47% were influenza B strains.
(...)
Temperate countries of southern Africa
In South Africa, influenza virus detections continue to decrease with mainly influenza B being reported.
(...)
Oceania, Melanesia and Polynesia
In Australia, influenza activity continues to decrease with the majority of jurisdictions reporting influenza activity below baseline levels.
Nationally, influenza B represented a large proportion of cases towards the end of the influenza season. Since the beginning of 2012, of all influenza positive samples, influenza A accounted for 78% (25 476/32 662); influenza B 22% (7186/32 662). Almost all cases were reported as having influenza A (not subtyped) and are likely to be attributable to A(H3N2) infections.
From 1 January to 15 October 2012, one influenza virus (out of 1314 tested) has shown resistance to the neuraminidase inhibitor oseltamivir.
(...)
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? 171, 26 October 2012
Summary
- Many countries of the Northern Hemisphere temperate region are reporting increasing sporadic detections of influenza viruses but numbers are still low and none have crossed their seasonal threshold.
- No recent cases of the swine origin influenza A(H3N2)v virus have been reported since the start of the school season in the United States of America.
- A few countries in tropical areas have experienced active transmission on influenza in recent weeks.
- Most notable are Nicaragua and Costa Rica in the Americas, where influenza type B has been the most commonly detected virus in recent weeks, and Sri Lanka, Nepal, and Thailand in Asia, where influenza A(H1N1)pdm09 has been slightly more common than influenza type B.
- In Sub-Saharan Africa, countries of West (Senegal and Cote d?Ivoire) and Central African (Cameroon) have reported increasing detections of influenza virus, primarily A(H3N2).
- Influenza activity in most areas of temperate countries of the Southern Hemisphere are now at inter-seasonal levels.
Countries in the temperate zone of the northern hemisphere
Many countries of the temperate regions of the northern hemisphere are beginning to report sporadic detections of influenza, however, none have yet experienced sustained community transmission or crossed seasonal thresholds for influenza-like illness.
In the United States of America, there have been no new reported cases of human influenza A(H3N2)v infection since the last update.
The last reported case had an onset of illness on 7 September 2012. More information can be found at: http://www.cdc.gov/flu/swineflu/variant.htm
Countries in the tropical zone
Tropical countries of the Americas
Influenza type B transmission has been active in some countries of Central America and the Caribbean in recent weeks but is generally declining.
El Salvador, Costa Rica, and Nicaragua have all reported recent transmission of influenza type B, with smaller numbers of A(H3N2).
Transmission in these countries appears to have peaked in late August and has been declining since then. The influenza B peak in Panama occurred a few weeks earlier than the other countries in the area while Honduras experienced a notable peak of influenza A(H1N1)pdm09 in April/May with no influenza B transmission.
In the Caribbean, Cuba and Jamaica have both reported persistent influenza B transmission in recent weeks since peaking much earlier in the year. Cuba has also reported small numbers of influenza A(H1N1)pdm09 virus in recent weeks.
In the tropical zone of South America, influenza activity continues to decline. Transmission peaked several weeks ago but has dropped off significantly and now only low numbers of virus detections are being reported. Influenza activity in the area was associated with all three circulating types and subtypes. Bolivia experienced a peak in May that was almost entirely influenza A(H1N1)pdm09, while in that same time frame Ecuador experienced a peak associated almost entirely with influenza type B and Columbia reported transmission of predominantly A(H3N2). Peru also reported transmission predominantly associated with influenza B more recently in June and July coinciding with the major peak of transmission in Brazil, which was evenly mixed with influenza A(H1N1)pdm09 and A(H3N2).
(...)
Sub-Saharan Africa
In West Africa, Senegal and Cote d?Ivoire have reported recent increases in influenza A(H3N2) detections in the past two-three weeks.
Further east in Central Africa, Cameroon has also experienced increasing transmission of A(H3N2) since late August. In eastern Africa, Kenya continues to report low levels of influenza B with even smaller numbers of influenza A(H3N2) detections.
Tropical Asia
A few areas of tropical Asia continue to experience influenza virus circulation, notably in Sri Lanka, Nepal and Thailand. Each of these three countries has reported a mixture of influenza B and Influenza A(H1N1)pdm09 circulation with the latter being slightly more common, particularly in more recent weeks.
In southern China, influenza activity continues to decrease. In the most recent week of reporting, the percentage of clinical samples from sentinel sites that tested positive for influenza virus was 2.4%, a continued decrease from previous weeks and well below the peak of nearly 50% in August. Likewise, influenza-like illness (ILI) only accounted for 2.2% of outpatient visits, below the level during the same period of the previous year. The Special Administrative Region of Hong Kong is also experiencing influenza activity at inter-seasonal baseline levels.
In Viet Nam, overall reports of ILI and severe acute respiratory infections (SARI) are decreasing. Out of 52 ILI samples tested, one was positive for influenza B and three for influenza A(H3N2) virus. Vietnam had a significant peak of transmission in June associated primarily with A(H3N2).
Lao PDR and Cambodia continue to report low numbers of influenza viruses. Activity appeared to peak in August in Lao, associated primarily with influenza A(H1N1)pdm09. In Cambodia, low numbers of A(H3N2) have been persistently detected for the previous five?six weeks. In the most recent week of reporting, 20% (10/50) of respiratory specimens tested were influenza positive; seven were A(H3N2), two were type B (lineage undetermined) and one was A(H1N1)pdm09.
(...)
Countries in the temperate zone of the southern hemisphere
Influenza activity has continued to decline in all temperate countries of the southern hemisphere and is now at inter-seasonal levels in most areas. A full summary report of the Southern Hemisphere influenza season will be published in the World Epidemiological Report November 2, 2012.
Temperate countries of South America
Influenza activity in the southern cone of South America continues to decrease in Chile, Paraguay and Argentina. Argentina continues to report a decline of both influenza A(H1N1)pdm09 and influenza B viruses with ILI and SARI cases reflecting this trend.
ILI consultation rate in Chile is 9.6 per 100 000, which is slightly higher than the previous week of 8.4 per 100 000, however SARI rates are decreasing. The maximum ILI consultation rate of 19.4 per 100 000 was seen at the beginning of July. In the current reporting period, influenza B accounts for the majority of all subtyped influenza viruses after a predominant influenza A(H3N2) season. Since the beginning of 2012, the majority of SARI samples testing positive for influenza were due to influenza A (H3N2) virus.
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=15), 47% were influenza B strains.
(...)
Temperate countries of southern Africa
In South Africa, influenza virus detections continue to decrease with mainly influenza B being reported.
(...)
Oceania, Melanesia and Polynesia
In Australia, influenza activity continues to decrease with the majority of jurisdictions reporting influenza activity below baseline levels.
Nationally, influenza B represented a large proportion of cases towards the end of the influenza season. Since the beginning of 2012, of all influenza positive samples, influenza A accounted for 78% (25 476/32 662); influenza B 22% (7186/32 662). Almost all cases were reported as having influenza A (not subtyped) and are likely to be attributable to A(H3N2) infections.
From 1 January to 15 October 2012, one influenza virus (out of 1314 tested) has shown resistance to the neuraminidase inhibitor oseltamivir.
(...)
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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