INFLUENZA: World Health Organisation Global update, seasonal

Summary

Influenza activity varied in countries of temperate South America and increased steadily in the last few weeks in South Africa, but remained low overall in most of Oceania. Influenza activity in the temperate zone of the northern hemisphere was at inter-seasonal levels.

In temperate South America, influenza-like illness (ILI) activity and severe acute respiratory infection (SARI) indicators continued to increase in Chile and Paraguay. Influenza activity increased in Chile and remained elevated in Paraguay and Uruguay. Influenza A(H1N1)pdm09 virus circulated in Uruguay and co-circulated with influenza B viruses in Chile and Paraguay. In Argentina however, influenza activity (predominantly influenza A virus) seemed to decrease after a peak in the past few weeks, and ILI, SARI and pneumonia cases remained elevated but not increasing. Respiratory syncytial virus (RSV) activity remained elevated in the region.
In the temperate countries of Southern Africa, influenza detections continued to increase among ILI consultations with predominantly influenza B viruses detected, followed by A(H3N2) viruses.
In Oceania, influenza virus activity slightly increased but remained low. ILI activity in Australia and New Zealand remained low for this time of the year.
In the Caribbean countries, respiratory virus activity remained generally low. SARI cases and hospitalizations increased slightly in several countries and influenza B detections continued at low levels especially in Cuba.
In Central America, influenza activity continued in El Salvador with predominantly A(H1N1)pdm09 detected. In Panama, detections of influenza A(H1N1)pdm09 continued to decrease while detections of non-influenza respiratory viruses increased. RSV activity continued to increase in Costa Rica.
In tropical South America, respiratory virus activities generally decreased in recent weeks or remained low, with influenza A(H1N1)pdm09 predominant. In Colombia and the Plurinational State of Bolivia, influenza A(H1N1)pdm09 activity seemed to have peaked in the past few weeks at levels higher than peaks in the previous few years. ARI and SARI activities decreased but remained elevated compared to the same period last year in Colombia. Influenza A(H1N1)pdm09 detections continued to decrease in Ecuador. In Brazil and Peru, influenza A(H1N1)pdm09 activity remained low and SARI indicators continued to decrease in Brazil.
In tropical countries of South Asia, influenza activity was generally low with influenza A and B viruses co-circulating in the region.
In the northern temperate and central tropical regions of Africa, influenza activity was generally low with influenza A(H3N2) virus detections predominant in Western Africa and influenza B virus detections predominant in Eastern and Northern Africa, among the few countries reporting data during this period.
In North America and Europe, influenza activity was low with influenza B predominant. ILI levels were below seasonal thresholds.
Influenza activity was low in temperate Asia with influenza B virus predominant.
National Influenza Centres (NICs) and other national influenza laboratories from 65 countries, areas or territories reported data to FluNet for the time period from 27 June 2016 to 10 July 2016 (data as of 2016-07-22 04:17:11 UTC).The WHO GISRS laboratories tested more than 44063 specimens during that time period. 2366 were positive for influenza viruses, of which 1571 (66.4%) were typed as influenza A and 795 (33.6%) as influenza B. Of the sub-typed influenza A viruses, 601 (57.2%) were influenza A(H1N1)pdm09 and 450 (42.8%) were influenza A(H3N2). Of the characterized B viruses, 105 (34%) belonged to the B-Yamagata lineage and 204 (66%) to the B-Victoria lineage.