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 also increased in Chile and plateaued in Paraguay, while no influenza activity was reported in Uruguay. Influenza A(H1N1)pdm09 virus co-circulated with influenza B viruses in Chile and Paraguay. In Argentina however, influenza activity continued to decrease, and ILI and SARI 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 among ILI patients continued to rise, with a notable shift from influenza B to influenza A(H3N2) predominating. Among patients with pneumonia, the incidence of RSV detections continued to decline compared to recent reporting periods.
• In Oceania, influenza virus activity slightly increased but remained low. Influenza A(H3N2) predominated in Australia and New Caledonia where influenza activity increased in recent weeks, while New Zealand continued to see low levels of influenza activity. ILI activity in New Zealand remained low for this time of the year.
• In the Caribbean countries, influenza B detections continued at low levels. Other respiratory virus activity remained generally low. SARI cases and hospitalizations decreased slightly in several countries.
• In Central America, influenza and other respiratory virus activity remained low in El Salvador. In Panama, detections of influenza A(H1N1)pdm09 continued to decrease while detections of non-influenza respiratory viruses increased. In Costa Rica, influenza activity remained low while other respiratory virus activity increased with RSV predominating.
• In tropical South America, influenza A(H1N1)pdm09 and RSV activities generally decreased in recent weeks or remained low in most of the countries. SARI activities were continuing to decrease but remained elevated compared to the same period last year in Colombia. Influenza A(H1N1)pdm09 detections continued to decrease in Ecuador. In Peru, influenza activity continued to decline with co-circulation of A(H1N1)pdm09 and influenza B while detection of other respiratory viruses increased, with RSV predominating. In Ecuador, SARI-related RSV and influenza detections increased slightly but remained at low levels.
• 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 63 countries, areas or territories reported data to FluNet for the time period from 11 July 2016 to 24 July 2016 (data as of 2016-08-05 03:43:59 UTC). The WHO GISRS laboratories tested more than 33674 specimens during that time period. 1772 were positive for influenza viruses, of which 1149 (64.8%) were typed as influenza A and 594 (33.5%) as influenza B. Of the sub-typed influenza A viruses, 453 (50.3%) were influenza A(H1N1)pdm09 and 447 (49.7%) were influenza A(H3N2). Of the characterized B viruses, 75 (29.6%) belonged to the B-Yamagata lineage and 178 (70.4%) to the B-Victoria lineage.