Thursday, 10 January 2013

WHO influenza update for China

Influenza activity remained at low levels throughout the temperate region of Asia, however, influenza-like illness (ILI) activity has increased for the 5th consecutive week in northern China.
The proportion of outpatient visits at sentinel surveillance sites that were due to ILI increased to 3.9 percent compared to 3.2 percent in the previous report. China has officially announced the start of the influenza season in northern China. 4 outbreaks were reported in the previous week, in Shanxi and Hubei Provinces, and there were no deaths attributed to acute respiratory infections. Influenza A accounted for 98 percent (188/192) of influenza viruses detected; 2 percent (4/192) were influenza B. Of the influenza A that were sub-typed, 81 percent were A(H3N2) and 19 percent were A(H1N1)pdm09. Among influenza viruses antigenically characterized by the Chinese National Influenza Center since October 2012, 198 (100 percent) influenza A(H3N2) viruses are related to A/Victoria/361/2011(H3N2)-like; 69 (95.8 percent) influenza B/Victoria viruses are related to B/Brisbane/60/2008-like; 6 (100 percent) influenza B/Yamagata viruses are related to B/Wisconsin/01/2010- like. None of the influenza samples tested were resistant to the neuraminidase inhibitors, oseltamivir and zanamivir.
Influenza activity in southern China, including Hong Kong SAR, remained below seasonal thresholds. In Singapore and southern China, half of the influenza virus positive samples were A(H3N2), and in Hong Kong SAR, 62 percent (28/45) were attributed to influenza A(H1N1)pdm09, and 4 percent influenza B. In southern China, influenza B detections increased.
Several unconfirmed media stories have reported a number of deaths related to infection with influenza A(H1N1)pdm09 in different parts of the world. As with other seasonal influenza viruses, it is expected that some deaths would occur with infection, in particular now, when influenza season starts in the northern hemisphere. These reports at times refer to this A(H1N1)pdm09 virus as "swine flu", causing some confusion with other viruses recently reported in the United States. A(H1N1)pdm09 virus has been circulating in humans for more than 3 years and now is a seasonal human influenza virus.
Source: ProMed Mail

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