Influenza surveillance during the 2009-2010, 2010-2011, 2011-2012, and 2012-2013 seasons in Algeria.

We report the activity and circulation of influenza viruses in Algeria during four influenza seasons, from a national surveillance study carried out from 2009-2010 to 2012-2013. A total of 2766 samples from in- and outpatients, with no age restriction, were collected. The overall proportion of specimens that tested influenza positive was 46.