Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010-2012.

Background: Over the last decade, capacity for influenza surveillance and research in West Africa has strengthened. Data from these surveillance systems showed influenza A(H1N1)pdm09 circulated in West Africa later than in other regions of the continent.

Methods: We contacted 11 West African countries to collect information about their influenza surveillance systems (number of sites, type of surveillance, sampling strategy, populations sampled, case definitions used, number of specimens collected and number of specimens positive for influenza viruses) for the time period January 2010 through December 2012.

Influenza viruses in Nigeria, 2009-2010: results from the first 17 months of a national influenza sentinel surveillance system.

Background: Influenza surveillance data from tropical, sub-Saharan African countries are limited. To better understand the epidemiology of influenza, Nigeria initiated influenza surveillance in 2008.

Methods: Outpatients with influenza-like illness (ILI) and inpatients with severe acute respiratory illness (SARI) were enrolled at 4 sentinel facilities.