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Background Many countries in Africa have lacked sentinel surveillance systems for influenza and are under-represented in data used for global vaccine strain selection. Objectives We describe 8 years of sentinel surveillance data and the contribution of influenza and other viruses to medically attended influenza-like illness (ILI) in Côte d'Ivoire. Methods Sentinel surveillance was established in 2003. Nasopharyngeal (NP) specimens and epidemiologic data are collected from persons of all ages presenting with ILI at sentinel sites. Respiratory specimens have been tested for influenza using various viral and molecular diagnostic methods. A subset of 470 specimens collected from children aged 0-5 years were tested for multiple respiratory viruses using RT-PCR. Results From 2003 to 2010, 5074 NP specimens were collected from patients with ILI. Overall, 969/5074 (19%) of these specimens tested positive for influenza. Seasonal influenza A(H1N1) viruses predominated during 5 years and influenza A(H3N2) viruses predominated during 3 years. Influenza B viruses cocirculated with influenza A viruses during each year from 2004 to 2010. Seasonal peaks in influenza circulation were observed during the months of May, June, and October, with the largest peak corresponding with the primary rainfall season. Of 470 specimens collected from children under aged 5 who were tested for multiple respiratory viruses, a viral respiratory pathogen was detected in 401/470 (85%) of specimens. Commonly detected viruses were RSV (113 of 470 specimens, 24%), rhinoviruses (85/470, 18%), influenza (77/470, 16%), and parainfluenza (75/470, 16%). Conclusion In Côte d'Ivoire, there is a significant annual contribution of influenza and other respiratory viruses to medically attended ILI. [ABSTRACT FROM AUTHOR]

Background. Although recent work has described the spatiotemporal diffusion of influenza viruses worldwide, comprehensive data on spatiotemporal patterns of influenza from the African continent and Madagascar are still lacking.Methods. National Influenza Centers from 5 countries—Cameroon, Côte d'Ivoire, Madagascar, Niger, and Senegal—collected specimens from patients presenting with influenza-like illness who visited sentinel surveillance clinics during a 2-year period (2008–2009). Isolates were genetically and antigenically characterized.Results. Overall, 8312 specimens were tested. Seasonal influenza A virus subtypes H1N1 and H3N2 and influenza B viruses were detected in 329, 689, and 148 specimens, respectively. In 2009, pandemic influenza A virus subtype H1N1 was detected in Madagascar most commonly (98.5% of cases). Influenza activity was either significant year-round or occurred during a specific period of the year in the African countries we evaluated.Conclusions. Our results demonstrate that, from Madagascar to Senegal, the epidemiologic and virologic characteristics of influenza viruses are diverse in terms of spatiotemporal circulation of the different virus types, subtypes, and strains. Our data highlight the importance of country-specific surveillance and of data and virus sharing, and they provide a rational basis to aid policy makers to develop strategies, such as vaccination at the right moment and with the right formulation, aimed at reducing the disease burden in Africa and Madagascar. [ABSTRACT FROM AUTHOR]