TY - JOUR
T1 - Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010-2012
AU - Talla Nzussouo, Ndahwouh
AU - Duque, Jazmin
AU - Adedeji, Adebayo Abel
AU - Coulibaly, Daouda
AU - Sow, Samba
AU - Tarnagda, Zekiba
AU - Maman, Issaka
AU - Lagare, Adamou
AU - Makaya, Sonia
AU - Elkory, Mohamed Brahim
AU - Kadjo Adje, Herve
AU - Shilo, Paul Alhassan
AU - Tamboura, Boubou
AU - Cisse, Assana
AU - Badziklou, Kossi
AU - Maïnassara, Halima Boubacar
AU - Bara, Ahmed Ould
AU - Keita, Adama Mamby
AU - Williams, Thelma
AU - Moen, Ann
AU - Widdowson, Marc-Alain
AU - McMorrow, Meredith
N1 - FTX; DOAJ
PY - 2017
Y1 - 2017
N2 - 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.RESULTS: Of the 11 countries contacted, 8 responded: Burkina Faso, Cote d'Ivoire, Mali, Mauritania, Niger, Nigeria, Sierra Leone and Togo. Countries used standard World Health Organization (WHO) case definitions for influenza-like illness (ILI) and severe acute respiratory illness (SARI) or slight variations thereof. There were 70 surveillance sites: 26 SARI and 44 ILI. Seven countries conducted SARI surveillance and collected 3114 specimens of which 209 (7%) were positive for influenza viruses. Among influenza-positive SARI patients, 132 (63%) were influenza A [68 influenza A(H1N1)pdm09, 64 influenza A(H3N2)] and 77 (37%) were influenza B. All eight countries conducted ILI surveillance and collected 20,375 specimens, of which 2278 (11%) were positive for influenza viruses. Among influenza-positive ILI patients, 1431 (63%) were influenza A [820 influenza A(H1N1)pdm09, 611 influenza A(H3N2)] and 847 (37%) were influenza B. A majority of SARI and ILI case-patients who tested positive for influenza (72% SARI and 59% ILI) were children aged 0-4 years, as were a majority of those enrolled in surveillance. The seasonality of influenza and the predominant influenza type or subtype varied by country and year.CONCLUSIONS: Influenza A(H1N1)pdm09 continued to circulate in West Africa along with influenza A(H3N2) and influenza B during 2010-2012. Although ILI surveillance systems produced a robust number of samples during the study period, more could be done to strengthen surveillance among hospitalized SARI case-patients. Surveillance systems captured young children but lacked data on adults and the elderly. More data on risk groups for severe influenza in West Africa are needed to help shape influenza prevention and clinical management policies and guidelines.
AB - 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.RESULTS: Of the 11 countries contacted, 8 responded: Burkina Faso, Cote d'Ivoire, Mali, Mauritania, Niger, Nigeria, Sierra Leone and Togo. Countries used standard World Health Organization (WHO) case definitions for influenza-like illness (ILI) and severe acute respiratory illness (SARI) or slight variations thereof. There were 70 surveillance sites: 26 SARI and 44 ILI. Seven countries conducted SARI surveillance and collected 3114 specimens of which 209 (7%) were positive for influenza viruses. Among influenza-positive SARI patients, 132 (63%) were influenza A [68 influenza A(H1N1)pdm09, 64 influenza A(H3N2)] and 77 (37%) were influenza B. All eight countries conducted ILI surveillance and collected 20,375 specimens, of which 2278 (11%) were positive for influenza viruses. Among influenza-positive ILI patients, 1431 (63%) were influenza A [820 influenza A(H1N1)pdm09, 611 influenza A(H3N2)] and 847 (37%) were influenza B. A majority of SARI and ILI case-patients who tested positive for influenza (72% SARI and 59% ILI) were children aged 0-4 years, as were a majority of those enrolled in surveillance. The seasonality of influenza and the predominant influenza type or subtype varied by country and year.CONCLUSIONS: Influenza A(H1N1)pdm09 continued to circulate in West Africa along with influenza A(H3N2) and influenza B during 2010-2012. Although ILI surveillance systems produced a robust number of samples during the study period, more could be done to strengthen surveillance among hospitalized SARI case-patients. Surveillance systems captured young children but lacked data on adults and the elderly. More data on risk groups for severe influenza in West Africa are needed to help shape influenza prevention and clinical management policies and guidelines.
KW - Adolescent
KW - Adult
KW - Africa, Western/epidemiology
KW - Aged
KW - Child
KW - Child, Preschool
KW - Female
KW - Humans
KW - Infant
KW - Influenza A Virus, H1N1 Subtype/pathogenicity
KW - Influenza A Virus, H3N2 Subtype/pathogenicity
KW - Influenza, Human/epidemiology
KW - Male
KW - Middle Aged
KW - Seasons
KW - Severe Acute Respiratory Syndrome/epidemiology
KW - Young Adult
U2 - 10.1186/s12879-017-2839-1
DO - 10.1186/s12879-017-2839-1
M3 - A1: Web of Science-article
C2 - 29202715
SN - 1471-2334
VL - 17
JO - BMC Infectious Diseases
JF - BMC Infectious Diseases
IS - 1
M1 - 745
ER -