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. Epidemiologic data were obtained, and respiratory specimens were tested for influenza viruses, using real-time reverse-transcription polymerase chain reaction assays. RESULTS: During April 2009-August 2010, 2841 patients were enrolled. Of 2803 specimens tested, 217 (7.7%) were positive for influenza viruses (167 [8%] were from subjects with ILI, 17 [5%] were from subjects with SARI, and 33 were from subjects with an unclassified condition). During the prepandemic period, subtype H3N2 (A[H3N2]) was the dominant circulating influenza A virus subtype; 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) replaced A(H3N2) as the dominant circulating virus during November 2009. Among persons with ILI, A(H1N1)pdm09 was most frequently found in children aged 5-17 years, whereas among subjects with SARI, it was most frequently found in persons aged ≥ 65 years. The percentage of specimens that tested positive for influenza viruses peaked at 18.9% in February 2010, and the majority were A(H1N1)pdm09. CONCLUSIONS: Influenza viruses cause ILI and SARI in Nigeria. Data from additional years are needed to better understand the epidemiology and seasonality of influenza viruses in Nigeria.
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. Epidemiologic data were obtained, and respiratory specimens were tested for influenza viruses, using real-time reverse-transcription polymerase chain reaction assays. RESULTS: During April 2009-August 2010, 2841 patients were enrolled. Of 2803 specimens tested, 217 (7.7%) were positive for influenza viruses (167 [8%] were from subjects with ILI, 17 [5%] were from subjects with SARI, and 33 were from subjects with an unclassified condition). During the prepandemic period, subtype H3N2 (A[H3N2]) was the dominant circulating influenza A virus subtype; 2009 pandemic influenza A virus subtype H1N1 (A[H1N1]pdm09) replaced A(H3N2) as the dominant circulating virus during November 2009. Among persons with ILI, A(H1N1)pdm09 was most frequently found in children aged 5-17 years, whereas among subjects with SARI, it was most frequently found in persons aged ≥ 65 years. The percentage of specimens that tested positive for influenza viruses peaked at 18.9% in February 2010, and the majority were A(H1N1)pdm09. CONCLUSIONS:Influenza viruses cause ILI and SARI in Nigeria. Data from additional years are needed to better understand the epidemiology and seasonality of influenza viruses in Nigeria.
Authors: Martha I Nelson; Richard Njouom; Cecile Viboud; Mbayame N D Niang; Hervé Kadjo; William Ampofo; Adedeji Adebayo; Zekiba Tarnagda; Mark A Miller; Edward C Holmes; Ousmane M Diop Journal: J Infect Dis Date: 2014-01-19 Impact factor: 5.226
Authors: Issaka Maman; Kossi Badziklou; Essoya D Landoh; Afiwa W Halatoko; Talla N Nzussouo; Gabriel N Defang; Tsidi A Tamekloe; Pamela J Kennedy; Williams Thelma; Komlan Kossi; Zoulkarneiri Issa; Abiba B Kere Journal: BMC Public Health Date: 2014-09-20 Impact factor: 3.295
Authors: Justin R Ortiz; Kathleen M Neuzil; Colin R Cooke; Moni B Neradilek; Christopher H Goss; David K Shay Journal: PLoS One Date: 2014-11-25 Impact factor: 3.240