Sentinel surveillance for influenza and other respiratory viruses in Côte d’Ivoire, 2003-2010

BackgroundThe importance of influenza viruses in respiratory infections in sub‐Saharan Africa has been historically overlooked, including in Burkina Faso.ObjectivesThis study therefore aimed at evaluating the prevalence and seasonal occurrence of influenza viruses in children under 5 years old, at risk of influenza‐related complications, presenting with influenza‐like illness (ILI) or severe acute respiratory infection (SARI). The study also aimed at identifying the periods with increased influenza transmission for vaccination recommendations in Burkina Faso.MethodsFrom January 2014 to December 2015, ILI and SARI (2015 only) patients were recruited in six healthcare centers in Burkina Faso. Influenza A and B molecular detection and subtyping were performed. Clade clustering of a subset of A(H1N1)pdm09 and A(H3N2) strains was deduced by performing phylogenetic analyses on hemagglutinin gene sequences. Weekly surveillance data from FluNet (2011‐2013; 2016) and this study (2014‐2015) were used to identify periods of increased influenza activity.ResultsInfluenza A and B viruses were detected in 15.1% (112 of 743) of ILI and 6.6% (12 of 181) of SARI patients. Overall, influenza A viruses were largely predominant (81 of 124, 65.3%), with 69.1% of A(H3N2) and 30.9% of A(H1N1)pdm09 strains. Four waves of increased transmission were identified in 2014‐2015, each dominated by different influenza subtypes and clades. Between 2011 and 2016, periods of increased influenza activity varied in their frequency, duration, and timing.ConclusionInfluenza A and B viruses were detected in a substantial number of ILI and SARI cases in Burkina Faso. Vaccination in September‐October would likely protect the highest number of patients.

Section: Discussionmentioning

confidence: 99%

Epidemiology and molecular characterization of influenza viruses in Burkina Faso, sub‐Saharan Africa

Sanou

Wandaogo

Poda

et al. 2018

“…Additionally, a review from sub‐Saharan African nations suggests influenza seasonality, aligning with the months of June–August and with timing generally corresponding to distance from the equator 22. Influenza prevalence exhibits seasonality coinciding with the rainy season in Cote d' Ivoire 23. Influenza diagnosed in children <11 years of age in Ghana exhibits slight seasonality during the months of May through July, again coinciding with the rainy season 24…”

Section: Discussionmentioning

confidence: 99%

Sentinel surveillance for influenza among severe acute respiratory infection and acute febrile illness inpatients at three hospitals in Ghana

Jones

Ampofo

Akuffo³

et al. 2016

BackgroundInfluenza epidemiology in Africa is generally not well understood. Using syndrome definitions to screen patients for laboratory confirmation of infection is an established means to effectively conduct influenza surveillance.MethodsTo compare influenza‐related epidemiologic data, from October 2010 through March 2013, we enrolled hospitalized severe acute respiratory infection (SARI; fever with respiratory symptoms) and acute febrile illness (AFI; fever without respiratory or other localizing symptoms) patients from three referral hospitals in Ghana. Demographic and epidemiologic data were obtained from enrolled patients after which nasopharyngeal and oropharyngeal swabs were collected, and processed by molecular methods for the presence of influenza viruses.ResultsOf 730 SARI patients, 59 (8%) were influenza positive; of 543 AFI patients, 34 (6%) were positive for influenza. Both SARI and AFI surveillance yielded influenza A(H3N2) (3% versus 1%), A(H1N1)pdm09 (2% versus 1%), and influenza B (3% versus 4%) in similar proportions. Data from both syndromes show year‐round influenza transmission but with increased caseloads associated with the rainy seasons.ConclusionsAs an appreciable percentage of influenza cases (37%) presented without defined respiratory symptoms, and thus met the AFI but not the SARI definition, it is important to consider broader screening criteria (i.e., AFI) to identify all laboratory‐confirmed influenza. The identified influenza transmission seasonality has important implications for the timing of related public health interventions.

“…One additional benefit of the surveillance was to raise clinician awareness about influenza. The implementation of national influenza centers in several West African countries for routine surveillance with the help of the World Health organization (WHO) and the Centers for Disease Control and Prevention (CDC) is a key step for better understanding and control of influenza disease in sub‐Saharan Africa …”

Section: Discussionmentioning

confidence: 99%

Sentinel surveillance of influenza in Burkina Faso: identification of circulating strains during 2010–2012

Tarnagda

Yougbaré

Ilboudo

et al. 2014

BackgroundAlthough influenza surveillance has recently been improved in some sub-Saharan African countries, no information is yet available from Burkina Faso.ObjectivesOur study was the first to determine the prevalence of influenza viruses circulating in Burkina Faso through a sentinel surveillance system.MethodsWe conducted sentinel surveillance with oropharyngeal (OP) swabs collected from outpatients (1 month to 83 years) from six sites in Bobo-Dioulasso and Ouagadougou, among patients meeting the WHO/CDC case definition for influenza-like illness (ILI; fever ≥38°C, and cough and/or sore throat in the absence of other diagnosis) from July 2010 to May 2012. Influenza viruses were detected by real-time RT-PCR using CDC primers, probes, and protocols.ResultsThe first three ILI cases were enrolled each day; of 881 outpatients with ILI enrolled and sampled, 58 (6·6%) tested positive for influenza viruses (29 influenza A and 29 influenza B). Among the influenza A viruses, 55·2% (16/29) were influenza A (H1N1)pdm09 and 44·8% (13/29) were seasonal A (H3N2). No cases of seasonal A/H1N1 were detected. Patients within 0–5 years and 6–14 years were the most affected, comprising 41·4% and 22·4% laboratory-confirmed influenza cases, respectively. Influenza infections occurred during both the dry, dusty Harmattan months from November to March and the rainy season from June to October with peaks in January and August.ConclusionsThis surveillance was the first confirming the circulation of influenza A (H1N1)pdm09, A/H3N2, and influenza B viruses in humans in Burkina Faso.