BackgroundThere is limited information about the epidemiology of influenza in Africa. We describe the epidemiology and seasonality of influenza in Morocco from 1996 to 2009 with particular emphasis on the 2007–2008 and 2008–2009 influenza seasons. Successes and challenges of the enhanced surveillance system introduced in 2007 are also discussed.MethodsVirologic sentinel surveillance for influenza virus was initiated in Morocco in 1996 using a network of private practitioners that collected oro-pharyngeal and naso-pharyngeal swabs from outpatients presenting with influenza-like-illness (ILI). The surveillance network expanded over the years to include inpatients presenting with severe acute respiratory illness (SARI) at hospitals and syndromic surveillance for ILI and acute respiratory infection (ARI). Respiratory samples and structured questionnaires were collected from eligible patients, and samples were tested by immunofluorescence assays and by viral isolation for influenza viruses.ResultsWe obtained a total of 6465 respiratory specimens during 1996 to 2009, of which, 3102 were collected during 2007–2009. Of those, 2249 (72%) were from patients with ILI, and 853 (27%) were from patients with SARI. Among the 3,102 patients, 98 (3%) had laboratory-confirmed influenza, of whom, 85 (87%) had ILI and 13 (13%) had SARI. Among ILI patients, the highest proportion of laboratory-confirmed influenza occurred in children less than 5 years of age (3/169; 2% during 2007–2008 and 23/271; 9% during 2008–2009) and patients 25–59 years of age (8/440; 2% during 2007–2009 and 21/483; 4% during 2008–2009). All SARI patients with influenza were less than 14 years of age. During all surveillance years, influenza virus circulation was seasonal with peak circulation during the winter months of October through April.ConclusionInfluenza results in both mild and severe respiratory infections in Morocco, and accounted for a large proportion of all hospitalizations for severe respiratory illness among children 5 years of age and younger.
Investment in SARS-CoV-2 sequencing in Africa over the past year has led to a major increase in the number of sequences generated, now exceeding 100,000 genomes, used to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence domestically, and highlight that local sequencing enables faster turnaround time and more regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and shed light on the distinct dispersal dynamics of Variants of Concern, particularly Alpha, Beta, Delta, and Omicron, on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve, while the continent faces many emerging and re-emerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century.
Widespread but delayed community transmission of A(H1N1)pdm09 occurred in Morocco in 2009, and A(H1N1)pdm09 became the dominant influenza virus subtype during the 2009-2010 influenza season. The transmissibility characteristics were similar to those observed in other countries.
Respiratory syncytial virus (RSV) is a leading cause of mortality and morbidity in young infants, little was known on its circulation types and patterns in Morocco. We conducted a prospective study using sentinel-based influenza surveillance to detect RSV by real time PCR in patients with acute respiratory infections, enrolled during two seasons (2014/15, 2015/16). During September 2014-April 2016, we obtained 1450 specimens, of which 267(18.4%) tested positive for RSV. The proportion of positive RSV infection was higher in patients hospitalized with acute respiratory infection compared to those with mild symptoms in out-patient clinics. The proportion of RSV infection was highest in children aged 0-6 months (45%; P < 0.001). Higher positivity rate was observed between months of December and March. RSV remains important viral etiological agent causing influenza-like illness and severe acute respiratory infections especially among infants in Morocco. Further surveillance, is required to understand better the risk factors of RSV infections. RÉSUMÉ Bien que le virus respiratoire syncytial (VRS) soit l'une des principales causes de mortalité et de morbidité chez les jeunes nourrissons, les modes et les tendances de la circulation de ce virus au Maroc sont très peu connus. Nous avons réalisé une étude prospective en recourant à la surveillance de la grippe basée sur des sites sentinelles dans le but de dépister le VRS grâce à la PCR en temps réel chez des patients souffrant d'infections respiratoires aiguës recrutés au cours de deux saisons (2014-2015 et 2015-2016). De septembre 2014 à avril 2016, nous avons prélevé 1450 échantillons, parmi lesquels 267 (18,4 %) se sont avérés positifs au VRS. La proportion d'infections positives au VRS était plus élevée chez les patients hospitalisés pour une infection respiratoire aiguë que chez les patients en consultation externe souffrant de légers symptômes. Cette proportion était la plus élevée chez les enfants de 0 à 6 mois (45 % ; p < 0,001). Le pic du taux de positivité a eu lieu de décembre à mars. Le VRS demeure un agent étiologique viral important au Maroc, responsable de syndromes de type grippal et d'infections respiratoires aiguës sévères, en particulier chez les nourrissons. Une surveillance renforcée est indispensable pour mieux comprendre les facteurs de risque des infections à VRS. ـروس فـ ـد املتوسط لرشق الصحية املجلة العرشون و الثاين املجلد السابع العدد 483
Background: Several statistical methods of variable complexity have been developed to establish thresholds for influenza activity that may be used to inform public health guidance. We compared the results of two methods and explored how they worked to characterize the 2018 influenza season performance-2018 season. Methods: Historical data from the 2005/2006 to 2016/2018 influenza season performance seasons were provided by a network of 412 primary health centers in charge of influenza like illness (ILI) sentinel surveillance. We used the WHO averages and the moving epidemic method (MEM) to evaluate the proportion of ILI visits among all outpatient consultations (ILI%) as a proxy for influenza activity. We also used the MEM method to evaluate three seasons of composite data (ILI% multiplied by percent of ILI with laboratory-confirmed influenza) as recommended by WHO. Results: The WHO method estimated the seasonal ILI% threshold at 0.9%. The annual epidemic period began on average at week 46 and lasted an average of 18 weeks. The MEM model estimated the epidemic threshold (corresponding to the WHO seasonal threshold) at 1.5% of ILI visits among all outpatient consultations. The annual epidemic period began on week 49 and lasted on average 14 weeks. Intensity thresholds were similar using both methods. When using the composite measure, the MEM method showed a clearer estimate of the beginning of the influenza epidemic, which was coincident with a sharp increase in confirmed ILI cases. Conclusions: We found that the threshold methodology presented in the WHO manual is simple to implement and easy to adopt for use by the Moroccan influenza surveillance system. The MEM method is more statistically sophisticated and may allow a better detection of the start of seasonal epidemics. Incorporation of virologic data into the composite parameter as recommended by WHO has the potential to increase the accuracy of seasonal threshold estimation.
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