Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses

Introduction: In Africa, the burden of influenza is largely unknown since surveillance schemes exist in very few countries. The National Institute of Hygiene in Morocco implemented a sentinel network for influenza surveillance in 1996. Methodology: Epidemiological and virological surveillances we...

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Main Authors: Amal Barakat, Abdelaziz Benjouad, Jean-Claude Manuguerra, Rajae El Aouad, Sylvie van der Werf
Format: Article
Language:English
Published: The Journal of Infection in Developing Countries 2010-09-01
Series:Journal of Infection in Developing Countries
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Online Access:https://jidc.org/index.php/journal/article/view/1065
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author Amal Barakat
Abdelaziz Benjouad
Jean-Claude Manuguerra
Rajae El Aouad
Sylvie van der Werf
author_facet Amal Barakat
Abdelaziz Benjouad
Jean-Claude Manuguerra
Rajae El Aouad
Sylvie van der Werf
author_sort Amal Barakat
collection DOAJ
description Introduction: In Africa, the burden of influenza is largely unknown since surveillance schemes exist in very few countries. The National Institute of Hygiene in Morocco implemented a sentinel network for influenza surveillance in 1996. Methodology: Epidemiological and virological surveillances were established and influenza viruses circulating in Morocco were characterised. Four practice-specific indicators were collected during the 1996-1997 season and nasopharyngeal swabs were collected from patients with an influenza-like illness during a three-year period (between 1996 and1998). Laboratory diagnosis was done by viral isolation. The isolates were characterized by hemagglutination- and neuraminidase-inhibition assays and by sequencing the hemagglutinin gene and phylogenetic analysis. Results: Among a total of 673 specimens, 107 (16%) were positive for influenza virus. Seasonal influenza strains were isolated from November to February. Antigenically, A(H1N1), A(H3N2) and B isolates were related to the vaccine strains. Genetically, one 1996/97 isolate A/Rabat/33/96 and the 1997/98 A(H3N2) isolates clustered with the new drift variant A/Sydney/5/97, a vaccine component of the 1998/99 season. Conclusions: These results indicate a seasonal circulation of influenza in Morocco concentrated between November and February. Further, the results demonstrate the importance of including the maximum number of countries in influenza surveillance to contribute to the definition of the influenza vaccine composition. 
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spelling doaj-art-34df78dceffd4cfb91a1555687b721252025-08-20T02:57:21ZengThe Journal of Infection in Developing CountriesJournal of Infection in Developing Countries1972-26802010-09-0150410.3855/jidc.1065Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza virusesAmal Barakat0Abdelaziz Benjouad1Jean-Claude Manuguerra2Rajae El Aouad3Sylvie van der Werf4Centre National de Référence de la grippe (Maroc), Institut National d'Hygiène, Rabat, MoroccoUniversity Mohammed V-Agdal, Rabat, MoroccoCellule d’Intervention Biologique d’Urgence, Institut Pasteur, Paris, FranceCentre National de Référence de la grippe (Maroc), Institut National d'Hygiène, Rabat, MoroccoUnité de Génétique Moléculaire des Virus Respiratoires, URA 1966 CNRS, Centre National de Référence de la Grippe (France-Nord), Institut Pasteur, Paris, France Introduction: In Africa, the burden of influenza is largely unknown since surveillance schemes exist in very few countries. The National Institute of Hygiene in Morocco implemented a sentinel network for influenza surveillance in 1996. Methodology: Epidemiological and virological surveillances were established and influenza viruses circulating in Morocco were characterised. Four practice-specific indicators were collected during the 1996-1997 season and nasopharyngeal swabs were collected from patients with an influenza-like illness during a three-year period (between 1996 and1998). Laboratory diagnosis was done by viral isolation. The isolates were characterized by hemagglutination- and neuraminidase-inhibition assays and by sequencing the hemagglutinin gene and phylogenetic analysis. Results: Among a total of 673 specimens, 107 (16%) were positive for influenza virus. Seasonal influenza strains were isolated from November to February. Antigenically, A(H1N1), A(H3N2) and B isolates were related to the vaccine strains. Genetically, one 1996/97 isolate A/Rabat/33/96 and the 1997/98 A(H3N2) isolates clustered with the new drift variant A/Sydney/5/97, a vaccine component of the 1998/99 season. Conclusions: These results indicate a seasonal circulation of influenza in Morocco concentrated between November and February. Further, the results demonstrate the importance of including the maximum number of countries in influenza surveillance to contribute to the definition of the influenza vaccine composition.  https://jidc.org/index.php/journal/article/view/1065Influenza AInfluenza BVirus isolationmolecular characterizationMorocco
spellingShingle Amal Barakat
Abdelaziz Benjouad
Jean-Claude Manuguerra
Rajae El Aouad
Sylvie van der Werf
Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
Journal of Infection in Developing Countries
Influenza A
Influenza B
Virus isolation
molecular characterization
Morocco
title Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
title_full Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
title_fullStr Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
title_full_unstemmed Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
title_short Virological surveillance in Africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
title_sort virological surveillance in africa can contribute to early detection of new genetic and antigenic lineages of influenza viruses
topic Influenza A
Influenza B
Virus isolation
molecular characterization
Morocco
url https://jidc.org/index.php/journal/article/view/1065
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