Influenza Surveillance among Outpatients and Inpatients in Morocco, 1996–2009

Abstract

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.

Circulation of Respiratory Syncytial Virus in Morocco during 2014-2016: Findings from a sentinel-based virological surveillance system for influenza

“…Children below 5 years of age comprised of 35% of all patients enrolled in this study while the RSV detection rate in children under 5 years of age was 76%. This rate was high compared to the findings reported in USA and Turkey with 18% and 24.5% respectively (6)(7)(8)(9)(10)(11)(12)(13)(14)(15).Similar to our findings, Weber et al reported higher percentage of RSV-infection in children less than 6 months of age in developing countries (16). In this study, the higher percentage of RSV infection among infants may probably be due to nosocomial spread of the virus within paediatric care units during the high circulating season of RSV.…”

“…In temperate climate, RSV usually circulates during the winter season from November to April. Epidemics of RSV occurs when the circulation of influenza virus peak in the period from October through April (9). Although no clear seasonal pattern on the circulation of RSVs could be gathered from these data, the detection rate for RSV-positive infection was highest from November to March every year (during the fourth and the first quarter; P <0.001) while the detection rate was observed to have peaked in our study during week 52 of 2014 and week 3 of 2016.…”

Incidence of influenza virus-associated severe acute respiratory infection in Damanhour district, Egypt, 2013

“…This could be due to the fact that our incidence estimation is based on data from one year and from three hospitals only while in all these countries, data were collected over a period of three to one year while the data on influenzavirus positivity in all these countries are over a period of 3 to 5 years and since we know that the pre-dominant patterns of seasonal influenza virus keeps on changing, there is no surprise that while we found the influenza A (H3N2) virus to be predominantly circulating in 2013 in our study, in all these countries, the iinfluenza A/H1N1 was the predominant virus subtype co-circulating with influenza A/H3N2. However, what we noticed that the influenza seasonal pattern that we observed in Egypt mimic more closely with Tunisia and Morocco (22) In our study, we found out that the percentage of influenza-positivitty influenza positivity rate was detected amongst SARI cases, not all patients were sampled systematically and different sampling techniques were applied to collect either the nasopharyngeal or oropharyngeal swab.…”

Global Burden of Influenza as a Cause of Cardiopulmonary Morbidity and Mortality

“…In line with the WHO Global Agenda for Influenza Surveillance and Control, Morocco strengthened influenza sentinel surveillance in 2007. As a result 3102 respiratory samples were collected between 2007–2009 with 98 (3%) of these samples positive for influenza (20). The emergence of the 2009 H1N1 pandemic led to increased surveillance resulting in the collection of 3937 samples between June 2009 and February 2010 alone (15).…”