Evaluation of the influenza sentinel surveillance system in Madagascar, 2009­2014

Problem:Evaluation of influenza surveillance systems is poor, especially in Africa.ApproachIn 2007, the Institut Pasteur de Madagascar and the Malagasy Ministry of Public Health implemented a countrywide system for the prospective syndromic and virological surveillance of influenza-like illnesses. In assessing this system's performance, we identified gaps and ways to promote the best use of resources. We investigated acceptability, data quality, flexibility, representativeness, simplicity, stability, timeliness and usefulness and developed qualitative and/or quantitative indicators for each of these attributes.Local settingUntil 2007, the influenza surveillance system in Madagascar was only operational in Antananarivo and the observations made could not be extrapolated to the entire country.Relevant changes By 2014, the system covered 34 sentinel sites across the country. At 12 sites, nasopharyngeal and/or oropharyngeal samples were collected and tested for influenza virus. Between 2009 and 2014, 177718 fever cases were detected, 25 809 (14.5%) of these fever cases were classified as cases of influenza-like illness. Of the 9192 samples from patients with influenza-like illness that were tested for influenza viruses, 3573 (38.9%) tested positive. Data quality for all evaluated indicators was categorized as above 90% and the system also appeared to be strong in terms of its acceptability, simplicity and stability. However, sample collection needed improvement.Lessons learnt:The influenza surveillance system in Madagascar performed well and provided reliable and timely data for public health interventions. Given its flexibility and overall moderate cost, this system may become a useful platform for syndromic and laboratory-based surveillance in other low-resource settings

Pandemic Influenza A(H1N1) 2009 Virus Outbreak among Boarding School Pupils in Madagascar: Compliance and Adverse Effects of Prophylactic Oseltamivir Treatment

Introduction: In October 2009; the first outbreak of pandemic influenza A(H1N1) 2009 virus in Madagascar occurred at a school in Antananarivo. Among the first 12 cases; five were reported in boarding pupils at the school. The school closed 10 days into the outbreak. Mass oseltamivir prophylactic treatment was used to contain the outbreak. This study aimed to determine the transmission of infection among boarding school pupils and to evaluate the adverse effects of oseltamivir chemoprophylactic treatment and their impact on compliance.Methodology: After conducting an initial investigation of the outbreak we administered a questionnaire to 132 boarders who were present after the school re-opened. Questions addressed symptoms of influenza-like illness; compliance with chemoprophylaxis; and adverse effects. Results: Of 59 boarders; 20 (45.0) had confirmed pandemic influenza A (H1N1) infection. Among the asymptomatic boarders; compliance with oseltamivir chemoprophylaxis was moderate: 56.2took the full 10-day course; and 66.9completed at least seven days. In contrast; among symptomatic boarders; only two did not take the full course of oseltamivir. Fifty percent of the boarders receiving oseltamivir experienced symptoms such as fatigue (38.7); difficulty concentrating (22.6) and headaches (19.4). Bad compliance was not associated with adverse effects.Conclusion: Since the symptoms of pandemic influenza A(H1N1) 2009 virus were generally mild; the burden of adverse effects must be considered when deciding on mass oseltamivir chemoprophylaxis among teenagers