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

Comparing influenza positivity rates by real-time rt-pcr, elisa and viral culture methods in Cote d'Ivoire, West Africa, in 2009

Detection of circulating influenza strains is a key public health concern especially in limited-resource settings where diagnosis capabilities remain a challenge. As part of multi-site surveillance in Cote d'Ivoire during the 2009 influenza A(H1N1) pandemic; we had the opportunity to test respiratory specimens collected from patients with acute respiratory illness (ARI). We analyzed and compared the percentage of specimens testing positive using three laboratory methods (rtRT-PCR; ELISA; viral culture). From January to October 2009; 1;356 respiratory specimens were collected from patients with acute respiratory illness and shipped at the WHO NIC (Institut Pasteur) Cote d'Ivoire; and 453 (33) tested positive for influenza by one or more laboratory methods. The proportion of positive influenza tests did not differ by the sex or age of the patient or presenting symptoms; but did differ depending on the timing and site of specimen collection. Of the 453 positive specimens; 424 (93.6) were detected by PCR; 199 (43.9) by ELISA and 40 (8.8) by viral culture. While seasonal influenza A(H1N1) virus strains were prominent; only four 2009 pandemic influenza A(H1N1) cases were detected. Use of molecular biology method (rtRT-PCR) increased sensitivity and diagnosis capabilities. Among all three methods used; rRT-PCR was the most sensitive and rapid method. More capacity building is still required for viral culture. Need to collect denominator data in order to have an accurate estimate of the burden of influenza. There was delayed introduction of pandemic influenza A(H1N1)2009 in Cote d'Ivoire