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

Investigation of an outbreak of acute respiratory disease in Côte d'Ivoire in april 2007

Background: This study aim was to investigate an outbreak of human cases of unexplained influenza-like illness and fatal acute respiratory infection (ARI); with simultaneous poultry illness and high mortality raising concerns of possible influenza A (H5N1); virus in Cote d'Ivoire in February and March 2007. Materials and Methods: To investigate the outbreak; we conducted active surveillance in the community and reviewed health registries. Persons meeting the case definition were asked to provide nasopharyngeal specimens. On the basis of clinical and epidemiological information; specimens were tested using conventional RT-PCR for the M gene of the influenza viruses and hemagglutinin H5 of avian influenza A (H5N1); virus; negative samples were tested for other respiratory viruses. Specimens from healthy animals were also collected. Results: Between October 2006; and February 2007; 104 suspected cases of Acute Respiratory Disease that included; 31 deaths recorded. We collected and tested 73 nasopharyngeal specimens; of which; 2; were positive for human Coronavirus OC43 and 1 for influenza C virus. No pathogens were identified in animal specimens. Conclusions: The investigation quickly ruled out influenza A (H5N1); virus as the cause and found laboratory-confirmed cases of influenza C virus and human Coronavirus OC 43 for the first time in both Cote d'Ivoire and in a Sub-Saharan African country. However we were not able to show that these viruses caused the outbreak. Monitoring of influenza viruses must be a priority but other respiratory viruses and non-viral causes may be of interest too