COMPARING INFLUENZA POSITIVITY RATES BY REAL-TIME RT-PCR, ELISA AND VIRAL CULTURE METHODS IN CÔTE 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 Côte 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’Ivoir

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 Côte 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

Influenza surveillance capacity improvements in Africa during 2011-2017.

BACKGROUND: Influenza surveillance helps time prevention and control interventions especially where complex seasonal patterns exist. We assessed influenza surveillance sustainability in Africa where influenza activity varies and external funds for surveillance have decreased. METHODS: We surveyed African Network for Influenza Surveillance and Epidemiology (ANISE) countries about 2011-2017 surveillance system characteristics. Data were summarized with descriptive statistics and analyzed with univariate and multivariable analyses to quantify sustained or expanded influenza surveillance capacity in Africa. RESULTS: Eighteen (75%) of 24 ANISE members participated in the survey; their cumulative population of 710 751 471 represent 56% of Africa's total population. All 18 countries scored a mean 95% on WHO laboratory quality assurance panels. The number of samples collected from severe acute respiratory infection case-patients remained consistent between 2011 and 2017 (13 823 vs 13 674 respectively) but decreased by 12% for influenza-like illness case-patients (16 210 vs 14 477). Nine (50%) gained capacity to lineage-type influenza B. The number of countries reporting each week to WHO FluNet increased from 15 (83%) in 2011 to 17 (94%) in 2017. CONCLUSIONS: Despite declines in external surveillance funding, ANISE countries gained additional laboratory testing capacity and continued influenza testing and reporting to WHO. These gains represent important achievements toward sustainable surveillance and epidemic/pandemic preparedness

Influenza surveillance in 15 countries in Africa, 2006-2010

BACKGROUND: In response to the potential threat of an influenza pandemic, several international institutions and governments, in partnership with African countries, invested in the development of epidemiologic and laboratory influenza surveillance capacity in Africa. METHODS: We used a standardized form to collect information on influenza surveillance system characteristics, the number and percent of influenza-positive patients with influenza-like illness (ILI) or severe acute respiratory infections (SARI) and virologic data. RESULTS: Between 2006 and 2010, the number of ILI and SARI sites in 15 African countries increased from 21 to 127 and from 2 to 98, respectively. Influenza was detected in 22% of ILI cases and 10% of SARI cases. Children 0-4 years accounted for 48% all ILI and SARI cases of which 20% and 10 respectively were positive for influenza. Influenza peaks were generally discernible in North and South Africa. Substantial co-circulation of influenza A and B occurred most years. CONCLUSIONS: Influenza is a major cause of respiratory illness in Africa, especially in children. Further strengthening influenza surveillance, along with conducting special studies on influenza burden, cost of illness, and role of other respiratory pathogens will help detect novel influenza viruses and inform and develop targeted influenza prevention policy decisions in the region.The work presented in this manuscript was funded completely or in part by host governments, Institute Pasteur, and cooperative agreements with the U.S. Centers for Disease Control and Prevention and/or the U.S. Department of Defense.http://www.journals.uchicago.edu/toc/jid/currenthb2013ay201

Additional file 8: Figure S6. of Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010–2012

Aggregate of influenza surveillance for influenza-like illness (ILI) and severe acute respiratory illness (SARI) data in Nigeria: 2010–2012. (DOCX 18 kb

Additional file 10: Figure S8. of Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010–2012

Aggregate of influenza surveillance for influenza-like illness (ILI) and severe acute respiratory illness (SARI) data in Togo: 2010–2012. (DOCX 40 kb

Additional file 9: Figure S7. of Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010–2012

Aggregate of influenza surveillance for influenza-like illness (ILI) and severe acute respiratory illness (SARI) data in Sierra Leone: 2010–2012. (DOCX 37 kb

Additional file 3: Figure S1. of Epidemiology of influenza in West Africa after the 2009 influenza A(H1N1) pandemic, 2010–2012

Aggregate of influenza surveillance for influenza-like illness (ILI) and severe acute respiratory illness (SARI) data in Burkina Faso: 2010–2012. (DOCX 39 kb