Influenza Sentinel Surveillance in Rwanda, 2008-2010
ABSTRACT Background. In 2008, Rwanda established an influenza sentinel surveillance (ISS) system to describe the epidemiology of influenza and monitor for the emergence of novel influenza A viruses. We report surveillance results from August 2008 to July 2010. Methods. We conducted ISS by monitoring patients with influenza-like illness (ILI) and severe acute respiratory infection (SARI) at 6 hospitals. For each case, demographic and clinical data, 1 nasopharyngeal specimen, and 1 oropharyngeal specimen were collected. Specimens were tested by real-time reverse-transcription polymerase chain reaction for influenza A and B viruses at the National Reference Laboratory in Rwanda. Results. A total of 1916 cases (945 ILI and 971 SARI) were identified. Of these, 29.2% (n = 276) of ILI and 10.4% (n = 101) of SARI cases tested positive for influenza. Of the total influenza-positive cases (n = 377), 71.8% (n = 271) were A(H1N1) pdm09, 5.6% (n = 21) influenza A(H1), 7.7% (n = 29) influenza A(H3), 1.6% (n = 6) influenza A (unsubtyped), and 13.3% (n = 50) influenza B. The percentage of positivity for influenza viruses was highest in October-November and February-March, during peaks in rainfall. Conclusions. The implementation of ISS enabled characterization of the epidemiology and seasonality of influenza in Rwanda for the first time. Future efforts should determine the population-based influenza burden to inform interventions such as targeted vaccination.
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ABSTRACT: OBJECTIVES: Influenza seasonality remains poorly studied in Equatorial regions. Here we assessed the seasonal characteristics and environmental drivers of influenza epidemics in French Guiana, where influenza surveillance was established in 2006. METHODS: Sentinel GPs monitored weekly incidence of Influenza-like illnesses (ILI) from January 2006 through December 2010 and collected nasopharyngeal specimens from patients for virological confirmation. Times series analysis was used to investigate relationship between ILI and climatic parameters (rainfall and specific humidity). RESULTS: Based on 1,533 viruses identified during the study period, we observed marked seasonality in the circulation of influenza virus in the pre-pandemic period, followed by year-round activity in the post-pandemic period, with a peak in the rainy season. ILI incidence showed seasonal autoregressive variation based on ARIMA analysis. Multivariate dynamic regression revealed that a 1mm increase of rainfall resulted in an increase of 0.33% in ILI incidence one week later, adjusting for specific humidity (SH). Conversely, an increase of 1g/kg of SH resulted in a decrease of 11% in ILI incidence 3 weeks later, adjusting for rainfall. CONCLUSIONS: Increased rainfall and low levels of specific humidity favor influenza transmission in French Guiana.The Journal of infection 04/2013; DOI:10.1016/j.jinf.2013.03.018 · 4.02 Impact Factor
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ABSTRACT: The epidemiology of influenza is largely based on data from developed countries.•Emerging data indicate that influenza is the etiology of 8% to 40% of influenza-like illness and 5% to 27% of severe acute respiratory illness in low-income countries.•The lack of access to health care and adequate healthcare infrastructure portends a disproportionate burden of influenza disease in resource-constrained environments.•Cardiopulmonary comorbidities are important risk factors for severe influenza.•Improved influenza surveillance is needed to guide resource allocation and basic healthcare infrastructure development.09/2014; 9(3). DOI:10.1016/j.gheart.2014.08.004