Mamadou Aliou Barry1, Florent Arinal2, Cheikh Talla2, Boris Gildas Hedible2, Fatoumata Diene Sarr2, Ibrahim Oumar Ba3, Boly Diop4, Ndongo Dia5, Muriel Vray2. 1. Institut Pasteur de Dakar, Unité d'Epidémiologie des maladies infectieuses, 36, Avenue Pasteur, Dakar, Sénégal. abarry@pasteur.sn. 2. Institut Pasteur de Dakar, Unité d'Epidémiologie des maladies infectieuses, 36, Avenue Pasteur, Dakar, Sénégal. 3. Organisation Mondiale de la Santé-Dakar, Dakar, Sénégal. 4. Ministère de la Santé et de l'Action Sociale, Direction de la Prévention, Dakar, Sénégal. 5. Institut Pasteur de Dakar, Pôle de Virologie, Dakar, Sénégal.
Abstract
BACKGROUND: Influenza is a major cause of morbidity and mortality in Africa. However, a lack of epidemiological data remains for this pathology, and the performances of the influenza-like illness (ILI) case definitions used for sentinel surveillance have never been evaluated in Senegal. This study aimed to i) assess the performance of three different ILI case definitions, adopted by the WHO, USA-CDC (CDC) and European-CDC (ECDC) and ii) identify clinical factors associated with a positive diagnosis for Influenza in order to develop an algorithm fitted for the Senegalese context. METHODS: All 657 patients with a febrile pathological episode (FPE) between January 2013 and December 2016 were followed in a cohort study in two rural villages in Senegal, accounting for 1653 FPE observations with nasopharyngeal sampling and influenza virus screening by rRT-PCR. For each FPE, general characteristics and clinical signs presented by patients were collected. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for the three ILI case definitions were assessed using PCR result as the reference test. Associations between clinical signs and influenza infection were analyzed using logistic regression with generalized estimating equations. Sore throat, arthralgia or myalgia were missing for children under 5 years. RESULTS: WHO, CDC and ECDC case definitions had similar sensitivity (81.0%; 95%CI: 77.0-85.0) and NPV (91.0%; 95%CI: 89.0-93.1) while the WHO and CDC ILI case definitions had the highest specificity (52.0%; 95%CI: 49.1-54.5) and PPV (32.0%; 95%CI: 30.0-35.0). These performances varied by age groups. In children < 5 years, the significant predictors of influenza virus infection were cough and nasal discharge. In patients from 5 years, cough, nasal discharge, sore throat and asthenia grade 3 best predicted influenza infection. The addition of "nasal discharge" as a symptom to the WHO case definition decreased sensitivity but increased specificity, particularly in the pediatric population. CONCLUSION: In summary, all three definitions studies (WHO, ECDC & CDC) have similar performance, even by age group. The revised WHO ILI definition could be chosen for surveillance purposes for its simplicity. Symptomatic predictors of influenza virus infection vary according the age group.
BACKGROUND:Influenza is a major cause of morbidity and mortality in Africa. However, a lack of epidemiological data remains for this pathology, and the performances of the influenza-like illness (ILI) case definitions used for sentinel surveillance have never been evaluated in Senegal. This study aimed to i) assess the performance of three different ILI case definitions, adopted by the WHO, USA-CDC (CDC) and European-CDC (ECDC) and ii) identify clinical factors associated with a positive diagnosis for Influenza in order to develop an algorithm fitted for the Senegalese context. METHODS: All 657 patients with a febrile pathological episode (FPE) between January 2013 and December 2016 were followed in a cohort study in two rural villages in Senegal, accounting for 1653 FPE observations with nasopharyngeal sampling and influenza virus screening by rRT-PCR. For each FPE, general characteristics and clinical signs presented by patients were collected. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for the three ILI case definitions were assessed using PCR result as the reference test. Associations between clinical signs and influenzainfection were analyzed using logistic regression with generalized estimating equations. Sore throat, arthralgia or myalgia were missing for children under 5 years. RESULTS: WHO, CDC and ECDC case definitions had similar sensitivity (81.0%; 95%CI: 77.0-85.0) and NPV (91.0%; 95%CI: 89.0-93.1) while the WHO and CDC ILI case definitions had the highest specificity (52.0%; 95%CI: 49.1-54.5) and PPV (32.0%; 95%CI: 30.0-35.0). These performances varied by age groups. In children < 5 years, the significant predictors of influenzavirus infection were cough and nasal discharge. In patients from 5 years, cough, nasal discharge, sore throat and asthenia grade 3 best predicted influenzainfection. The addition of "nasal discharge" as a symptom to the WHO case definition decreased sensitivity but increased specificity, particularly in the pediatric population. CONCLUSION: In summary, all three definitions studies (WHO, ECDC & CDC) have similar performance, even by age group. The revised WHO ILI definition could be chosen for surveillance purposes for its simplicity. Symptomatic predictors of influenzavirus infection vary according the age group.
Authors: E L Murray; S Khagayi; M Ope; G Bigogo; R Ochola; P Muthoka; K Njenga; F Odhiambo; D Burton; K F Laserson; R F Breiman; D R Feikin; M A Katz Journal: Epidemiol Infect Date: 2012-03-15 Impact factor: 4.434
Authors: Jean-Sebastien Casalegno; Daniel Eibach; Martine Valette; Vincent Enouf; Isabelle Daviaud; Sylvie Behillil; Astrid Vabret; Jean Claude Soulary; Mehdi Benchaib; Jean Marie Cohen; Sylvie van der Werf; Anne Mosnier; Bruno Lina Journal: Euro Surveill Date: 2017-04-06
Authors: D Thiam; M Niang; N Dia; F D Sarr; D Goudiab; M-L Senghor; D Kiori; T Faye; E Espié; I O Ba; V Richard Journal: Bull Soc Pathol Exot Date: 2014-09-26